We are grateful to the Canadian Natural Sciences and Engineering Research Council (RGPIN-2018-06748), the Canadian Foundation for Innovation (229288), the Canadian Institute for Advanced Research (BSE-BERL-162173), and Canada Research Chairs for financial support. This research was undertaken thanks in part to funding from the Canada First Research Excellence Fund, Quantum Materials and Future Technologies Program. We thank Ben Herring at the UBC Shared Instrument Facility for assistance with the GC-MS instrument and method development. We thank Dr. Monika Stolar for contributions to the development and editing of this manuscript. Finally, we thank the entire Berlinguette Group at the University of British Columbia for their continued support and collaboration in studying the membrane reactor.

1. Pd rolling
<ol>
	<li>Clean the Pd wafer bar with a mixture of hexanes using a cotton cloth. 
	CAUTION: Hexane is flammable, a health hazard, an irritant, and environmentally damaging. Work under proper ventilation (i.e., a snorkel or a fume hood).</li>
	<li>Roll the Pd wafer using a manual roller until reaching a thickness of &#8804;150 &#181;m, as determined by a digital micrometer.</li>
	<li>Roll the Pd using an automatic roller to a thickness of 25 &#181;m, as determined by a digital micrometer. Then, cut the resulting Pd into the desired dimensions (e.g., 3.5 cm x 3.5 cm).</li>
</ol>
2. Pd annealing
<ol>
	<li>Load the rolled Pd foils into a muffle oven with an N2 atmosphere.</li>
	<li>Heat the Pd foils starting at 25 &#176;C, and ramp the temperature to 850 &#176;C at a rate of 60 &#176;C/h. Hold the temperature at 850 &#176;C for 1.5 h, and then cool the oven to room temperature at a rate of 60 &#176;C/h.</li>
</ol>
3. Pd cleaning
<ol>
	<li>Prepare a cleaning solution by combining 10 mL of nitric acid, 20 mL of 30% (v/v) hydrogen peroxide, and 10 mL of deionized water. 
	CAUTION: Nitric acid is corrosive, an oxidant, and toxic. Hydrogen peroxide is corrosive, an oxidant, and harmful.</li>
	<li>Submerge the annealed Pd foils in the cleaning solution until the vigorous bubbling subsides or the solution turns yellow (20-30 min).</li>
	<li>Rinse the Pd foils twice with DI water and once with isopropyl alcohol, and then dry with air.</li>
</ol>
4. Reactor assembly (Figure 2, left to right)
<ol>
	<li>Assemble the reactor by sandwiching the Pd membrane between two halves of an electrochemical H-cell.</li>
	<li>Place a chemical-resistant gasket between the left-hand side of the cell and the Pd membrane.</li>
	<li>Place an additional chemical-resistant gasket between the Pd membrane and the right- hand side of the electrochemical cell.</li>
	<li>Seal the resulting cell configuration with a clip.</li>
</ol>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/65098/65098fig02v2.jpg" /> 
Figure 2: An image of the H-cell assembly.&#160;The electrochemical compartment contains 1 M H2SO4&#160;electrolyte; this is where water oxidation occurs. The palladium membrane separates the two halves of the H-cell, and the gaskets provide a leak-free seal. The hydrogenation compartment contains 0.01 M propiophenone in ethanol (EtOH).&#160;<a href="https://www.jove.com/files/ftp_upload/65098/65098fig02largev2.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
5. Pd electrodeposition
<ol>
	<li>Prepare an electroplating solution by dissolving PdCl2 into 1 M HCl to reach a concentration of 15.9 mM. 
	CAUTION: PdCl2 is harmful and corrosive. HCl is corrosive and an irritant.</li>
	<li>Assemble the reactor using a clean Pd foil from step 3.</li>
	<li>Fill the electrochemical compartment of the reactor with 24 mL of the prepared electroplating solution, and leave the hydrogenation compartment empty.</li>
	<li>Place a Pt mesh anode and an Ag/AgCl reference electrode into the solution in the electrochemical compartment.</li>
	<li>Connect the electrodes to a potentiostat, and apply a potential of -0.2 V versus Ag/AgCl to the Pd foil until a charge of 15 C has passed.</li>
	<li>Disassemble the reactor, rinse the resulting Pd membrane twice with deionized water and once with isopropyl alcohol, and then dry the membrane under a stream of air or N2. The Pd membrane will now have a visible deposition of Pd black on the surface that was exposed to the electroplating solution.</li>
</ol>
6. Atm-MS reactor setup
<ol>
	<li>Assemble the reactor as indicated in step 4. Fill the electrochemical compartment with 1 M H2SO4, and fill the hydrogenation compartment with ethanol. Do not add hydrogenation feedstock. 
	CAUTION: H2SO4 is harmful and corrosive. Ethanol is flammable, harmful, and a health hazard.</li>
	<li>Submerge a Pt counter electrode in the electrolyte. Connect the Pt counter electrode and the Pd membrane to a power supply using alligator clips. Connect the Pt counter electrode as the positive electrode and the Pd membrane as the negative electrode.</li>
	<li>Apply a constant current of 25 mA.</li>
</ol>
7. Atm-MS instrument setup
<ol>
	<li>Turn on the power switch on the back of the atm-MS unit, just below the power cord.</li>
	<li>Press the pump button on the front to turn on the pump (it will light up blue when on). Then, turn on the bake jacket (green round switch, the light will come on).</li>
	<li>Turn on the capillary channel to be used (red round switches next to the channels, the light will come on). Check that the channel used is turned on by feeling the tube being heated. 
	NOTE: The green LED next to &#34;vac ok&#34; will come on within a few minutes of turning the pump on. To turn off the system after finishing the experiments, turn off all the switches that have been turned on.</li>
	<li>Connect the hydrogenation cell outlet to the atm-MS capillaries. This connection must be airtight.</li>
</ol>
8. Atm-MS software setup
<ol>
	<li>Click on the Service desktop shortcut. Go to Setup | SEM/Emission Control, and check the boxes for both SEM and emissions. Press OK. Close the service window.</li>
	<li>Click on the Measure shortcut, and go to Sequence | Execute.</li>
	<li>Fill in the following parameters: Measurements = 30, Purge time = 30 s. Press File Manager, and create a folder to save the output data in. These settings will take 30 measurements with a purge time of 30 s between each measurement set; this can be changed if needed.</li>
	<li>The MID measurements file will then open. Select File Management, and open a program to measure the mass spectrometry signal for m/z = 2. This signal corresponds to the ionic current from H2+, the ionized form of hydrogen gas.</li>
	<li>Press OK to start the program. Do not close the measurement window as this will stop the instrument running.</li>
	<li>After the signal has stabilized (1-3 h), disconnect the atm-MS capillary from the hydrogenation compartment, and connect it to the electrochemical compartment.</li>
	<li>Save the data, and terminate the experiment when the signal for the electrochemical compartment has stabilized (about 30 min).</li>
	<li>Calculate the percentage of hydrogen permeation through the Pd membrane using Equation 1.</li>
</ol>
9. Electrochemical hydrogenation
<ol>
	<li>Assemble the reactor according to step 4.</li>
	<li>Fill the electrochemical compartment with 24 mL of 1 M H2SO4.</li>
	<li>Insert a Pt counter electrode into the electrochemical compartment through the counter electrode opening. Connect the Pt counter electrode to the positive terminal of a power supply, and connect the Pd membrane to the negative terminal via Cu tape.</li>
	<li>Apply a galvanostatic current of 25 mA (corresponds to 40 mA/cm2) across the cell for 15 min. The voltage will read between 3 V and 5 V.</li>
	<li>After 15 min has passed, fill the chemical compartment with 24 mL of reaction solution (e.g., 0.01 M propiophenone in ethanol). Maintain the galvanostatic current during reactant addition. 
	NOTE: Sample the initial reaction solution before it is added to the reactor. See step 9.6. 
	CAUTION: Propiophenone is harmful.</li>
	<li>Sample the chemical compartment periodically (e.g., every 15 min) by taking 30 &#181;L of reaction solution from the chemical compartment using a micropipette and dissolving the sample in 1 mL of dichloromethane. Store the samples in GC-MS vials until the reaction is complete. 
	&#8203;CAUTION: Dichloromethane is harmful and a health hazard.</li>
</ol>
10. Gas chromatography-mass spectrometry
<ol>
	<li>Load the sample vials into the autosampling tray.</li>
	<li>Launch the GC-MS software by clicking on the green Masshunter icon.</li>
	<li>Click on Sequence | Edit Sequence to open the sequence editing window. Fill in the desired sample names, vial (position in the autosampling tray), method path, method file, data path, and data file into the chart. Set the sample type to &#34;sample&#34; and the dilution to 1, and ensure that the data file matches the sample name.</li>
	<li>Adjust the method by clicking on Method | Edit Entire Method.
	<ol>
		<li>Ensure both Method information and Instrument acquisition are checked. Click on OK. Add Method comments (if desired).</li>
		<li>Ensure Data Acquisition and Data analysis are checked. Leave every other field blank. Click on OK.</li>
		<li>Ensure that the sample inlet is set to GC and the injection source is set to GC ALS. Check the Use MS box. Ensure that the inlet location is set to Front and the MS is connected to Front. Click on OK.</li>
	</ol>
	</li>
	<li>Under the Inlet tab, ensure the heater temperature is set to 250 &#176;C. Set the pressure to 7.2 psi and the He flow to 23.1 mL/min.</li>
	<li>Under the Oven tab, set the initial temperature to 50 &#176;C, and hold for 1 min. Next, set the ramp rate to 25 &#176;C/min and the temperature to 200 &#176;C, and hold for 0 min. Click on OK.</li>
	<li>Ensure none of the display signals are checked. Click on OK.</li>
	<li>Set the solvent delay to 2.50 min. Click on OK.</li>
	<li>Ensure that the selected monitors include the following: GC oven temperature, GC inlet F temperature, GC inlet F pressure, GC column 2 flow calc, MS EM volts, MS MS source, MS MS quad. Click on OK.</li>
	<li>Save the method under the desired method name.</li>
	<li>Start the sequence by clicking on Sequence | Start Sequence | Run Sequence.</li>
	<li>When the sequence is complete, view the data by opening the Masshunter software and clicking on the file name that was programmed in step 10.3.</li>
	<li>Identify the product peaks by clicking on Spectrum | Library search report to compare the acquired mass spectra to the NIST database.</li>
	<li>Calculate the relative composition of starting materials and products by using Equation 2. 
	<img alt="Equation 2" src="/files/ftp_upload/65098/65098eq02v2.jpg" style="margin: auto;" />&#160; (Eq. 2) 
	where A is the chemical component of interest, and n is the number of components measured by GC-MS. An example is as follows: 
	<img alt="Equation 3" src="/files/ftp_upload/65098/65098eq3v2.jpg" style="margin: auto;" /></li>
</ol>

