Name: synthesis method for cellulose nanofiber biotemplated palladium composite aerogels
Uploaded: 2019-05-09T13:00:00
Description: Watch this Scientific Journal Video about Synthesis Method for Cellulose Nanofiber Biotemplated Palladium Composite Aerogels at JoVE.com

作者感谢美国陆军贝内特实验室的斯蒂芬·巴托卢奇博士和约书亚·莫雷尔博士使用他们的扫描电子显微镜。这项工作得到了美国西点军校的教师发展研究基金赠款的支持。

注意:使用前请查阅所有相关的安全数据表 (SDS)。执行化学反应时,请使用适当的安全实践,包括使用烟罩和个人防护设备 (PPE)。氢气的快速演化会导致反应管中的高压,导致瓶盖爆裂,溶液喷出。确保反应管保持打开状态,并指向远离实验者,如协议中规定的那样。
1. 纤维素纳米纤维水凝胶制备
<ol><li>纤维素纳米纤维溶液的制备:通过将1.5克的Carboxy甲基纤维化纳米纤维与50 mL的去离?...

<ol>
	<li>Kistler, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coherent+Expanded+Aerogels+and+Jellies.">Coherent Expanded Aerogels and Jellies.</a> Nature. 127, 741 (1931).</li><li>Du, A., Zhou, B., Zhang, Z., Shen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Special+Material+or+a+New+State+of+Matter:+A+Review+and+Reconsideration+of+the+Aerogel.">A Special Material or a New State of Matter: A Review and Reconsideration of the Aerogel.</a> Materials. 6 (3), 941 (2013).</li><li>Tappan, B. C., Steiner, S. A., Luther, E. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoporous+Metal+Foams.">Nanoporous Metal Foams.</a> Angewandte Chemie International Edition. 49 (27), 4544-4565 (2010).</li><li>Bigall, N. 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=Hydrogels+and+Aerogels+from+Noble+Metal+Nanoparticles.">Hydrogels and Aerogels from Noble Metal Nanoparticles.</a> Angewandte Chemie International Edition. 48 (51), 9731-9734 (2009).</li><li>Ranmohotti, K. G. S., Gao, X., Arachchige, I. U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Salt-Mediated+Self-Assembly+of+Metal+Nanoshells+into+Monolithic+Aerogel+Frameworks.">Salt-Mediated Self-Assembly of Metal Nanoshells into Monolithic Aerogel Frameworks.</a> Chemistry of Materials. 25 (17), 3528-3534 (2013).</li><li>Gao, X., Esteves, R. J., Luong, T. T. H., Jaini, R., Arachchige, I. U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxidation-Induced+Self-Assembly+of+Ag+Nanoshells+into+Transparent+and+Opaque+Ag+Hydrogels+and+Aerogels.">Oxidation-Induced Self-Assembly of Ag Nanoshells into Transparent and Opaque Ag Hydrogels and Aerogels.</a> Journal of the American Chemical Society. 136 (22), 7993-8002 (2014).</li><li>Herrmann, A. -. K., 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=Multimetallic+Aerogels+by+Template-Free+Self-Assembly+of+Au,+Ag,+Pt,+and+Pd+Nanoparticles.">Multimetallic Aerogels by Template-Free Self-Assembly of Au, Ag, Pt, and Pd Nanoparticles.</a> Chemistry of Materials. 26 (2), 1074-1083 (2014).</li><li>Ding, Y., Chen, M., Erlebacher, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metallic+Mesoporous+Nanocomposites+for+Electrocatalysis.">Metallic Mesoporous Nanocomposites for Electrocatalysis.</a> Journal of the American Chemical Society. 126 (22), 6876-6877 (2004).</li><li>Liu, W., 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=High-Performance+Electrocatalysis+on+Palladium+Aerogels.">High-Performance Electrocatalysis on Palladium Aerogels.</a> Angewandte Chemie International Edition. 51 (23), 5743-5747 (2012).</li><li>Shafaei Douk, A., Saravani, H., Noroozifar, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+assembly+of+building+blocks+for+the+fabrication+of+Pd+aerogel+as+a+high+performance+electrocatalyst+toward+ethanol+oxidation.">Three-dimensional assembly of building blocks for the fabrication of Pd aerogel as a high performance electrocatalyst toward ethanol oxidation.</a> Electrochimica Acta. 275, 182-191 (2018).</li><li>Burpo, F. J., 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=Direct+solution-based+reduction+synthesis+of+Au,+Pd,+and+Pt+aerogels.">Direct solution-based reduction synthesis of Au, Pd, and Pt aerogels.</a> Journal of Materials Research. 32 (22), 4153-4165 (2017).</li><li>Burpo, F. J., 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=A+Rapid+Synthesis+Method+for+Au,+Pd,+and+Pt+Aerogels+Via+Direct+Solution-Based+Reduction.">A Rapid Synthesis Method for Au, Pd, and Pt Aerogels Via Direct Solution-Based Reduction.</a> JoVE. (136), e57875 (2018).</li><li>Qin, G. W., 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=A+Facile+and+Template-Free+Method+to+Prepare+Mesoporous+Gold+Sponge+and+Its+Pore+Size+Control.">A Facile and Template-Free Method to Prepare Mesoporous Gold Sponge and Its Pore Size Control.</a> The Journal of Physical Chemistry C. 112 (28), 10352-10358 (2008).</li><li>Hench, L. L., West, J. 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+Sol-Gel+Process.">The Sol-Gel Process.</a> Chemical Reviews. 90 (1), 33-72 (1990).</li><li>Sotiropoulou, S., Sierra-Sastre, Y., Mark, S. S., Batt, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biotemplated+Nanostructured+Materials.">Biotemplated Nanostructured Materials.</a> Chemistry of Materials. 20 (3), 821-834 (2008).