Name: surface properties of synthesized nanoporous carbon and silica matrices
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Description: Watch this Scientific Journal Video about Surface Properties of Synthesized Nanoporous Carbon and Silica Matrices at JoVE.com

The authors would like to thank the National Center of Science for providing financial support with grant no. DEC-2013/09/B/ST4/03711 and UMO-2016/22/ST4/00092. The authors are also grateful for the partial support from the Poland Operational Program Human Capital PO KL 4.1.1, as well as from the National Centre for Research and Development, under research grant no. PBS1/A9/13/2012. The authors are especially grateful for Prof. L. Ho&#322;ysz from Interfacial Phenomena Division, Faculty of Chemistry, Maria Curie-Sk&#322;odowska University, Lublin, Poland, for her kindness and enabling the measurements of the wettability in the SBA-15 nanopores.

1. Preparation of the OMC Materials
<ol>
	<li>Synthesis of a silica matrix as OMC precursor
	<ol>
		<li>Prepare 360 mL of 1.6 M HCl by adding 50 mL of HCl (36% - 38%) in a 500 mL round-bottom flask and, then, adding 310 mL of ultrapure water (resistivity of 18.2 M&#937;&#183;cm).</li>
		<li>To that, add 10 g of PE 10500 polymer (6.500 g/mol).</li>
		<li>Place the flask in an ultrasonic bath. Heat the solution to 35 &#176;C and stir it until the solid polymer is completely dissolved, making a homogeneou...