<ol>
	<li>Rytter, E., Hillestad, M., Austb&#248;, B., Lamb, J. J., Sarker, S., Lamb, J. J., Pollet, B. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+six+-+Thermochemical+production+of+fuels.">Chapter six - Thermochemical production of fuels.</a> Hydrogen, Biomass and Bioenergy. , 89-117 (2020).</li><li>Arpe, H. -. 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> Industrial Organic Chemistry. , (2017).</li><li>Orella, M. J., Rom&#225;n-Leshkov, Y., Brushett, F. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emerging+opportunities+for+electrochemical+processing+to+enable+sustainable+chemical+manufacturing.">Emerging opportunities for electrochemical processing to enable sustainable chemical manufacturing.</a> Current Opinion in Chemical Engineering. 20, 159-167 (2018).</li><li>May, A. S., Biddinger, E. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strategies+to+control+electrochemical+hydrogenation+and+hydrogenolysis+of+furfural+and+minimize+undesired+side+reactions.">Strategies to control electrochemical hydrogenation and hydrogenolysis of furfural and minimize undesired side reactions.</a> ACS Catalysis. 10 (5), 3212-3221 (2020).</li><li>Tang, B. Y., Bisbey, R. P., Lodaya, K. M., Toh, W. L., Surendranath, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reaction+environment+impacts+charge+transfer+but+not+chemical+reaction+steps+in+hydrogen+evolution+catalysis.">Reaction environment impacts charge transfer but not chemical reaction steps in hydrogen evolution catalysis.</a> ChemRxiv. , (2022).</li><li>Iwakura, C., Yoshida, Y., Inoue, H. <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+hydrogenation+system+of+4-methylstyrene+using+a+palladinized+palladium+sheet+electrode.">A new hydrogenation system of 4-methylstyrene using a palladinized palladium sheet electrode.</a> Journal of Electroanalytical Chemistry. 431 (1), 43-45 (1997).</li><li>Inoue, H., Abe, T., Iwakura, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Successive+hydrogenation+of+styrene+at+a+palladium+sheet+electrode+combined+with+electrochemical+supply+of+hydrogen.">Successive hydrogenation of styrene at a palladium sheet electrode combined with electrochemical supply of hydrogen.</a> Chemical Communications. , 55-56 (1996).</li><li>Conde, J. J., Maro&#241;o, M., S&#225;nchez-Herv&#225;s, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pd-based+membranes+for+hydrogen+separation:+Review+of+alloying+elements+and+their+influence+on+membrane+properties.">Pd-based membranes for hydrogen separation: Review of alloying elements and their influence on membrane properties.</a> Separation and Purification Reviews. 46 (2), 152-177 (2017).</li><li>Wicke, E., Brodowsky, H., Z&#252;chner, H., Alefeld, G., VÖlkl, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogen+in+palladium+and+palladium+alloys.">Hydrogen in palladium and palladium alloys.</a> Hydrogen in Metals II. Topics in Applied Physics., edited by Alefeld, G., V&#246;lkl, J. 29, (1978).</li><li>Sato, T., Sato, S., Itoh, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+a+hydrogen-permeable+palladium+membrane+electrode+to+produce+hydrogen+from+water+and+hydrogenate+toluene.">Using a hydrogen-permeable palladium membrane electrode to produce hydrogen from water and hydrogenate toluene.</a> International Journal Hydrogen Energy. 41 (12), 5419-5427 (2016).</li><li>Sherbo, R. S., Delima, R. S., Chiykowski, V. A., MacLeod, B. P., Berlinguette, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Complete+electron+economy+by+pairing+electrolysis+with+hydrogenation.">Complete electron economy by pairing electrolysis with hydrogenation.</a> Nature Catalysis. 1, 501-507 (2018).</li><li>Sherbo, R. S., Kurimoto, A., Brown, C. M., Berlinguette, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+electrocatalytic+hydrogenation+with+a+palladium+membrane+reactor.">Efficient electrocatalytic hydrogenation with a palladium membrane reactor.</a> Journal of American Chemical Society. 141 (19), 7815-7821 (2019).</li><li>Kurimoto, A., Sherbo, R. S., Cao, Y., Loo, N. W. X., Berlinguette, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrolytic+deuteration+of+unsaturated+bonds+without+using+D2.">Electrolytic deuteration of unsaturated bonds without using D2.</a> Nature Catalysis. 3, 719-726 (2020).</li><li>Jansonius, R. P., 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=Hydrogenation+without+H2+using+a+palladium+membrane+flow+cell.">Hydrogenation without H2 using a palladium membrane flow cell.</a> Cell Reports Physical Science. 1 (7), 100105 (2020).</li><li>Huang, 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=Electrolysis+can+be+used+to+resolve+hydrogenation+pathways+at+palladium+surfaces+in+a+membrane+reactor.">Electrolysis can be used to resolve hydrogenation pathways at palladium surfaces in a membrane reactor.</a> Journal of American Chemical Society Au. 1 (3), 336-343 (2021).</li><li>Delima, R. 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=Selective+hydrogenation+of+furfural+using+a+membrane+reactor.">Selective hydrogenation of furfural using a membrane reactor.</a> Energy and Environmental Science. 15 (1), 215-224 (2021).</li><li>Sato, T., Takada, A., Itoh, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-temperature+hydrogenation+of+toluene+by+electrolysis+of+water+with+hydrogen+permeable+palladium+membrane+electrode.">Low-temperature hydrogenation of toluene by electrolysis of water with hydrogen permeable palladium membrane electrode.</a> Chemistry Letters. 46 (4), 477-480 (2017).</li><li>Maoka, T., Enyo, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overpotential+decay+transients+and+the+reaction+mechanism+on+the+Pd-H2+electrode.">Overpotential decay transients and the reaction mechanism on the Pd-H2 electrode.</a> Surface Technology. 8 (5), 441-450 (1979).</li><li>Kurimoto, 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=Physical+separation+of+H2+activation+from+hydrogenation+chemistry+reveals+the+specific+role+of+secondary+metal+catalysts.">Physical separation of H2 activation from hydrogenation chemistry reveals the specific role of secondary metal catalysts.</a> Angewandte Chemie International Edition. 60 (21), 11937-11942 (2021).</li></ol>