</li><li>Huang, J., 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=Bio-inspired+synthesis+of+metal+nanomaterials+and+applications.">Bio-inspired synthesis of metal nanomaterials and applications.</a> Chemical Society Reviews. 44 (17), 6330-6374 (2015).</li><li>Burpo, F. J., Mitropoulos, A. N., Nagelli, E. A., Ryu, M. Y., Palmer, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gelatin+biotemplated+platinum+aerogels.">Gelatin biotemplated platinum aerogels.</a> MRS Advances. 10, 1-6 (2018).</li><li>Jarvis, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellulose+stacks+up.">Cellulose stacks up.</a> Nature. 426, 611 (2003).</li><li>Sir&#243;, I., Plackett, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfibrillated+cellulose+and+new+nanocomposite+materials:+a+review.">Microfibrillated cellulose and new nanocomposite materials: a review.</a> Cellulose. 17 (3), 459-494 (2010).</li><li>Dufresne, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanocellulose:+a+new+ageless+bionanomaterial.">Nanocellulose: a new ageless bionanomaterial.</a> Materials Today. 16 (6), 220-227 (2013).</li><li>Grishkewich, N., Mohammed, N., Tang, J., Tam, K. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+in+the+application+of+cellulose+nanocrystals.">Recent advances in the application of cellulose nanocrystals.</a> Current Opinion in Colloid &amp; Interface Science. 29, 32-45 (2017).</li><li>Eyley, S., Thielemans, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+modification+of+cellulose+nanocrystals.">Surface modification of cellulose nanocrystals.</a> Nanoscale. 6 (14), 7764-7779 (2014).</li><li>Missoum, K., Belgacem, M., Bras, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanofibrillated+Cellulose+Surface+Modification.">Nanofibrillated Cellulose Surface Modification.</a> A Review. Materials. 6 (5), 1745 (2013).</li><li>Li, Z., Yao, C., Wang, F., Cai, Z., Wang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellulose+nanofiber-templated+three-dimension+TiO2+hierarchical+nanowire+network+for+photoelectrochemical+photoanode.">Cellulose nanofiber-templated three-dimension TiO2 hierarchical nanowire network for photoelectrochemical photoanode.</a> Nanotechnology. 25 (50), 504005 (2014).</li><li>Hal Koga, ., 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=Uniformly+connected+conductive+networks+on+cellulose+nanofiber+paper+for+transparent+paper+electronics.">Uniformly connected conductive networks on cellulose nanofiber paper for transparent paper electronics.</a> Npg Asia Materials. 6, 93 (2014).</li><li>Fal Burpo, ., 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=Cellulose+Nanofiber+Biotemplated+Palladium+Composite+Aerogels.">Cellulose Nanofiber Biotemplated Palladium Composite Aerogels.</a> Molecules. 23 (6), 1405 (2018).</li><li>Gu, J., Hu, C., Zhang, W., Dichiara, A. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reagentless+preparation+of+shape+memory+cellulose+nanofibril+aerogels+decorated+with+Pd+nanoparticles+and+their+application+in+dye+discoloration.">Reagentless preparation of shape memory cellulose nanofibril aerogels decorated with Pd nanoparticles and their application in dye discoloration.</a> Applied Catalysis B: Environmental. 237, 482-490 (2018).</li><li>Coates, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=in+A+Practical+Approach.">in A Practical Approach.</a> In Encyclopedia of Analytical Chemistry .doi:10.1002/9780470027318.a5606 (ed. , (2006).</li><li>Sal Wang, ., 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=Cellulose+nanofiber-assisted+dispersion+of+cellulose+nanocrystals@polyaniline+in+water+and+its+conductive+films).">Cellulose nanofiber-assisted dispersion of cellulose nanocrystals@polyaniline in water and its conductive films).</a> RSC Advances. 6 (12), 10168-10174 (2016).</li><li>Grabarek, Z., Gergely, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zero-length+crosslinking+procedure+with+the+use+of+active+esters.">Zero-length crosslinking procedure with the use of active esters.</a> Analytical Biochemistry. 185 (1), 131-135 (1990).</li><li>Shabanpour, B., Kazemi, M., Ojagh, S. M., Pourashouri, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bacterial+cellulose+nanofibers+as+reinforce+in+edible+fish+myofibrillar+protein+nanocomposite+films.">Bacterial cellulose nanofibers as reinforce in edible fish myofibrillar protein nanocomposite films.</a> International Journal of Biological Macromolecules. 117, 742-751 (2018).</li><li>Brunauer, B., Emmett, P., Teller, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorption+of+gases+in+multimolecular+layers.">Adsorption of gases in multimolecular layers.</a> Journal of the American Chemical Society. 60, (1938).</li><li>Barrett, E., Joyner, L., Halenda, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+determination+of+pore+volume+and+area+distributions+in+porous+substances.">The determination of pore volume and area distributions in porous substances.</a> I. Computations. 73, (1951).</li></ol>