<ol>
	<li>Tao, Y., Kanoh, H., Abrams, L., Kaneko, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mesopore-Modified+Zeolites:+Preparation,+Characterization,+and+Applications.">Mesopore-Modified Zeolites: Preparation, Characterization, and Applications.</a> Chemical Reviews. , 896-910 (2006).</li><li>Wan, Y., Zhao, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+Controllable+Soft-Templating+Approach+to+Mesoporous+Silicates.">On the Controllable Soft-Templating Approach to Mesoporous Silicates.</a> Chemical Reviews. 107, 2821-2860 (2007).</li><li>Khder, A. E. S., Hassan, H. M. A., El-Shall, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acid+catalyzed+organic+transformations+by+heteropolytungstophosphoric+acid+supported+on+MCM-41.">Acid catalyzed organic transformations by heteropolytungstophosphoric acid supported on MCM-41.</a> Applied Catalysis A. 411, 77-86 (2012).</li><li>Zhao, D. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Triblock+Copolymer+Syntheses+of+Mesoporous+Silica+with+Periodic+50+to+300+Angstrom+Pores.">Triblock Copolymer Syntheses of Mesoporous Silica with Periodic 50 to 300 Angstrom Pores.</a> Science. 279, 548-552 (1998).</li><li>Linssen, T., Cassiers, K., Cool, P., Vansant, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mesoporous+templated+silicates:+an+overview+of+their+synthesis,+catalytic+activation+and+evaluation+of+the+stability.">Mesoporous templated silicates: an overview of their synthesis, catalytic activation and evaluation of the stability.</a> Advances in Colloid and Interface Science. 103, 121-147 (2003).</li><li>Eftekhari, A., Fan, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ordered+mesoporous+carbon+and+its+applications+for+electrochemical+energy+storage+and+conversion.">Ordered mesoporous carbon and its applications for electrochemical energy storage and conversion.</a> Materials Chemistry Frontiers. 1, 1001-1027 (2017).</li><li>Sing, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+porous+materials:+past,+present+and+future.">Characterization of porous materials: past, present and future.</a> Colloids and Surfaces A. 241, 3-7 (2004).</li><li>Huo, Q., Margolese, D. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generalized+synthesis+of+periodic+surfactant/inorganic+composite+materials.">Generalized synthesis of periodic surfactant/inorganic composite materials.</a> Nature. 368, 317-321 (1994).</li><li>Selvaraj, M., Kawi, S., Park, D. W., Ha, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+characterization+of+GaSBA-15:+Effect+of+synthesis+parameters+and+hydrothermal+stability.">Synthesis and characterization of GaSBA-15: Effect of synthesis parameters and hydrothermal stability.</a> Microporous and Mesoporous Materials. , 586-595 (2009).</li><li>Leonard, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toward+a+better+control+of+internal+structure+and+external+morphology+of+mesoporous+silicas+synthesized+using+a+nonionic+surfactant.">Toward a better control of internal structure and external morphology of mesoporous silicas synthesized using a nonionic surfactant.</a> Langmuir. 19, 5484-5490 (2003).</li><li>Liang, C., Li, Z., Dai, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mesoporous+Carbon+Materials:+Synthesis+and+Modification.">Mesoporous Carbon Materials: Synthesis and Modification.</a> Angewandte Chemie International Edition. 47, 3696-3717 (2008).</li><li>Babi&#263;, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+mesoporous+carbon+materials+synthesized+by+a+templating+procedure.">New mesoporous carbon materials synthesized by a templating procedure.</a> Ceramics International. 39 (4), 4035-4043 (2013).</li><li>Allen, S. J., Whitten, L., Mckay, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Production+and+Characterization+of+Activated+Carbons:+A+Review.">The Production and Characterization of Activated Carbons: A Review.</a> Developments in Chemical Engineering and Mineral Processing. 6, 231-261 (1998).</li><li>Kwak, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+Method+of+Co3O4+Nanoparticles+Using+Ordered+Mesoporous+Carbons+as+a+Template+and+Their+Application+for+Fischer-Tropsch+Synthesis.">Preparation Method of Co3O4 Nanoparticles Using Ordered Mesoporous Carbons as a Template and Their Application for Fischer-Tropsch Synthesis.</a> The Journal of Physical Chemistry C. 117 (4), 1773-1779 (2013).</li><li>Koo, H. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+the+ordered+meso-macroporous+structure+of+Co/SiO2+on+the+enhanced+activity+of+hydrogenation+of+CO+to+hydrocarbons.">Effect of the ordered meso-macroporous structure of Co/SiO2 on the enhanced activity of hydrogenation of CO to hydrocarbons.</a> Catalysis Science and Technology. 6, 4221-4231 (2016).</li><li>Jun, S., Joo, S. H., Ryoo, R., Kruk, M., Jaroniec, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+New,+Nanoporous+Carbon+with+Hexagonally+Ordered+Mesostructure.">Synthesis of New, Nanoporous Carbon with Hexagonally Ordered Mesostructure.</a> Journal of the American Chemical Society. 122 (43), 10712-10713 (2000).</li><li>Washburn, E. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+dynamics+of+capillary+flow.">The dynamics of capillary flow.</a> Physical Review Series2. 17, 273 (1921).</li><li>&#346;liwi&#324;ska-Bartkowiak, M., Sterczy&#324;ska, A., Long, Y., Gubbins, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+Microroughness+on+the+Wetting+Properties+of+Nano-Porous+Silica+Matrices.">Influence of Microroughness on the Wetting Properties of Nano-Porous Silica Matrices.</a> Molecular Physics. 112, 2365-2371 (2014).</li><li>&#346;liwi&#324;ska-Bartkowiak, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Melting/freezing+behavior+of+a+fluid+confined+in+porous+glasses+and+MCM-41:+dielectric+spectroscopy+and+molecular+simulation.">Melting/freezing behavior of a fluid confined in porous glasses and MCM-41: dielectric spectroscopy and molecular simulation.</a> Journal of Chemical Physics. 114, 950-962 (2001).</li><li>Coasne, B., Czwartos, J., &#346;liwi&#324;ska-Bartkowiak, M., Gubbins, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Freezing+of+mixtures+confined+in+silica+nanopores:+experiment+and+molecular+simulation.">Freezing of mixtures confined in silica nanopores: experiment and molecular simulation.</a> Journal of Chemical Physics. 133, 084701-084709 (2010).</li><li>Che&#322;kowski, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Dielectric Physics. , (1990).</li><li>Radhakrishnan, R., Gubbins, K. E., &#346;liwi&#324;ska-Bartkowiak, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Global+phase+diagrams+for+freezing+in+porous+media.">Global phase diagrams for freezing in porous media.</a> Journal of Chemical Physics. 116, 1147-1155 (2002).</li><li>Gubbins, K. E., Long, Y., &#346;liwi&#324;ska-Bartkowiak, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermodynamics+of+confined+nano-phases.">Thermodynamics of confined nano-phases.</a> Journal of Chemical Thermodynamics. 74, 169-183 (2014).</li><li>Radhakrishnan, R., Gubbins, K. E., &#346;liwi&#324;ska-Bartkowiak, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+the+fluid-wall+interaction+on+freezing+of+confined+fluids:+Toward+the+development+of+a+global+phase+diagram.">Effect of the fluid-wall interaction on freezing of confined fluids: Toward the development of a global phase diagram.</a> Journal of Chemical Physics. 112, 11048 (2000).</li><li>Cassie, A. B. D., Baxter, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wettability+of+porous+surfaces.">Wettability of porous surfaces.</a> Transactions of the Faraday Society. 40, 546 (1944).</li><li>Sing, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorption+methods+for+the+characterization+of+porous+materials.">Adsorption methods for the characterization of porous materials.</a> Advances in Colloid and Interface Science. 76, 3-11 (1998).</li><li>Sing, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+nitrogen+adsorption+for+the+characterisation+of+porous+materials.">The use of nitrogen adsorption for the characterisation of porous materials.</a> Colloids and Surfaces A. 187, 3-9 (2001).</li><li>Yu, C., Fan, J., Tian, B., Zhao, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphology+Development+of+Mesoporous+Materials:+a+Colloidal+Phase+Separation+Mechanism.">Morphology Development of Mesoporous Materials: a Colloidal Phase Separation Mechanism.</a> Chemistry of Materials. 16 (5), 889-898 (2004).</li><li>Liu, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhancement+of+Electrochemical+Hydrogen+Insertion+in+N-Doped+Highly+Ordered+Mesoporous+Carbon.">Enhancement of Electrochemical Hydrogen Insertion in N-Doped Highly Ordered Mesoporous Carbon.</a> The Journal of Physical Chemistry C. 118 (5), 2370-2374 (2014).</li><li>Choi, W. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Platinum+Nanoclusters+Studded+in+the+Microporous+Nanowalls+of+Ordered+Mesoporous+Carbon.">Platinum Nanoclusters Studded in the Microporous Nanowalls of Ordered Mesoporous Carbon.</a> Advanced Materials. 17, 446-451 (2005).</li><li>Rouquerol, F., Rouquerol, J., Sing, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Adsorption by Powders and Porous Solids: Principles, Methodology and Application. , (1999).</li><li>Gregg, S. J., Sing, K. S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Adsorption, Surface Area and Porosity. , (1982).</li><li>Llewellyn, P. L., Rouquerol, F., Rouquerol, J., Sing, K. S. W., Unger, K. K., Kreysa, G., Baselt, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Critical+appraisal+of+the+use+of+nitrogen+adsorption+for+the+characterization+of+porous+carbons.">Critical appraisal of the use of nitrogen adsorption for the characterization of porous carbons.</a> Characterization of Porous Solids V. , 421-427 (2000).</li><li>Sing, K. S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+gas+adsorption+for+the+characterization+of+porous+solids.">The use of gas adsorption for the characterization of porous solids.</a> Colloids and Surfaces. 38, 113-124 (1989).</li><li>Rouquerol, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recommendations+for+the+characterization+of+porous+solids.">Recommendations for the characterization of porous solids.</a> Pure &amp; Applied Chemistry. 66, 1739-1758 (1994).</li><li>Marega, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+direct+SAXS+approach+for+the+determination+of+specific+surface+area+of+clay+in+polymer-layered+silicate+nanocomposites.">A direct SAXS approach for the determination of specific surface area of clay in polymer-layered silicate nanocomposites.</a> The Journal of Physical Chemistry B. 116, 7596-7602 (2012).</li><li>Tsao, C. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neutron+Scattering+Methodology+for+Absolute+Measurement+of+Room-Temperature+Hydrogen+Storage+Capacity+and+Evidence+for+Spillover+Effect+in+a+Pt-Doped+Activated+Carbon.">Neutron Scattering Methodology for Absolute Measurement of Room-Temperature Hydrogen Storage Capacity and Evidence for Spillover Effect in a Pt-Doped Activated Carbon.</a> The Journal of Physical Chemistry Letters. 1, 1569-1573 (2010).</li><li>Mattson, J. S., Mark, H. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Activated Carbon: Surface Chemistry and Adsorption from Solution. , (1971).</li><li>L&#225;szl&#243;, K., Szucs, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+characterization+of+polyethyleneterephthalate+(PET)+based+activated+carbon+and+the+effect+of+pH+on+its+adsorption+capacity+from+aqueous+phenol+and+2,3,4-trichlorophenol+solutions.">Surface characterization of polyethyleneterephthalate (PET) based activated carbon and the effect of pH on its adsorption capacity from aqueous phenol and 2,3,4-trichlorophenol solutions.</a> Carbon. 39, 1945-1953 (2001).</li><li>Garten, V. A., Weiss, D. E., Willis, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+interpretation+of+the+acidic+and+basic+structures+in+carbons.">A new interpretation of the acidic and basic structures in carbons.</a> Australian Journal of Chemistry. 10, 309-328 (1957).</li><li>Boehm, H. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+oxides+on+carbon+and+their+analysis:+A+critical+assessment.">Surface oxides on carbon and their analysis: A critical assessment.</a> Carbon. 40, 145-149 (2002).</li><li>Menendez, J. A., Phillips, J., Xia, B., Radovic, L. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+modification+and+characterization+of+chemical+surface+properties+of+activated+carbon:+In+the+search+of+carbons+with+stable+basic+properties.">On the modification and characterization of chemical surface properties of activated carbon: In the search of carbons with stable basic properties.</a> Langmuir. 12, 4404-4410 (1996).</li></ol>