Patent applications based on the technology described in this work have been filed and published: Berlinguette, C. P.; Sherbo, R. S. "Methods and Apparatus for Performing Chemical and Electrochemical Reactions" US Patent Application No. 16964944 (PCT filed January 2019, national entry July 2020), Publication No. US20210040017A1 (published February 2021). Canadian Patent Application No. 3089508 (PCT filed January 2019, national entry July 2020), Publication No. CA3089508 (published August 2019). Priority data: US Provisional Patent Application No. 62/622,305 (filed January 2018).

The Pd membrane enables hydrogen permeation and chemical hydrogenation. The preparation of this membrane is, therefore, important to the efficacy of the membrane reactor. The Pd membrane size, crystallography, and surface are tuned to improve the experimental results. Although Pd metal can evolve hydrogen at any thickness, the Pd membranes are rolled to 25 &#181;m. This standardization of membrane thickness ensures that the time it takes for hydrogen to permeate through the membrane is constant for all the experiments. M...

Thermochemical hydrogenation reactions are used in ~20% of all chemical synthesis1. These reactions require large quantities of H2 gas, which are usually derived from fossil fuels, temperatures between 150 &#176;C and 600 &#176;C, and pressures up to 200 atm2. Electrochemical hydrogenation is an appealing way to bypass these requirements and to drive hydrogenation reactions using water and renewable electricity3. For conventional electrochemical hydrogenation, an unsaturated feedstock is dissolved in a protic electrolyte in an electrochemical cell. When a potential is applied to the cell, water oxidation occurs at the anode, while hydrogenation occurs&#160;at the cathode. In this reaction setup, both electrochemical water oxidation and chemical hydrogenation occur in the same reaction environment. The organic substrate is dissolved in a protic electrolyte to enable both electrochemical water splitting and hydrogenation of the feedstock. The proximity of these reactions can lead to byproduct formation and electrode fouling when the reactant is susceptible to nucleophilic attack or if the reactant concentration is too high (&#62;0.25 M)4.
These challenges prompted our group to explore alternative ways to electrochemically drive hydrogenation reactions5,6,7. This search resulted in the use of a Pd membrane, which is conventionally used in hydrogen gas separation8. We use it as an electrode for water electrolysis on the electrochemical reactor side. This novel application of a palladium membrane enables the physical separation of the site of electrochemical water oxidation from the site of chemical hydrogenation. The resulting reactor configuration has two compartments: 1) an electrochemical compartment for hydrogen production; and 2) a chemical compartment for hydrogenation (Figure 1). Protons are generated in the electrochemical compartment by applying a potential across the Pt anode and the Pd membrane, which also serves as the cathode. These protons then migrate to the Pd membrane, where they are reduced to surface-adsorbed hydrogen atoms. The electrochemical compartment can be subdivided to include an optional cation exchange membrane to facilitate this proton migration. The surface-adsorbed hydrogen atoms permeate through the interstitial octahedral sites of the Pd fcc lattice9 and emerge on the opposite face of the membrane in the hydrogenation compartment, where they react with the unsaturated bonds of a given feedstock to form hydrogenated products7,10,11,12,13,14,15,16. The Pd in the membrane reactor, therefore, acts as (i) a hydrogen-selective membrane, (ii) a cathode, and (iii) a catalyst for hydrogenation.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/65098/65098fig1v2.jpg" /> 
Figure 1: Hydrogenation in a membrane reactor. Water oxidation at the anode produces protons, which are reduced on the palladium cathode. H permeates through the Pd membrane and reacts with propiophenone to form propylbenzene. Hydrogen evolution is a competing reaction that can occur on either side of the palladium membrane. For atmospheric mass-spectrometry, no chemical feedstock is used, necessitating H to leave the reactor in the form of H2 gas in either the electrochemical or hydrogenation compartments. <a href="https://www.jove.com/files/ftp_upload/65098/65098fig1largev2.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
The membrane reactor is assembled by sandwiching a Pd membrane between the anode and cathode compartments of an electrochemical H-cell12. Chemical-resistant O-rings are used to secure the membrane into place and ensure a leak-free seal. The electrochemical compartment of the membrane reactor contains a hydrogen-rich aqueous solution. In this study, we use 1 M H2SO4 and an anode that consists of a Pt wire enveloped in a 5 cm2 piece of platinum mesh. The anode is submerged in the electrolyte solution through a hole in the top of the electrochemical compartment. The chemical hydrogenation compartment contains a solvent and hydrogenation feedstock7,10,11,12,16,17. The hole at the top of the H-cell compartment is used for sampling. The experiments shown here use 0.01 M propiophenone in ethanol as the hydrogenation feed. However, the starting material (and concentration) can be varied to fit the experimental needs. For instance, a starting material that contains a long hydrocarbon chain and an alkyne functional group may be dissolved in pentane to improve solubility11. The applied current for the reaction can be between 5 mA/cm2 and 300 mA/cm2. All reactions are carried out under ambient temperature and pressure.