这里介绍的贵金属纤维素纳米纤维生物模板气凝胶合成方法,使气凝胶复合材料具有稳定的金属成分。离心后压实纤维纳米纤维的共价交联导致水凝胶在随后的氧化铝在氧化铝的合成步骤中具有机械的持久性,即钠的电平衡、电化学还原、喷皮、溶剂交换,和超临界干燥。水凝胶稳定性在电化学还原步骤中至关重要,因为还原剂溶液的浓度高(2MNaBH 4),并因此产生猛烈的氢进化。本研究中使用的?...

基斯特勒首先报道的气凝胶,提供比散装材料1、2、3密度低的多孔结构。贵金属气凝胶因其在功率和能源、催化和传感器应用方面的潜力而引起了科学界的兴趣。贵金属气凝胶最近通过两种基本策略合成。一种策略是诱导预先形成的纳米粒子4、5、6、7的凝聚。纳米粒子的溶胶凝聚可以由链接分子驱动,溶液离子强度的变化,或简单的纳米粒子表面自由能量最小化7,8,9。另一个策略是从金属前体溶液9、10、11、12、13的单一还原步骤中形成气凝胶。这种方法还用于形成双金属和合金贵金属气凝胶。第一种策略通常很慢,可能需要长达数周的纳米粒子凝聚14。直接还原方法虽然通常比较快,但宏观气凝胶单体的形状控制较差。
一种可能的综合方法,以解决挑战与控制惰性金属气凝胶宏观形状和纳米结构是采用生物温度15。生物模板利用从胶原蛋白、明胶、DNA、病毒到纤维素等生物分子,为纳米结构的合成提供一个形状导向模板,由此产生的金属纳米结构具有生物模板分子16,17。纤维素纳米纤维作为生物模板很有吸引力,因为纤维素材料具有高天然丰度,其高纵横比线性几何形状,以及化学功能化其葡萄糖单体的能力 18,19 20,21,22,23.纤维素纳米纤维 (CNF) 已用于合成用于光阳极24的三维 TiO2纳米线、用于透明纸电子25的银纳米线 25 和用于催化的铂气凝胶复合材料26.此外,TEMPO氧化纤维素纳米纤维已被用作生物模板和还原剂在制备铂装饰CNF气凝胶27。
这里提出了一种合成纤维素纳米纤维生物模板复合气凝胶的方法。形状控制较差的易碎气凝胶适用于一系列贵金属气凝胶合成方法。用于形成共价水凝胶的Carboxy甲基化纤维素纳米纤维(CNFs)允许减少CNF上的金属离子,如金晶,从而在超临界干燥后控制纳米结构和宏观气凝胶单片形状。Carboxy甲基化纤维素纳米纤维交联是使用1-乙基-3-(3-二甲基氨基丙基)盐酸甲二酰胺(EDC)在乙烯二胺作为CNF之间的链接分子的情况下实现的。CNF 水凝胶在整个合成步骤中保持其形状,包括共价交联、与前体离子的平衡、高浓度还原剂的金属还原、水中的沉淀、乙醇溶剂交换和 CO2超临界干燥。前体子浓度变化允许通过直接减少的气凝胶金属含量来控制最终气凝胶的金属含量,而不是依赖于在溶胶方法中使用的预成型纳米粒子的相对缓慢的凝聚。该方法以扩散为基础,将化学物种引入和去除水凝胶,适用于较小的散装几何形状和薄膜。纤维素纳米纤维-铂复合气凝胶的特征,带扫描电子显微镜、X 射线衍射学、热重力分析、氮气吸附、电化学阻抗光谱和循环伏特测量表示高表面积,金属化的多孔结构。

<table border="0" cellpadding="0" cellspacing="0" style="width:826px;" width="825">
	<tbody>
		<tr height="62">
			<td height="62" style="height:63px;width:295px;">0.5 mm platinum wire electrode</td>
			<td style="width:132px;">BASi</td>
			<td style="width:123px;">MW-4130</td>
			<td style="width:277px;">Used for auxillery electrode and separately for lacquer coating and use as a working electrode</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:295px;">1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC)</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td style="width:123px;">&#160;1892-57-5</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:295px;">2-(N-morpholino)ethanesulfonic acid (MES)</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td>117961-21-4&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Ag/AgCl (3M NaCl) Reference Electrode</td>
			<td style="width:132px;">BASi</td>
			<td style="width:123px;">MF-2052</td>
			<td></td>
		</tr>
		<tr height="83">
			<td height="83" style="height:84px;width:295px;">Carboxymethyl cellulose, TEMPO Cellulose Nanofibrils, Dry Powder</td>
			<td style="width:132px;">University of Maine Process Development Center</td>
			<td style="width:123px;">No 8</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Ethanol, 200 proof</td>
			<td style="width:132px;">PHARMCO-AAPER</td>
			<td style="width:123px;">241000200</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Ethylenediamine</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td style="width:123px;">&#160;107-15-3</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:295px;">Fourier-Transform Infrared (FTIR) Spectrometer, Frontier</td>
			<td style="width:132px;">Perkin Elmer</td>
			<td style="width:123px;">L1280044</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Hydrochloric Acid</td>
			<td style="width:132px;">CORCO</td>
			<td style="width:123px;">7647-01-0</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:25px;width:295px;">Na2PdCl4</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td style="width:123px;">13820-40-1</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:25px;width:295px;">NaBH4</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td style="width:123px;">16940-66-2</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:25px;width:295px;">Pd(NH3)4Cl2</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td style="width:123px;">13933-31-8</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Potentiostat</td>
			<td style="width:132px;">Biologic-USA</td>
			<td style="width:123px;">VMP-3</td>
			<td>Electrochemical analysis-EIS, CV</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:295px;">Scanning Electron Mciroscope (SEM) Helios 600 Nanolab</td>
			<td style="width:132px;">ThermoFisher Scientific</td>
			<td style="width:123px;"></td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:25px;width:295px;">Supercritical Dryer</td>
			<td style="width:132px;">Leica</td>
			<td style="width:123px;">EM CPD300</td>
			<td>Aerogel supercritical drying with CO2</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Surface and Pore Analyzer</td>
			<td style="width:132px;">Quantachrome</td>
			<td style="width:123px;">NOVA 4000e</td>
			<td>Nitrogen gas adsorption</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">Thermal Gravimetric Analysis</td>
			<td style="width:132px;">TA instruments</td>
			<td style="width:123px;">TGA Q500</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:295px;">Ultrasonic Cleaner</td>
			<td style="width:132px;">MTI</td>
			<td style="width:123px;">EQ-VGT-1860QTD</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:295px;">XRD</td>
			<td style="width:132px;">PanAlytical</td>
			<td style="width:123px;">Empyrean</td>
			<td>X-ray diffractometry</td>
		</tr>
	</tbody>
</table>