The critical steps during the preparation of the ordered mesoporous carbon material include the preparation of the ordered mesoporous silica materials as the template with well-defined structural properties that affect the properties of the final materials and a tempering/carbonization step under a nitrogen atmosphere. The modification of the typical method of preparation of the mesoporous ordered silicates with cylindrical pores28 concerns the application of an untypical structure-directing agent...

In 1992, ordered nanoporous silica materials were obtained for the first time, using an organic template; since then, a large number of publications related to different aspects of these structures, synthetic methods, the investigation of their properties, their modifications, and different applications have appeared in the literature1,2,3. The interest in SBA-15 nanoporous silica matrix4 is due to their unique quality: a high surface area, wide pores with a uniform pore size distribution, and good chemical and mechanical properties. Nanoporous silica materials with cylindrical pores, such as SBA-155, are often used as a porous matrix for catalysts as they are efficient catalysts in organic reactions6,7. The material can be synthesized with a wide range of methods that can influence their characteristics8,9,10. Therefore, it is crucial to optimize these methods for potential applications in many fields: electrochemical devices, nanotechnology, biology and medicine, drug delivery systems, or in adhesion and tribology. In the present study, two different types of nanoporous structures are presented, namely silica and carbon porous matrices. To compare their properties, the SBA-15 matrix is synthesized using the sol-gel method, and the ordered nanoporous carbon material is prepared by the impregnation of the resulting silica matrix with a carbon precursor.
Porous carbon materials are important in many appliances due to their high surface area and their unique and well-defined physicochemical properties6,11,12. Typical preparation results in materials with randomly distributed porosity and a disordered structure; there is also a limited possibility for the change of the general pore parameters, and thus, structures with relatively broad pore size distributions are obtained13. This possibility is broadened for nanoporous carbon materials with high surface areas and ordered systems of nanopores. More predicted geometry and more control of the physicochemical processes inside the pore space are important in many applications: as catalysts, separation media systems, advanced electronic materials, and nanoreactors in many scientific fields14,15.
To obtain the porous carbon replicas, the ordered silicates can act as a solid matrix to which carbon precursors are directly introduced. The method can be divided into several stages: the selection of ordered silica material; the deposition of a carbon precursor in a silica matrix; carbonization; then, the removal of the silica matrix. Many different types of carbonaceous materials can be obtained by this method, but not all nonporous materials have an ordered structure. An important element of the process is the selection of a suitable matrix whose nanopores must form a stable, three-dimensional structure16.
In this work, the influence of the type of pore walls on the surface properties of synthesized nanoporous matrices is investigated. The surface properties of OMC material are reflected by the surface properties of silica analog (SBA-15) of OMC. The textural and structural properties of both types of materials (OMC and SBA-15) are characterized by low-temperature N2 adsorption/desorption measurements (at 77 K), transmission electron microscopy (TEM), and energy dispersive X-ray analysis (EDX).
Low-temperature gas adsorption/desorption measurement is one of the most important techniques during the characterization of porous materials. Nitrogen gas is used as an adsorbate due to its high purity and the possibility to create a strong interaction with solid adsorbents. Important advantages of this technique are the user-friendly commercial equipment and relatively easy data-processing procedures. The determination of nitrogen adsorption/desorption isotherms is based on the accumulation of the adsorbate molecules on the surface of solid adsorbent at 77 K in a wide range of pressure (P/P0). The Barrett, Joyner, and Halenda (BJH) procedure for calculating the pore size distribution from experimental adsorption or desorption isotherms is applied. The most important assumptions of the BJH method include a planar surface and an even distribution of the adsorbate on the investigated surface. However, this theory is based on the Kelvin equation and it remains the most widely used manner for calculating the pore size distribution in the mesoporous range.
To evaluate the electrochemical character of the samples, a potentiometric titration method is applied. The surface chemistry of the material depends on the surface charge related to the presence of heteroatoms or functional groups on the surface. The surface properties are also investigated by contact angle analysis. The wettability inside the pores provides information about the adsorbate-adsorbent interactions. The influence of the wall roughness on the melting temperature of the water confined in both samples is studied with the dielectric relaxation spectroscopy (DRS) technique. Measurements of the dielectric constant allow the investigation of melting phenomena as the polarizability of the liquid and solid phases are different from each other. A change in the slope of the temperature dependence of the capacitance shows that melting occurs in the system.