Atmospheric mass spectrometry (atm-MS) is used to measure the percent of hydrogen in the electrochemical compartment that permeates to the hydrogenation compartment11,12.&#160;This measurement is important to understand&#160;the energy inputs required for the membrane reactor, because it reveals the maximum possible hydrogen utilization (i.e., how much of the hydrogen being produced can actually be used for hydrogenation reactions). Hydrogen permeation through the Pd membrane is calculated by measuring the amount of H2 that evolves from both the electrochemical and hydrogenation compartments11,12. A permeation value of 100% means that all the hydrogen produced in the electrochemical compartment is transported through the Pd membrane to the hydrogenation compartment and then subsequently combines to form hydrogen gas. A permeation value of &#60;100% means&#160;that hydrogen evolution occurs in the electrochemical compartment prior to permeating through the membrane. As H2 is produced from either the electrochemical or hydrogenation compartment, it enters the instrument and is ionized to H2+. The quadrupole selects fragments of m/z = +2, and the corresponding charge is measured by the detector. The plot obtained by this technique is the ionic charge over time. The ionic charge is measured for the hydrogenation compartment first, and when the signal stabilizes, the channels are changed to measure the electrochemical compartment. Hydrogen permeation is calculated by dividing the average ionic charge in the hydrogenation compartment by the total ionic charge measured in the reactor (Equation 1)11,12. To calculate hydrogen permeation, H2 from the hydrogenation and electrochemical compartments are measured separately using atm-MS.
<img alt="Equation 1" src="/files/ftp_upload/65098/65098eq1v2.jpg" style="margin: auto;" /> (Eq. 1)
Gas chromatography mass spectrometry (GC-MS) is used to monitor the progress of the hydrogenation reaction12,14,15,16. To collect data for the example, the hydrogenation compartment of the reactor is filled with 0.01 M propiophenone in ethanol. By applying a potential across the Pt anode and the Pd cathode, reactive hydrogen is supplied to the hydrogenation compartment. The reactive hydrogen atoms then hydrogenate the unsaturated feedstock, and the products are quantified using GC-MS, where the sample is fragmented and ionized. By analyzing the mass of these fragments, the composition of the hydrogenation solution can be determined, and reaction rates can be calculated12,14,15,16.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Ag/AgCl Reference Electrode</td>
			<td>BASi research products</td>
			<td>MW-2021</td>
			<td>Reference electrode</td>
		</tr>
		<tr>
			<td>Analytical Balance</td>
			<td>Cole-Parmer</td>
			<td>RK-11219-03</td>
			<td>Instrument</td>
		</tr>
		<tr>
			<td>Atmospheric Mass Spectrometer</td>
			<td>ESS CatalySys</td>
			<td>NA</td>
			<td>Instrument</td>
		</tr>
		<tr>
			<td>Bench Power Supply</td>
			<td>Newark</td>
			<td>1550</td>
			<td>Instrument</td>
		</tr>
		<tr>
			<td>Conductive Copper Foil Electrical Tape&#160;</td>
			<td>McMaster Carr</td>
			<td>76555A711</td>
			<td>Electrochemical cell assembly</td>
		</tr>
		<tr>
			<td>Dichloromethane</td>
			<td>Sigma Aldrich</td>
			<td>270997</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Electric Rolling Press with Dual Micrometer</td>
			<td>MTI Corporation</td>
			<td>MR100A</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Electrochemical glass H-cell</td>
			<td>University of British Columbia glass blowing</td>
			<td>NA</td>
			<td>Electrochemical cell assembly</td>
		</tr>
		<tr>
			<td>ESS catalysis QUADSTAR</td>
			<td>ESS CatalySys</td>
			<td>NA</td>
			<td>Software</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Sigma Aldrich</td>
			<td>493511</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Flat Rolling Mill</td>
			<td>Pepetolls</td>
			<td>18700A</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Gas Chromatography Mass Spectrometer</td>
			<td>Agilent</td>
			<td>NA</td>
			<td>Instrument</td>
		</tr>
		<tr>
			<td>GC-MS vial</td>
			<td>Agilent</td>
			<td>5067-0205</td>
			<td>Vial for GC-MS</td>
		</tr>
		<tr>
			<td>Hexanes</td>
			<td>Sigma Aldrich</td>
			<td>1.0706</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Hydrochloric Acid</td>
			<td>Sigma Aldrich</td>
			<td>258148</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Hydrogen peroxide solution (30% v/v)</td>
			<td>Sigma Aldrich</td>
			<td>H1009</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Isopropyl Alcohol</td>
			<td>Sigma Aldrich</td>
			<td>W292907</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Masshunter Aquisition Software</td>
			<td>Agilent</td>
			<td>G1617FA</td>
			<td>Software</td>
		</tr>
		<tr>
			<td>Micropipette (100 &#181;L - 1000 &#181;L)</td>
			<td>Gilson</td>
			<td>F123602</td>
			<td>instrument</td>
		</tr>
		<tr>
			<td>Micropipette (20 &#181;L - 200 &#181;L)&#160;</td>
			<td>Gilson</td>
			<td>F123601</td>
			<td>Instrument</td>
		</tr>
		<tr>
			<td>Mitutoyo Digital Micrometer</td>
			<td>Uline</td>
			<td>H-2780</td>
			<td>Instrument</td>
		</tr>
		<tr>
			<td>Muffle Furnace</td>
			<td>MTI Corporation</td>
			<td>KSL-1100X</td>
			<td>Equipment</td>
		</tr>
		<tr>
			<td>Nitric acid</td>
			<td>Sigma Aldrich</td>
			<td>438073</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Nitrogen gas</td>
			<td>Sigma Aldrich</td>
			<td>608661</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Palladium (II) Chloride</td>
			<td>Sigma Aldrich</td>
			<td>520659</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Pd wafer bar, 1 oz, 99.95%</td>
			<td>Silver Gold Bull.</td>
			<td>NA</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Platinum Auxiliary Electrode</td>
			<td>BASi research products</td>
			<td>MW-1032</td>
			<td>Anode</td>
		</tr>
		<tr>
			<td>Potentiostat</td>
			<td>Metrohm</td>
			<td>PGSTAT302N</td>
			<td>Instrument</td>
		</tr>
		<tr>
			<td>Propiophenone</td>
			<td>Sigma Aldrich</td>
			<td>P51605</td>
			<td>Reagent</td>
		</tr>
		<tr>
			<td>Proton Exchange Membrane, Nafion 212</td>
			<td>Fuel cell store&#160;</td>
			<td>NA</td>
			<td>Electrochemical cell assembly</td>
		</tr>
		<tr>
			<td>Sulfuric acid&#160;</td>
			<td>Sigma Aldrich</td>
			<td>258105</td>
			<td>Reagent</td>
		</tr>
	</tbody>
</table>