synthesis method for cellulose nanofiber biotemplated palladium composite aerogels

本文提出了一种合成纤维素纳米纤维生物模板化复合气凝胶的方法。惰性金属气凝胶合成方法往往导致脆弱的气凝胶形状控制不良。使用Carboxy甲基化纤维素纳米纤维(CNFs)形成共价粘结水凝胶,可减少金属离子,如在CNF上,在上临界后控制纳米结构和宏观气凝胶单体形状干燥。在存在乙烯二胺的情况下,使用1-乙基-3-(3-二甲基氨基丙基)盐酸甲酰胺(EDC)实现碳甲基化纤维化纳米纤维的交联。CNF 水凝胶在整个合成步骤中保持其形状,包括共价交联、与前体离子的平衡、高浓度还原剂的金属还原、水中的沉淀、乙醇溶剂交换和 CO2超临界干燥。改变前体钚的电浓度,可以通过直接的电子化学还原来控制最终气凝胶复合材料中的金属含量,而不是依赖于其他预成型纳米粒子的相对缓慢的凝聚溶胶技术。该方法以扩散为基础,将化学物种引入和去除水凝胶,适用于较小的散装几何形状和薄膜。纤维素纳米纤维-铂复合气凝胶的特征,带扫描电子显微镜、X 射线衍射学、热重力分析、氮气吸附、电化学阻抗光谱和循环伏特测量表示具有高表面积、金属化的多孔结构。

图1描述了在乙烯二胺存在的情况下将纤维素纳米纤维与EDC共价交联的方案。EDC 交联导致卡博基和原胺功能组之间的酰胺键。鉴于Carboxy甲基纤维素纳米纤维仅具有用于交联的甲酰基组,因此,存在二胺链接分子(如乙烯二胺)对于通过两个酰胺键将两个相邻的CNF共价连接至关重要。为了确认交联,图2显示了与CNF水凝胶相比,在存在乙烯...

Watch this Scientific Journal Video about Synthesis Method for Cellulose Nanofiber Biotemplated Palladium Composite Aerogels at JoVE.com

Synthesis Method for Cellulose Nanofiber Biotemplated Palladium Composite Aerogels

提出了纤维素纳米纤维生物模板复合气凝胶的合成方法。由此产生的复合气凝胶材料为催化、传感和氢气储存应用提供了潜力。

纤维素纳米纤维生物模板复合气凝胶的合成方法

Here, a method to synthesize cellulose nanofiber biotemplated palladium composite aerogels is presented. Noble metal aerogel synthesis methods often ...