<table>
	<tbody>
		<tr>
			<td>1,3,5-trimethylbenzene</td>
			<td>Sigma-Aldrich, Poland</td>
			<td>M7200 Sigma-Aldrich</td>
			<td>Mesitylene, also known as 1,3,5-trimethylbenzene, reagent grade, assay: 98%.</td>
		</tr>
		<tr>
			<td>anhydrous ethanol</td>
			<td>POCH, Avantor Performance Materials Poland S.A.</td>
			<td>396480111</td>
			<td>Assay, min. 99.8 %, analysis-pur (a.p.)</td>
		</tr>
		<tr>
			<td>ASAP 2020. Accelerated Surface Area and Porosimetry System</td>
			<td>Micromeritics Instrument Corporation, Norcross, GA, USA</td>
			<td></td>
			<td>Samples were outgassed before analysis at 120 oC for 24 hours in degas port of analyzer. The dead space volume was measured for calibration on experimental measurement using helium as a adsorbate.</td>
		</tr>
		<tr>
			<td>Automatic burette Dosimat 665</td>
			<td>Metrohm, Switzerland</td>
			<td></td>
			<td>The surface charge properties were experimentally determined by potentiometric titration of the suspension at constant temperature 20&#176;C maintained by the thermostatic device. Prior to potentiometric titration measurements, the solid samples were dried by 24 hours at 120 oC. The initial pH was established by addition of 0.3 cm3 of 0.2 mol/L HCl. T The 0.1 mol/L NaOH solution was used as a titrant, added gradually by using automatic burette.</td>
		</tr>
		<tr>
			<td>Digital pH-meter pHm-240</td>
			<td>Radiometer, Copenhagen</td>
			<td></td>
			<td>Device coupled with automatic burette</td>
		</tr>
		<tr>
			<td>ethyl alcohol</td>
			<td>POCH, Avantor Performance Materials Poland S.A.</td>
			<td>396420420</td>
			<td>Assay, min. 96 %.analysis-pur (a.p.)</td>
		</tr>
		<tr>
			<td>glucose</td>
			<td>POCH, Avantor Performance Materials Poland S.A.</td>
			<td>459560448</td>
			<td>assay 99.5%</td>
		</tr>
		<tr>
			<td>Hydrochloric acid</td>
			<td>POCH, Avantor Performance Materials Poland S.A.</td>
			<td>575283115</td>
			<td>Hydrochloric acid, 35 - 38% analysis-pur (a.p.)</td>
		</tr>
		<tr>
			<td>HOPG graphite substrate</td>
			<td>Spi Supplies</td>
			<td>LOT#1170906</td>
			<td>HOPG SPI-2 Grade, 20x20x1 mm</td>
		</tr>
		<tr>
			<td>Impedance analyzer Solartron 1260</td>
			<td>Solartron</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Pluronic PE 6400 polymer</td>
			<td>BASF (Polska)</td>
			<td></td>
			<td>(EO13PO70EO13)</td>
		</tr>
		<tr>
			<td>Pluronic PE10500</td>
			<td>BASF Canada Inc.</td>
			<td></td>
			<td>Molar mass 6500 g/mol</td>
		</tr>
		<tr>
			<td>potassium hydroxide</td>
			<td>Sigma-Aldrich, Poland</td>
			<td>P5958 Sigma-Aldrich</td>
			<td>BioXtra, &#8805;85% KOH basis</td>
		</tr>
		<tr>
			<td>SEM microscope</td>
			<td>JEOL JSM-7001F</td>
			<td></td>
			<td>Scanning Electron Microscope with EDS detector</td>
		</tr>
		<tr>
			<td>Sigma Force Tensiometer 701</td>
			<td>KSV, Sigma701, Biolin Scientific</td>
			<td></td>
			<td>force tensiometer</td>
		</tr>
		<tr>
			<td>Sulfuric acid (VI)</td>
			<td>POCH, Avantor Performance Materials Poland S.A.</td>
			<td>575000115</td>
			<td></td>
		</tr>
		<tr>
			<td>surface glass type KS 324 Kavalier</td>
			<td>Megan Poland</td>
			<td></td>
			<td>80 % of SiO2 , 11% of Na2O and 9% of CaO</td>
		</tr>
		<tr>
			<td>Tecnai G2 T20 X-TWIN</td>
			<td>FEI, USA</td>
			<td></td>
			<td>Transmission Electron Microscope with EDX detector.</td>
		</tr>
		<tr>
			<td>TEM microscope</td>
			<td>JEOL JEM-1400</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>temperature controller ITC503</td>
			<td>Oxford Instruments</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tetraethylorthosilicate</td>
			<td>Sigma-Aldrich, Poland</td>
			<td>131903</td>
			<td>Tetraethyl silicate, TEOS, reagent grade, assay 98%</td>
		</tr>
		<tr>
			<td>Ultrapure water</td>
			<td>Millipore, Merck KGaA, Darmstadt, Germany</td>
			<td>SIMSV0001</td>
			<td>Simplicity Water Purification SystemUltrapure Water: 18.2 MegOhm&#183;cm, TOC: &#60;5 ppb</td>
		</tr>
	</tbody>
</table>

surface properties of synthesized nanoporous carbon and silica matrices

In this work, we report the synthesis and characterization of ordered nanoporous carbon material (also called ordered mesoporous carbon material [OMC]) with a 4.6 nm pore size, and ordered silica porous matrix, SBA-15, with a 5.3 nm pore size. This work describes the surface properties of nanoporous molecular sieves, their wettability, and the melting behavior of D2O confined in the differently ordered porous materials with similar pore sizes. For this purpose, OMC and SBA-15 with highly ordered nanoporous structures are synthesized via impregnation of the silica matrix by applying a carbon precursor and by the sol-gel method, respectively. The porous structure of investigated systems is characterized by an N2 adsorption-desorption analysis at 77 K. To determine the electrochemical character of the surface of synthesized materials, potentiometric titration measurements are conducted; the obtained results for OMC shows a significant pHpzc shift toward the higher values of pH, relative to SBA-15. This suggests that investigated OMC has surface properties related to oxygen-based functional groups. To describe the surface properties of the materials, the contact angles of liquids penetrating the studied porous beds are also determined. The capillary rise method has confirmed the increased wettability of the silica walls relative to the carbon walls and an influence of the pore roughness on the fluid/wall interactions, which is much more pronounced for silica than for carbon mesopores. We have also studied the melting behavior of D2O confined in OMC and SBA-15 by applying the dielectric method. The results show that the depression of the melting temperature of D2O in the pores of OMC is about 15 K higher relative to the depression of the melting temperature in SBA-15 pores with a comparable 5 nm size. This is caused by the influence of adsorbate/adsorbent interactions of the studied matrices.