hydrogen production and utilization in a membrane reactor

Industrial hydrogenation consumes ~11 Mt of fossil-derived H2 gas yearly. Our group invented a membrane reactor to bypass the need to use H2 gas for hydrogenation chemistry. The membrane reactor sources hydrogen from water and drives reactions using renewable electricity. In this reactor, a thin piece of Pd separates an electrochemical hydrogen production compartment from a chemical hydrogenation compartment. The Pd in the membrane reactor acts as (i) a hydrogen-selective membrane, (ii) a cathode, and (iii) a catalyst for hydrogenation. Herein, we report the use of atmospheric mass spectrometry (atm-MS) and gas chromatography mass spectrometry (GC-MS) to demonstrate that an applied electrochemical bias across a Pd membrane enables efficient hydrogenation without direct H2 input in a membrane reactor. With atm-MS, we measured a hydrogen permeation of 73%, which enabled the hydrogenation of propiophenone to propylbenzene with 100% selectivity, as measured by GC-MS. In contrast to conventional electrochemical hydrogenation, which is limited to low concentrations of starting material dissolved in a protic electrolyte, the physical separation of hydrogen production from utilization in the membrane reactor enables hydrogenation in any solvent or at any concentration. The use of high concentrations and a wide range of solvents is particularly important for reactor scalability and future commercialization.