该方法使用纤维素纳米纤维生物聚合物共价水凝胶实现铂金气凝胶复合材料，可推广到各种生物聚合物模板和金属中。这种复合气凝胶合成方法使用纤维素纳米纤维作为生物模板，以实现对帕利姆金属纳米结构和大微氧体整体形状的控制。生物镀金属气凝胶的形状控制和机械完整性应有助于催化、储能和传感的应用。该方法可应用于进一步开发生物聚合物碳金属模板，实现复合气凝胶材料三维纳米结构的更好控制。要准备纤维素纳米纤维溶液，首先将1.5克碳氧甲基纤维素纳米纤维与50毫升去硫化水混合。摇动后，将溶液旋转一分钟，随后在环境温度下在沐浴声波器中孵育24小时，以确保完全混合。第二天早上，加入0.959克EDC和0.195克 MES 缓冲液至 2.833 毫升去维化水。然后，将最终体积调整为 10 毫升，用一摩尔盐酸和去维水将 pH 调为 4.5。接下来，将 3%纤维素纳米纤维溶液的 0.25 毫升转移到 6 个微富管中，通过离心沉淀纳米纤维。使用移液器吸气压压的纳米纤维上方的过量水，同时避免与顶部表面接触。在每个微混管中压实的纤维素纳米纤维之上加入一毫升EDC和二胺交联溶液。等待至少 24 小时，让交联溶液通过凝胶扩散，以交联纤维素纳米纤维。然后，从微混液管中吸出交联溶液上流剂，将微混液管浸入一升脱硫水中至少24小时，盖打开，从纳米纤维水凝胶中去除多余的交联溶液。第二天，在脱硫水中加入约0.5毫升的3%纤维素纳米纤维溶液，加入四联变红外光谱仪的样品阶段，扫描650至4000厘米的透射率。为了准备铂溶液，在将溶液稀释至1毫升，在一、10、50、100、500和1000毫升浓度下，将氯化铵的10毫升或10毫升。接下来，在单个纤维素纳米纤维水凝胶样品的顶部加入每一毫升的稀释剂，使铂溶液在水凝胶内平衡24小时。第二天，在烟罩中，将60毫升的双摩尔二摩尔钠和移液器制成6个15毫升锥形管，然后将平衡的纤维素纳米纤维水凝胶管转移到烟气罩中。佩戴适当的个人防护设备，倒置一根微离心管，轻轻敲击管内去除水凝胶，用扁平钳子将水凝胶转移到一管波罗氢钠中。24 小时后，将每个还原的水凝胶转移到第二个 24 小时、0.5 摩尔氢化钠还原溶液中，然后再将纤维素纳米纤维-铂金复合凝胶在 50 毫升的去离子水中重新入质。12 小时后更换去化水，让凝胶至少再冲洗 12 小时。然后，使用扁平钳子将冲洗过的纤维素纳米纤维-铂凝胶转移到连续的 50 毫升体积 25%50%75%和 100%乙醇溶液中，每个溶液至少六小时。最后一次溶剂交换后，用二氧化碳将水凝胶干燥在超临界干燥机中，设定点为35摄氏度，每平方英寸为1200磅。干燥完成后，让腔室平衡至少 12 小时，然后打开干燥器以去除气凝胶。要通过扫描电子显微镜来描述复合气凝胶，请使用剃须刀刀片将每个凝胶切成一到两毫米厚的部分，并使用碳胶带将薄膜样品固定到扫描电子显微镜样品存根上。