To characterize the porous structure of the investigated samples of OMC and SBA-15, the N2 adsorption-desorption isotherms were recorded at 77 K. The experimental N2 gas adsorption-desorption isotherms characterizing the investigated systems, as well as the pore size distributions (PSD) obtained from the adsorption and desorption data, are presented in Figure 1A-D. The position of the inflection points on the sorption is...

Watch this Scientific Journal Video about Surface Properties of Synthesized Nanoporous Carbon and Silica Matrices at JoVE.com

Surface Properties of Synthesized Nanoporous Carbon and Silica Matrices

Here we report the synthesis and characterization of ordered nanoporous carbon (with a 4.6 nm pore size) and SBA-15 (with a 5.3 nm pore size). The work describes the surface and textural properties of nanoporous molecular sieves, their wettability, and the melting behavior of D2O confined in the materials.

In this work, we report the synthesis and characterization of ordered nanoporous carbon material (also called ordered mesoporous carbon material [OMC]) ...

This protocol is significant because porous surface characteristic relating to the confinement effect of liquids in porous matrices is a key problem in energy, medicine, and environment application. A synthesis and characterization of the new materials, carbon and silica nanopores, and determination of the wetting parameters provide new information about properties of the confinement nanophases. In nanotechnology, biology, and medicine, it is crucial to optimize the synthesis methods for new materials in order to obtain a product with desired properties.Essential synthesis and their characterization methods should be apparent and present in order to obtain product with desired structural and surface properties. The visual demonstration of this procedure is important as it provides a detailed explanation of the applied procedures and ensures a repeatable performance. Demonstrating of the procedure will be Dr.Malgorzata Zienkiewicz-Strzalka, a postdoc from the Faculty of Chemistry of Maria Curie-Sklodowska University, and Dr.Angelina Sterczynska, a postdoc from my laboratory.To begin, prepare 360 milliliters of 1.6-molar hydrochloric acid in a 500-milliliter round-bottom flask. To the flask, add 10 grams of polyethylene 10500 polymer. Then place the flask in an ultrasonic bath and heat the solution to 35 degrees Celsius.Stir it until the solid polymer is completely dissolved, making a homogenous mixture. Next add 10 grams of 1, 3, 5-trimethylbenzene to the flask and stir the content while maintaining it at 35 degrees Celsius in the water bath. After stirring for 30 minutes, add 34 grams of tetraethyl orthosilicate to the flask.Over 10 minutes, add the tetraethyl orthosilicate slowly and dropwise with constant stirring. Then stir the mixture for an additional 20 hours at 35 degrees Celsius. After 20 hours, transfer the contents of the flask into a PTFE cartridge.Place the cartridge in an autoclave, and bake the solution for 24 hours at 90 degrees Celsius. The next day, use a Buchner funnel to filter the resulting precipitate. Then wash it with distilled water, using at least one liter of water.Dry the obtained solid at room temperature, and use a muffle furnace in an air atmosphere to apply a thermal treatment to the sample at 500 degrees Celsius for six hours. Start by preparing two impregnation solutions with appropriate proportions of water, three-molar sulfuric acid, and glucose, where glucose plays the role of carbon precursor, and sulfuric acid acts as catalyst. To prepare impregnation solution one, mix five grams of water, 0.14 grams of three-molar sulfuric acid, and 1.25 grams of glucose for each gram of silica.Then prepare impregnation solution two. For this solution, mix five grams of water, 0.8 grams of three-molar sulfuric acid, and 0.75 grams of glucose for each gram of silica. Place one gram of the silica material, one gram of impregnation solution one, and the catalyst in a 500-milliliter flask.Heat the mixture in a vacuum dryer at 100 degrees Celsius for six hours. Next add one gram of impregnation solution two to the mixture in the vacuum dryer, and heat the mixture again in the vacuum dryer at 160 degrees Celsius for 12 hours. Transfer the obtained composite to a mortar, and grind the particles to create a homogenous mixture.Place the obtained product into the flow furnace under nitrogen, and heat it to 700 degrees Celsius at a heating rate of 2.5 degrees Celsius per minute. Hold the material at this temperature for six hours under a nitrogen atmosphere. After six hours, turn off the furnace, and allow the solution to cool before opening the furnace.First prepare 100 milliliters of etching solution. Mix 50 milliliters of 95%ethyl alcohol and 50 milliliters of water. To this, add seven grams of potassium hydroxide, and stir until it is dissolved.Place all of the obtained carbonized material in a 250-milliliter round-bottom flask, and add 100 milliliters of etching solution. Supply the system with a reflux condenser and a magnetic stirrer. Heat the mixture to a boil while stirring constantly, and allow it to boil for one hour.Transfer the obtained material to the Buchner funnel. Wash it with at least four liters of distilled water, and then dry it. If desired, characterize the material using low-temperature nitrogen absorption-desorption measurements, TEM imaging, energy-dispersive X-ray spectroscopy, potentiometric titration measurements, and/or dielectric relaxation spectroscopy as described in the accompanying text protocol.Nitrogen sorption and TEM methods have shown highly ordered mesoporous structures of synthesized materials. The EDS and potentiometric titration methods have shown the OMC is characterized by decreasing the acid sites and reduction of oxygen content. To determine the contact angle inside the pores of the studied samples, start by applying the modified Washburn's equation, shown here and described in the text protocol, to estimate the values of the advancing contact angles inside the studied pores.Then prepare the force tensiometer. For powders, prepare a small tube with a diameter of three millimeters. For a liquid, prepare a vessel with a diameter of 22 millimeters and a maximum volume of 10 milliliters.Next start the computer program connected to the tensiometer. Then put a vessel with a liquid on a motor-driven stage, and suspend the glass tube with the sample on an electric balance. Start the motor and approach the sample at a constant rate of 10 millimeters per minute.Set the immersion depth of the sample tube into the liquid so that it is equal to one millimeter. Stop the experiment when m squared equals f of t starts to show the characteristic plateau. The wettability inside the pores is strongly dependent on the roughness of the pore, the kind of the wall, and the porosity.The wettability of liquids in pores is significantly different than that on ideal, flat surface. Here are sample results of the measurements of contact angles inside the nanopores of ordered mesoporous carbon material. Also shown is the referenced wettability of smooth, highly-oriented pyrolytic graphite.The measured contact angles are shown as a function of the microscopic wetting parameter. The lower the contact angle, the higher the wettability, which means that the interaction of the penetrating liquid molecule with the studied surface is stronger. The measured contact angles have indicated better wettability of the silica walls than the OMC walls and suggests that an influence of pore roughness on the fluid-wall interactions is more pronounced for silica than for carbon nanopores.In addition to what was shown here, the adsorbent-adsorbate interaction, by means of a dielectric on Fourier-transform infrared spectroscopy or structural analysis by X-ray, can give additional insight into the molecular dynamics of materials. The techniques used for characterization of surface properties of nanomaterials may also be applied to the interactions between the material's surface and biological active substances. Please be caution when impregnating the silica matrix, as this step is hazardous due to the toxic sulfuric acid.