Atm-MS is used to measure the ionic current of the hydrogen that is produced in the membrane reactor. We can use these measurements to quantify how much hydrogen permeates through the Pd membrane during electrolysis. First, the hydrogen evolving from the hydrogenation compartment is measured (Figure 3, left of the dotted lines). When the signal reaches a steady state, the channel is switched to the electrochemical compartment. The H2 gas evolving from the electrochemical compartme...

Watch this Scientific Journal Video about Hydrogen Production and Utilization in a Membrane Reactor at JoVE.com

Hydrogen Production and Utilization in a Membrane Reactor

Membrane reactors enable hydrogenation in ambient conditions without direct H2 input. We can track the hydrogen production and utilization in these systems using atmospheric mass spectrometry (atm-MS) and gas chromatography mass spectrometry (GC-MS).

Industrial hydrogenation consumes ~11 Mt of fossil-derived H2 gas yearly. Our group invented a membrane reactor to bypass the need to use H2 gas for ...

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Research

JoVE Journal

Chemistry

2.2K Views.  The University of British Columbia. Membrane reactors enable hydrogenation in ambient conditions without direct H2 input. We can track the hydrogen production and utilization in these systems using atmospheric mass spectrometry (atm-MS) and gas chromatography mass spectrometry (GC-MS).

Video: Hydrogen Production and Utilization in a Membrane Reactor

Analyzing Protein Dynamics Using Hydrogen Exchange Mass Spectrometry

All cellular processes depend on the functionality of proteins. Although the functionality of a given protein is the direct consequence of its unique amino acid sequence, it is only realized by the folding of the polypeptide chain into a single defined three-dimensional arrangement or more commonly into an ensemble of interconverting conformations. Investigating the connection between protein conformation and its function is therefore essential for a complete understanding of how proteins are able to fulfill their great variety of tasks. One possibility to study conformational changes a protein undergoes while progressing through its functional cycle is hydrogen-1H/2H-exchange in combination with high-resolution mass spectrometry (HX-MS). HX-MS is a versatile and robust method that adds a new dimension to structural information obtained by e.g. crystallography. It is used to study protein folding and unfolding, binding of small molecule ligands, protein-protein interactions, conformational changes linked to enzyme catalysis, and allostery. In addition, HX-MS is often used when the amount of protein is very limited or crystallization of the protein is not feasible. Here we provide a general protocol for studying protein dynamics with HX-MS and describe as an example how to reveal the interaction interface of two proteins in a complex. &#160;&#160;

Protein conformation and dynamics are key to understanding the relationship between protein structure and function. Hydrogen exchange coupled with high-resolution mass spectrometry is a versatile method to study the conformational dynamics of proteins as well as characterizing protein-ligand and protein-protein interactions, including contact interfaces and allosteric effects.

All cellular processes depend on the functionality of proteins. Although the functionality of a given protein is the direct consequence of its unique ...

Thin-layer Chromatographic (TLC) Separations and Bioassays of Plant Extracts to Identify Antimicrobial Compounds

A common screen for plant antimicrobial compounds consists of separating plant extracts by paper or thin-layer chromatography (PC or TLC), exposing the chromatograms to microbial suspensions (e.g. fungi or bacteria in broth or agar), allowing time for the microbes to grow in a humid environment, and visualizing zones with no microbial growth.&#160;The effectiveness of this screening method, known as bioautography, depends on both the quality of the chromatographic separation and the care taken with microbial culture conditions.&#160;This paper describes standard protocols for TLC and contact bioautography&#160;with a novel application to amino acid-fermenting bacteria. The extract is separated on flexible (aluminum-backed) silica TLC plates, and bands are visualized under ultraviolet (UV) light.&#160;Zones are cut out and incubated face down onto agar inoculated with the test microorganism.&#160;Inhibitory bands are visualized by staining the agar plates with tetrazolium red.&#160;The method is applied to the separation of red clover (Trifolium pratense cv. Kenland) phenolic compounds and their screening for activity against Clostridium sticklandii, a hyper ammonia-producing bacterium (HAB) that is native to the bovine rumen.&#160;The TLC methods apply to many types of plant extracts&#160;and other bacterial species (aerobic or anaerobic), as well as fungi, can be used as test organisms if culture conditions are modified to fit the growth requirements of the species.

Thin-layer Chromatographic TLC Separations and Bioassays of Plant Extracts to Identify Antimicrobial Compounds

Methods are described for thin-layer chromatographic (TLC) separation of plant extracts and contact bioautography to identify antibacterial metabolites. The methods are applied to the screening of red clover phenolic compounds inhibiting hyper&#160;ammonia-producing bacteria (HAB) native to the bovine rumen.

A common screen for plant antimicrobial compounds consists of separating plant extracts by paper or thin-layer chromatography (PC or TLC), exposing the ...

Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. Herein, nitrogen is presented as a novel supercritical drying fluid for specialized applications such as in the processing of reactive porous materials, where carbon dioxide and other fluids are not appropriate due to their higher chemical reactivity. Nitrogen exhibits similar physical properties in the near-critical region of its phase diagram as compared to carbon dioxide: a widely tunable density up to ~1 g ml-1, modest critical pressure (3.4 MPa), and small molecular diameter of ~3.6 &#197;. The key to achieving a high solvation power of nitrogen is to apply a processing temperature in the range of 80-150 K, where the density of nitrogen is an order of magnitude higher than at similar pressures near ambient temperature. The detailed solvation properties of nitrogen, and especially its selectivity, across a wide range of common target species of extraction still require further investigation. Herein we describe a protocol for the supercritical nitrogen processing of porous magnesium borohydride.

Nitrogen is an effective supercritical fluid for extraction or drying processes due to its small molecular size, high density in the near-liquid supercritical regime, and chemical inertness. We present a supercritical nitrogen drying protocol for the purification treatment of reactive, porous materials.