将存根加载到显微镜上，并使用 15 千伏的初始加速电压和 2.7 至 5.4 皮安的初始束流对样品进行成像。要通过 X 射线衍射分析分析气凝胶，请将纤维素纳米纤维-铂气凝胶放在样品架中，然后将气凝胶的顶部与气凝胶的顶部对齐。然后，执行 X 射线衍射扫描，以 X 射线衍射扫描 2 个 5 度到 90 度的衍射角度，在 45 千伏和 40 毫安铜 K-alpha 辐射下，两个 theta 步长为 0130 度，每步 20 秒。对于热重力分析，请将气凝胶样品放在仪器熔炉中，然后以每分钟 60 毫升流动氮气进行分析，以每分钟 10 度的速度从环境温度加热到 700 摄氏度。对于氮气吸附-吸附，在室温下将样品脱气24小时，然后使用零下196摄氏度的氮气作为测试气体，吸附和吸附时间分别达到60秒和120秒。对于电化学表征，将气凝胶样品浸入 0.5 摩尔硫酸电解质中 24 小时，然后放置一毫米外露尖端与电化学瓶底部气凝胶顶部表面接触的涂漆线。然后，使用带银/氯化银0.5毫米直径铂线辅助计数器电极和涂漆0.5毫米直径的铂工作电极的三电极电池进行电化学阻抗光谱 从一兆赫到一毫赫，具有 10 毫伏正弦波和循环电压，电压范围为负 0.2 至 1.2 伏，扫描速率为 10， 25， 50 毫伏/秒。50 毫伏和 75 毫伏/ 秒。四位转换红外光谱可以执行，如证明确认纤维素纳米纤维水凝胶交联。在这里，在平衡一系列氯化铵或氯化钠浓度之前和之后，共价交联纤维素纳米纤维水凝胶。在这里，减少纤维素纳米纤维-铂凝胶显示之前和之后超临界气凝胶复合干燥。一般来说，气凝胶呈现相互连接的纤维韧带与不断增加的纳米粒子尺寸，通过扫描电子显微镜与增加铂溶液浓度相关。随着铂钠和氢化物的X射线衍射光谱的不断增加，直到光谱在1000毫摩尔时不再可分辨，与扫描电子显微镜观察到的纳米粒子直径的增加有关。热重力光谱分析表明，随着合成铂溶液浓度的增加，纤维素纳米纤维-铂复合气凝胶中的金属含量不断增加。物理吸附数据表明IV型吸附-脱吸等温，表明中孔和大孔结构，巴雷特-乔伊纳-哈伦达孔径分析表明，随着气凝胶铂含量的增加，中孢子的频率会降低。电化学阻抗光谱说明了纤维素纳米纤维-铂复合气凝胶的低电荷转移电阻和双层电容。此外，循环电压扫描显示氢吸附和脱吸电位低于零伏特，以及大于 0.5 伏特的铂的特征氧化和还原峰值。请记住，用水和乙醇的增量浓度冲洗凝胶，因为大浓度差异导致的渗透肿胀可能会破裂水凝胶。将石墨烯和碳纳米管等材料结合到复合生物模板中，可以实现更高的气凝胶机械耐用性和导电性。使用纤维素纳米纤维共价水凝胶实现多孔金属复合气凝胶为各种外形的其他惰性金属和过渡金属材料提供了合成途径。高浓度的水性氢化钠会导致可燃氢气的产生。在通风良好的区域，远离明火，以电化学方法减少样品非常重要。