surface-properties-synthesized-nanoporous-carbon-silica

Research

JoVE Journal

Chemistry

Preparation of Silica Nanoparticles Through Microwave-assisted Acid-catalysis

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle diameters ranging from 30-250 nm by varying the reaction conditions. Through the selection of a microwave compatible solvent, silicic acid precursor, catalyst, and microwave irradiation time, these microwave-assisted methods were capable of overcoming the previously reported shortcomings associated with synthesis of silica nanoparticles using microwave reactors. The siloxane precursor was hydrolyzed using the acid catalyst, HCl. Acetone, a low-tan &#948; solvent, mediates the condensation reactions and has minimal interaction with the electromagnetic field. Condensation reactions begin when the silicic acid precursor couples with the microwave radiation, leading to silica nanoparticle sol formation. The silica nanoparticles were characterized by dynamic light scattering data and scanning electron microscopy, which show the materials&#39; morphology and size to be dependent on the reaction conditions. Microwave-assisted reactions produce silica nanoparticles with roughened textured surfaces that are atypical for silica sols produced by St&#246;ber&#39;s methods, which have smooth surfaces.

Silica nanoparticles were prepared using acid-catalysis of a siloxane precursor and microwave-assisted synthetic techniques resulting in the controlled growth of nanomaterials ranging from 30-250 nm in diameter. The growth dynamics can be controlled by varying the initial silicic acid concentration, time of the reaction, and temperature of reaction.

Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle ...

Exploring the Radical Nature of a Carbon Surface by Electron Paramagnetic Resonance and a Calibrated Gas Flow

While the first Electron Paramagnetic Resonance (EPR) studies regarding the effects of oxidation on the structure and stability of carbon radicals date back to the early 1980s the focus of these early papers primarily characterized the changes to the structures under extremely harsh conditions (pH or temperature)1-3. It is also known that paramagnetic molecular oxygen undergoes a Heisenberg spin exchange interaction with stable radicals that extremely broadens the EPR signal4-6. Recently, we reported interesting results where this interaction of molecular oxygen with a certain part of the existing stable radical structure can be reversibly affected simply by flowing a diamagnetic gas through the carbon samples at STP7. As flows of He, CO2, and N2 had a similar effect these interactions occur at the surface area of the macropore system.
This manuscript highlights the experimental techniques, work-up, and analysis towards affecting the existing stable radical nature in the carbon structures. It is hoped that it will help towards further development and understanding of these interactions in the community at large.

Stable radicals that are present in carbon substrates interact with paramagnetic oxygen through a Heisenberg spin exchange. This interaction can be significantly reduced under STP conditions by flowing a diamagnetic gas over the carbon system. This manuscript describes a simple method to characterize the nature of those radicals.

While the first Electron Paramagnetic Resonance (EPR) studies regarding the effects of oxidation on the structure and stability of carbon radicals date ...

Synthesis and Catalytic Performance of Gold Intercalated in the Walls of Mesoporous Silica

As a promising catalytically active nano reactor, gold nanoparticles intercalated in mesoporous silica (GMS) were successfully synthesized and properties of the materials were investigated. We used a one pot sol-gel approach to intercalate gold nano particles in the walls of mesoporous silica. To start with the synthesis, P123 was used as template to form micelles. Then TESPTS was used as a surface modification agent to intercalate gold nano particles. Following this process, TEOS was added in as a silica source which underwent a polymerization process in acid environment. After hydrothermal processing and calcination, the final product was acquired. Several techniques were utilized to characterize the porosity, morphology and structure of the gold intercalated mesoporous silica. The results showed a stable structure of mesoporous silica after gold intercalation. Through the oxidation of benzyl alcohol as a benchmark reaction, the GMS materials showed high selectivity and recyclability.

Here, we present a protocol with a sol-gel process to synthesize gold intercalated in the walls of mesoporous materials (GMS), which is confirmed to possess a mesoporous matrix with gold intercalated in the walls imparting great stability and recyclability.

As a promising catalytically active nano reactor, gold nanoparticles intercalated in mesoporous silica (GMS) were successfully synthesized and properties ...