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. ...

A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions

There is a growing research interest in the development of portable systems which can deliver hydrogen on-demand to proton exchange membrane (PEM) hydrogen fuel cells. Researchers seeking to develop such systems require a method of measuring the generated hydrogen. Herein, we describe a simple, low-cost, and robust method to measure the hydrogen generated from the reaction of solids with aqueous solutions. The reactions are conducted in a conventional one-necked round-bottomed flask placed in a temperature controlled water bath. The hydrogen generated from the reaction in the flask is channeled through tubing into a water-filled inverted measuring cylinder. The water displaced from the measuring cylinder by the incoming gas is diverted into a beaker on a balance. The balance is connected to a computer, and the change in the mass reading of the balance over time is recorded using data collection and spreadsheet software programs. The data can then be approximately corrected for water vapor using the method described herein, and parameters such as the total hydrogen yield, the hydrogen generation rate, and the induction period can also be deduced. The size of the measuring cylinder and the resolution of the balance can be changed to adapt the setup to different hydrogen volumes and flow rates.

The study of methods to generate on-demand hydrogen for fuel cells continues to grow in importance. However, systems to measure hydrogen evolution from the reaction of chemicals with water can be complicated and expensive. This article details a simple, low-cost, and robust method to measure the evolution of hydrogen gas.

There is a growing research interest in the development of portable systems which can deliver hydrogen on-demand to proton exchange membrane (PEM) ...

Extraction of Ramie Fiber in Alkali Hydrogen Peroxide System Supported by Controlled-release Alkali Source

This protocol demonstrates a method for ramie fiber extraction by scouring raw ramie in an alkali hydrogen peroxide system supported by a controlled-release alkali source. The fiber extracted from ramie is a type of textile material of great importance. In previous studies, ramie fiber was extracted in an alkali hydrogen peroxide system supported only by sodium hydroxide.However, due to the strong alkalinity of sodium hydroxide, the oxidation reaction speed of hydrogen peroxide was difficult to control and thus resulted in great damage to the treated fiber. In this protocol, a controlled-release alkali source, which is composed of sodium hydroxide and magnesium hydroxide, is used to provide an alkali condition and buffer the pH value of the alkali hydrogen peroxidesystem. The substitution rate of magnesium hydroxide can adjust the pH value of the hydrogen peroxide system and has great influence on the fiber properties. The pH value and oxidation-reduction potential (ORP) value, which represents the oxidation ability of alkali hydrogen peroxide system, were monitored using a pH meter and ORP meter, respectively. The residual hydrogen peroxide content in the alkali hydrogen peroxide system during the extraction process and the chemical oxygen demand (COD) value of wastewater after fiber extraction are tested by KMnO4 titration method. The yield of fiber is measured using a precision electronic balance, and residual gums of fiber are tested by a chemical analysis method. The polymerization degree (PD value) of fiber is tested by an intrinsic viscosity method using the Ubbelohde viscometer. The tensile property of fiber, including tenacity, elongation, and rupture, is measured using a fiber strength instrument. Fourier transform infrared spectroscopy and X-ray diffraction are used to characterize the functional groups and crystal property of fiber. This protocol proves that the controlled-release alkali source can improve the properties of the fiber extracted in an alkali hydrogen peroxide system.

Presented here is a protocol for extraction of ramie fiber in alkali hydrogen peroxide system supported by controlled-release alkali source.

This protocol demonstrates a method for ramie fiber extraction by scouring raw ramie in an alkali hydrogen peroxide system supported by a ...

A Continuous-flow Photocatalytic Reactor for the Precisely Controlled Deposition of Metallic Nanoparticles

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic nanoparticles is developed. Guidelines for the replication of the reactor and its operation are provided in detail. Three different composite systems (Pt/graphene, Pt/TiO2, and Au/TiO2) with monodisperse and uniformly distributed particles are produced by this reactor, and the photodeposition mechanism, as well as the synthesis optimization strategy, are discussed. The synthesis methods and their technical aspects are described comprehensively. The role of the ultraviolet (UV) dose (in each excitation pulse) on the photodeposition process is investigated and the optimum values for each composite system are provided.

For a continuous and scalable synthesis of noble-metal-based nanocomposites, a novel photocatalytic reactor is developed and its structure, operation principles, and product quality optimization strategies are described.

In this work, a novel photocatalytic reactor for the pulsed and controlled excitation of the photocatalyst and the precise deposition of metallic ...

Reducing Willow Wood Fuel Emission by Low Temperature Microwave Assisted Hydrothermal Carbonization

Biomass is a sustainable fuel, as its CO2 emissions are reintegrated in biomass growth. However, the inorganic precursors in the biomass cause a negative environmental impact and slag formation. The selected short rotation coppice (SRC) willow wood has a high ash content (<img alt="Equation 1" src="/files/ftp_upload/58970/58970eq1.jpg" /> = 1.96%) and, therefore, a high content of emission and slag precursors. Therefore, the reduction of minerals from SRC willow wood by low temperature microwave assisted hydrothermal carbonization (MAHC) at 150 &#176;C, 170 &#176;C, and 185 &#176;C is investigated. An advantage of MAHC over conventional reactors is an even temperature conductance in the reaction medium, as microwaves penetrate the whole reactor volume. This allows a better temperature control and a faster cooldown. Therefore, a succession of depolymerization, transformation and repolymerization reactions can be analyzed effectively. In this study, the analysis of the mass loss, ash content and composition, heating values and molar O/C and H/C ratios of the treated and untreated SCR willow wood showed that the mineral content of the MAHC coal was reduced and the heating value increased. The process water showed a decreasing pH and contained furfural and 5-methylfurfural. A process temperature of 170 &#176;C showed the best combination of energy input and ash component reduction. The MAHC allows a better understanding of the hydrothermal carbonization process, while a large-scale industrial application is unlikely because of the high investment costs.

A protocol for the emission precursor depletion from low quality biomass by low temperature microwave assisted hydrothermal carbonization treatment is presented. This protocol includes the microwave parameters and the analysis of the biocoal product and process water.