Research

JoVE Journal

Chemistry

Towards Biomimicking Wood: Fabricated Free-standing Films of Nanocellulose, Lignin, and a Synthetic Polycation

朝仿生学木：纳米纤维素，木质素的装配式自由站立电影和合成聚阳离子

Woody materials are comprised of plant cell walls that contain a layered secondary cell wall composed of structural polymers of polysaccharides and ...

科研

化学

Synthesis of Indoxyl-glycosides for Detection of Glycosidase Activities

的吲哚酚苷的检测糖苷酶活动的合成

Indoxyl glycosides proved to be valuable and versatile tools for monitoring glycosidase activities. Indoxyls are released by enzymatic hydrolysis and are ...

A Simple Method for the Size Controlled Synthesis of Stable Oligomeric Clusters of Gold Nanoparticles under Ambient Conditions

根据环境条件的金纳米粒子的稳定低聚簇的大小控制合成的一种简便方法

Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like ...

Preparation of Biopolymer Aerogels Using Green Solvents

生物聚合物气凝胶制备使用绿色溶剂

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers ...

Hydroquinone Based Synthesis of Gold Nanorods

金纳米棒基于对苯二酚合成

Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the ...

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

钯<em&gt;ñ</em&gt; - 杂环碳烯配合物：苯并咪唑盐的合成和碳 - 碳键合反应中的催化活性

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from ...

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

化学沉淀法合成铌2O5改性高比表面积镍催化剂

We demonstrate a method for the synthesis of NixNb1-xO catalysts with sponge-like and fold-like nanostructures. By varying the Nb:Ni ratio, a series of ...

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction

快速超临界萃取制备催化气凝胶的制备与试验研究

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three ...

Ligand-Mediated Nucleation and Growth of Palladium Metal Nanoparticles

配体介导成核与钯金属纳米粒子的生长

The size, size distribution and stability of colloidal nanoparticles are greatly affected by the presence of capping ligands. Despite the key contribution ...