Transport of Surface-modified Carbon Nanotubes through a Soil Column

Carbon nanotubes (CNTs) are widely manufactured nanoparticles, which are being utilized in a number of consumer products, such as sporting goods, electronics and biomedical applications. Due to their accelerating production and use, CNTs constitute a potential environmental risk if they are released to soil and groundwater systems. It is therefore essential to improve the current understanding of environmental fate and transport of CNTs. The transport and retention of CNTs in both natural and artificial media have been reported in literature, but the findings widely vary and are thus not conclusive. There are a number of physical and chemical parameters responsible for variation in retention and transport. In this study, a complete procedure of selected multiwalled carbon nanotubes (MWCNTs) is presented starting from their surface modification to a complete set of laboratory column experiments at critical physical and chemical scenarios. Results indicate that the stability of the commercially available MWCNTs are critical with their attached surface functional group which can also influence the transport and retention of MWCNT through the surrounding medium.

Surface properties of a nanoparticle are important for their interaction with the surrounding medium. Therefore the surface modification of carbon nanotubes can be critical for their transport and retention through porous media. Here, lab scale column experiments are used to understand the possible transport and retention of these nanoparticles.

Carbon nanotubes (CNTs) are widely manufactured nanoparticles, which are being utilized in a number of consumer products, such as sporting goods, ...

Preparation of Carbon Nanosheets at Room Temperature

Amphiphilic molecules equipped with a reactive, carbon-rich "oligoyne" segment consisting of conjugated carbon-carbon triple bonds self-assemble into defined aggregates in aqueous media and at the air-water interface. In the aggregated state, the oligoynes can then be carbonized under mild conditions while preserving the morphology and the embedded chemical functionalization. This novel approach provides direct access to functionalized carbon nanomaterials. In this article, we present a synthetic approach that allows us to prepare hexayne carboxylate amphiphiles as carbon-rich siblings of typical fatty acid esters through a series of repeated bromination and Negishi-type cross-coupling reactions. The obtained compounds are designed to self-assemble into monolayers at the air-water interface, and we show how this can be achieved in a Langmuir trough. Thus, compression of the molecules at the air-water interface triggers the film formation and leads to a densely packed layer of the molecules. The complete carbonization of the films at the air-water interface is then accomplished by cross-linking of the hexayne layer at room temperature, using UV irradiation as a mild external stimulus. The changes in the layer during this process can be monitored with the help of infrared reflection-absorption spectroscopy and Brewster angle microscopy. Moreover, a transfer of the carbonized films onto solid substrates by the Langmuir-Blodgett technique has enabled us to prove that they were carbon nanosheets with lateral dimensions on the order of centimeters.

We present the synthesis of an amphiphilic hexayne and its use in the preparation of carbon nanosheets at the air-water interface from a self-assembled monolayer of these reactive, carbon-rich molecular precursors.

Amphiphilic molecules equipped with a reactive, carbon-rich "oligoyne" segment consisting of conjugated carbon-carbon triple bonds self-assemble into ...

TiO2-coated Hollow Glass Microspheres with Superhydrophobic and High IR-reflective Properties Synthesized by a Soft-chemistry Method

This manuscript proposes a soft-chemistry method to develop superhydrophobic and highly IR-reflective hollow glass microspheres (HGM). The anatase TiO2 and a superhydrophobic agent were coated on the HGM surface in one step. TBT and PFOTES were selected as the Ti source and the superhydrophobic agent, respectively. They were both coated on the HGM, and after the hydrothermal process, the TBT turned to anatase TiO2. In this way, a PFOTES/TiO2-coated HGM (MCHGM) was prepared. For comparison, PFOTES single-coated HGM (F-SCHGM) and TiO2 single-coated HGM (Ti-SCHGM) were synthesized as well. The PFOTES and TiO2 coatings on the HGM surface were demonstrated through X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive detector (EDS) characterizations. The MCHGM showed a higher contact angle (153&#176;) but a lower sliding angle (16&#176;) than F-SCHGM, with a contact angle of 141.2&#176; and a sliding angle of 67&#176;. In addition, both Ti-SCHGM and MCHGM displayed similar IR reflectivity values, which were about 5.8% higher than the original HGM and F-SCHGM. Also, the PFOTES coating barely changed the thermal conductivity. Therefore, F-SCHGM, with a thermal conductivity of 0.0479 W/(m&#183;K), was quite like the original HGM, which was 0.0475 W/(m&#183;K). MCHGM and Ti-SCHGM were also similar. Their thermal conductivity values were 0.0543 W/(m&#183;K) and 0.0543 W/(m&#183;K), respectively. The TiO2 coating slightly increased the thermal conductivity, but with the increase in reflectivity, the overall heat-insulation property was enhanced. Finally, since the IR-reflecting property is provided by the HGM coating, if the coating is fouled, the reflectivity decreases. Therefore, with the superhydrophobic coating, the surface is protected from fouling, and its lifetime is also prolonged.

TiO2-coated Hollow Glass Microspheres with Superhydrophobic and High IR-reflective Properties Synthesized by a Soft-chemistry Method

This manuscript proposes a soft-chemistry method to synthesize superhydrophobic, TiO2-coated hollow glass microspheres (HGM) with high IR-reflective properties.

This manuscript proposes a soft-chemistry method to develop superhydrophobic and highly IR-reflective hollow glass microspheres (HGM). The anatase TiO2 ...

Time-resolved Photophysical Characterization of Triplet-harvesting Organic Compounds at an Oxygen-free Environment Using an iCCD Camera

Here, we present a sensible method of the acquisition and analysis of time-resolved photoluminescence using an ultrafast iCCD camera. This system enables the acquisition of photoluminescence spectra covering the time regime from nanoseconds up to 0.1 s. This enables us to follow the changes in the intensity (decay) and emission of the spectra over time. Using this method, it is possible to study diverse photophysical phenomena, such as the emission of phosphorescence, and the contributions of prompt and delayed fluorescence in molecules showing thermally activated delayed fluorescence (TADF). Remarkably, all spectra and decays are obtained in a single experiment. This can be done for solids (thin film, powder, crystal) and liquid samples, where the only limitations are the spectral sensitivity of the camera and the excitation wavelength (532 nm, 355 nm, 337 nm, and 266 nm). This technique is, thus, very important when investigating the excited state dynamics in organic emitters for their application in organic light-emitting diodes and other areas where triplet harvesting is of paramount importance. Since triplet states are strongly quenched by oxygen, emitters with efficient TADF luminescence, or those showing room temperature phosphorescence (RTP), must be correctly prepared in order to remove any dissolved oxygen from solutions and films. Otherwise, no long-lived emission will be observed. The method of degassing solid samples as presented in this work is basic and simple, but the degassing of liquid samples creates additional difficulties and is particularly interesting. A method of minimizing solvent loss and changing the sample concentration, while still enabling to remove oxygen in a very efficient and a repeatable manner, is presented in this work.