Biomass is a sustainable fuel, as its CO2 emissions are reintegrated in biomass growth. However, the inorganic precursors in the biomass cause a negative ...

U2O5 Film Preparation via UO2 Deposition by Direct Current Sputtering and Successive Oxidation and Reduction with Atomic Oxygen and Atomic Hydrogen

We describe a method to produce U2O5 films in situ using the Labstation, a modular machine developed at JRC Karlsruhe. The Labstation, an essential part of the Properties of Actinides under Extreme Conditions laboratory (PAMEC), allows the preparation of films and studies of sample surfaces using surface analytical techniques such as X-ray and ultra-violet photoemission spectroscopy (XPS and UPS, respectively). All studies are made in situ, and the films, transferred under ultra-high vacuum from their preparation to an analyses chamber, are never in contact with the atmosphere. Initially, a film of UO2 is prepared by direct current (DC) sputter deposition on a gold (Au) foil then oxidized by atomic oxygen to produce a UO3 film. This latter is then reduced with atomic hydrogen to U2O5. Analyses are performed after each step involving oxidation and reduction, using high-resolution photoelectron spectroscopy to examine the oxidation state of uranium. Indeed, the oxidation and reduction times and corresponding temperature of the substrate during this process have severe effects on the resulting oxidation state of the uranium. Stopping the reduction of UO3 to U2O5 with single U(V) is quite challenging; first, uranium-oxygen systems exist in numerous intermediate phases. Second, differentiation of the oxidation states of uranium is mainly based on satellite peaks, whose intensity peaks are weak. Also, experimenters should be aware that X-ray spectroscopy (XPS) is a technique with an atomic sensitivity of 1% to 5%. Thus, it is important to obtain a complete picture of the uranium oxidation state with the entire spectra obtained on U4f, O1s, and the valence band (VB). Programs used in the Labstation include a linear transfer program developed by an outside company (see Table of Materials) as well as data acquisition and sputter source programs, both developed in-house.

U2O5 Film Preparation via UO2 Deposition by Direct Current Sputtering and Successive Oxidation and Reduction with Atomic Oxygen and Atomic Hydrogen

This protocol presents the preparation of U2O5 thin films obtained in situ under ultra-high vacuum. The process involves oxidation and reduction of UO2 films with atomic oxygen and atomic hydrogen, respectively.

We describe a method to produce U2O5 films in situ using the Labstation, a modular machine developed at JRC Karlsruhe. The Labstation, an essential part ...

Experimental Methods for Efficient Solar Hydrogen Production in Microgravity Environment

Long-term space flights and cis-lunar research platforms require a sustainable and light life-support hardware which can be reliably employed outside the Earth's atmosphere. So-called 'solar fuel' devices, currently developed for terrestrial applications in the quest for realizing a sustainable energy economy on Earth, provide promising alternative systems to existing air-revitalization units employed on the International Space Station (ISS) through photoelectrochemical water-splitting and hydrogen production. One obstacle for water (photo-) electrolysis in reduced gravity environments is the absence of buoyancy and the consequential, hindered gas bubble release from the electrode surface. This causes the formation of gas bubble froth layers in proximity to the electrode surface, leading to an increase in ohmic resistance and cell-efficiency loss due to reduced mass transfer of substrates and products to and from the electrode. Recently, we have demonstrated efficient solar hydrogen production in microgravity environment, using an integrated semiconductor-electrocatalyst system with p-type indium phosphide as the light-absorber and a rhodium electrocatalyst. By nanostructuring the electrocatalyst using shadow nanosphere lithography and thereby creating catalytic 'hot spots' on the photoelectrode surface, we could overcome gas bubble coalescence and mass transfer limitations and demonstrated efficient hydrogen production at high current densities in reduced gravitation. Here, the experimental details are described for the preparations of these nanostructured devices and further on, the procedure for their testing in microgravity environment, realized at the Bremen Drop Tower during 9.3 s of free fall.

Efficient solar-hydrogen production has recently been realized on functionalized semiconductor-electrocatalyst systems in a photoelectrochemical half-cell in microgravity environment at the Bremen Drop Tower. Here, we report the experimental procedures for manufacturing the semiconductor-electrocatalyst device, details of the experimental set-up in the drop capsule and the experimental sequence during free fall.

Long-term space flights and cis-lunar research platforms require a sustainable and light life-support hardware which can be reliably employed outside the ...

Solid Phase 11C-Methylation, Purification and Formulation for the Production of PET Tracers

Routine production of radiotracers used in positron emission tomography (PET) mostly relies on wet chemistry where the radioactive synthon reacts with a non-radioactive precursor in solution. This approach necessitates purification of the tracer by high performance liquid chromatography (HPLC) followed by reformulation in a biocompatible solvent for human administration. We recently developed a novel 11C-methylation approach for the highly efficient synthesis of carbon-11 labeled PET radiopharmaceuticals, taking advantage of solid phase cartridges as disposable &#34;3-in-1&#34; units for the synthesis, purification and reformulation of the tracers. This approach obviates the use of preparative HPLC and reduces the losses of the tracer in transfer lines and due to radioactive decay. Furthermore, the cartridge-based technique improves synthesis reliability, simplifies the automation process and facilitates compliance with the Good Manufacturing Practice (GMP) requirements. Here, we demonstrate this technique on the example of production of a PET tracer Pittsburgh compound B ([11C]PiB), a gold standard in vivo imaging agent for amyloid plaques in the human brains.

Solid Phase 11C-Methylation, Purification and Formulation for the Production of PET Tracers

We report an efficient carbon-11 radiolabeling technique to produce clinically relevant tracers for Positron Emission Tomography (PET) using solid phase extraction cartridges. 11C-methylating agent is passed through a cartridge preloaded with precursor and successive elution with aqueous ethanol provides chemically and radiochemically pure PET tracers in high radiochemical yields.

Routine production of radiotracers used in positron emission tomography (PET) mostly relies on wet chemistry where the radioactive synthon reacts with a ...