Here, we present a method of the spectroscopic characterization of organic molecules by means of time-resolved photoluminescence spectroscopy on the nanosecond-to-millisecond timescale in oxygen-free conditions. Methods to efficiently remove oxygen from the samples and, thus, limit luminescence quenching are also described.

Here, we present a sensible method of the acquisition and analysis of time-resolved photoluminescence using an ultrafast iCCD camera. This system enables ...

Raman and IR Spectroelectrochemical Methods as Tools to Analyze Conjugated Organic Compounds

In the presented work, two spectroelectrochemical techniques are discussed as tools for the analysis of the structural changes occurring in the molecule on the vibrational level of energy. Raman and IR spectroelectrochemistry can be used for advanced characterization of the structural changes in the organic electroactive compounds. Here, the step-by-step analysis by means of Raman and IR spectroelectrochemistry is shown. Raman and IR spectroelectrochemical techniques provide complementary information about structural changes occurring during an electrochemical process, i.e. allows for the investigation of redox processes and their products. The examples of IR and Raman spectroelectrochemical analysis are presented, in which the products of the redox reactions, both in solution and solid state, are identified.

A protocol of step-by-step Raman and IR spectroelectrochemical analysis is presented.

In the presented work, two spectroelectrochemical techniques are discussed as tools for the analysis of the structural changes occurring in the molecule ...

Preparation of Functional Silica Using a Bioinspired Method

The goal of the protocols described herein is to synthesize bioinspired silica materials, perform enzyme encapsulation therein, and partially or totally purify the same by acid elution. By combining sodium silicate with a polyfunctional bioinspired additive, silica is rapidly formed at ambient conditions upon neutralization. 
The effect of neutralization rate and biomolecule addition point on silica yield are investigated, and biomolecule immobilization efficiency is reported for varying addition point. In contrast to other porous silica synthesis methods, it is shown that the mild conditions required for bioinspired silica synthesis are fully compatible with the encapsulation of delicate biomolecules. Additionally, mild conditions are used across all synthesis and modification steps, making bioinspired silica a promising target for the scale-up and commercialization as both a bare material and active support medium.
The synthesis is shown to be highly sensitive to conditions, i.e., the neutralization rate and final synthesis pH, however tight control over these parameters is demonstrated through the use of auto titration methods, leading to high reproducibility in reaction progression pathway and yield. 
Therefore, bioinspired silica is an excellent active material support choice, showing versatility towards many current applications, not limited to those demonstrated here, and potency in future applications.

Here, we present a protocol to synthesize bioinspired silica materials and immobilize enzymes therein. Silica is synthesized by combining sodium silicate and an amine &#39;additive&#39;, which neutralize at a controlled rate. Material properties and function can be altered either by in situ enzyme immobilization or post-synthetic acid elution of encapsulated additives.

The goal of the protocols described herein is to synthesize bioinspired silica materials, perform enzyme encapsulation therein, and partially or totally ...

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

With this protocol, a well-defined singlesite silica-supported heterogeneous catalyst [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is designed and prepared according to the methodology developed by surface organometallic chemistry (SOMC). In this framework, catalytic cycles can be determined by isolating crucial intermediates. All air-sensitive materials are handled under inert atmosphere (using gloveboxes or a Schlenk line) or high vacuum lines (HVLs, &#60;10-5 mbar). The preparation of SiO2-700 (silica dehydroxylated at 700 &#176;C) and subsequent applications (the grafting of complexes and catalytic runs) requires the use of HVLs and double-Schlenk techniques. Several well-known characterization methods are used, such as Fourier-transform infrared spectroscopy (FTIR), elemental microanalysis, solid-state nuclear magnetic resonance spectroscopy (SSNMR), and state-of-the-art dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP-SENS). FTIR and elemental microanalysis permit scientists to establish the grafting and its stoichiometry. 1H and 13C SSNMR allows the structural determination of the hydrocarbon ligands coordination sphere. DNP SENS is an emerging powerful technique in solid characterization for the detection of poorly sensitive nuclei (15N, in our case). SiO2-700 is treated with about one equivalent of the metal precursor compared to the amount of surface silanol (0.30 mmol&#183;g-1) in pentane at room temperature. Then, volatiles are removed, and the powder samples are dried under dynamic high vacuum to afford the desired materials [(&#8801;Si-O-)Hf(&#951;2&#960;-MeNCH2)(&#951;1-NMe2)(&#951;1-HNMe2)]. After a thermal treatment under high vacuum, the grafted complex is converted into metal imido silica complex [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)]. [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] effectively promotes the metathesis of imines, using the combination of two imine substrates, N-(4-phenylbenzylidene)benzylamine, or N-(4-fluorobenzylidene)-4-fluoroaniline, with N-benzylidenetert-butylamine as substrates. A significantly lower conversion is observed with the blank runs; thus, the presence of the imido group in [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is correlated to the catalytic performance.

A new group IV metal catalyst for imine metathesis is prepared by grafting amine metal complex onto dehydroxylated silica. Surface metal fragments are characterized using FT-IR, elemental microanalysis, and solid-state NMR spectroscopy. Further dynamic nuclear polarization surface enhanced NMR spectroscopy experiments complement the determination of the coordination sphere.

With this protocol, a well-defined singlesite silica-supported heterogeneous catalyst [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is designed and prepared ...