scholarly journals Stable, active CO2 reduction to formate via redox-modulated stabilization of active sites

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Le Li ◽  
Adnan Ozden ◽  
Shuyi Guo ◽  
F. Pelayo Garcı́a de Arquer ◽  
Chuanhao Wang ◽  
...  
Keyword(s):  
Active Sites ◽  
Structural Changes ◽  
Experimental Studies ◽  
Co2 Reduction ◽  
Membrane Electrode Assembly ◽  
Membrane Electrode ◽  
Faradaic Efficiency ◽  
Stable Production ◽  
Exchange Membrane

AbstractElectrochemical reduction of CO2 (CO2R) to formic acid upgrades waste CO2; however, up to now, chemical and structural changes to the electrocatalyst have often led to the deterioration of performance over time. Here, we find that alloying p-block elements with differing electronegativities modulates the redox potential of active sites and stabilizes them throughout extended CO2R operation. Active Sn-Bi/SnO2 surfaces formed in situ on homogeneously alloyed Bi0.1Sn crystals stabilize the CO2R-to-formate pathway over 2400 h (100 days) of continuous operation at a current density of 100 mA cm−2. This performance is accompanied by a Faradaic efficiency of 95% and an overpotential of ~ −0.65 V. Operating experimental studies as well as computational investigations show that the stabilized active sites offer near-optimal binding energy to the key formate intermediate *OCHO. Using a cation-exchange membrane electrode assembly device, we demonstrate the stable production of concentrated HCOO– solution (3.4 molar, 15 wt%) over 100 h.

Development and Application of a Sample Holder for In Situ Gaseous TEM Studies of Membrane Electrode Assemblies for Polymer Electrolyte Fuel Cells

2017 ◽  
Vol 23 (5) ◽  
pp. 945-950 ◽  
Author(s):  
Takeo Kamino ◽  
Toshie Yaguchi ◽  
Takahiro Shimizu
Keyword(s):  
Fuel Cells ◽  
Polymer Electrolyte ◽  
Structural Changes ◽  
Membrane Electrode Assembly ◽  
Polymer Electrolyte Fuel Cells ◽  
Polymer Electrolyte Fuel Cell ◽  
Membrane Electrode ◽  
Sample Holder ◽  
Electrode Assemblies

AbstractPolymer electrolyte fuel cells hold great potential for stationary and mobile applications due to high power density and low operating temperature. However, the structural changes during electrochemical reactions are not well understood. In this article, we detail the development of the sample holder equipped with gas injectors and electric conductors and its application to a membrane electrode assembly of a polymer electrolyte fuel cell. Hydrogen and oxygen gases were simultaneously sprayed on the surfaces of the anode and cathode catalysts of the membrane electrode assembly sample, respectively, and observation of the structural changes in the catalysts were simultaneously carried out along with measurement of the generated voltages.

scholarly journals Selective CO-to-acetate electroproduction via intermediate adsorption tuning on ordered Cu-Pd sites

2020 ◽  
Author(s):  
Yali Ji ◽  
Zheng Chen ◽  
Chao Yang ◽  
Yuhang Wang ◽  
Jie Xu ◽  
...  
Keyword(s):  
Active Sites ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Membrane Electrode Assembly ◽  
Membrane Electrode ◽  
Acetate Production ◽  
Faradaic Efficiency ◽  
Potential Alternative ◽  
Acetate Formation ◽  
Pure Cu

Abstract Electrochemical reduction of carbon monoxide (CO) has recently been emerging as a potential alternative for converting carbon emission into high-value multi-carbon products such as acetate. Nonetheless, the activity and selectivity for producing acetate have remained low. Herein, we developed an atomically ordered copper-palladium intermetallic compound (CuPd-IC) structure that achieved a high Faradaic efficiency of 70 ± 5% for CO-to-acetate production with a partial current density of 425 mA·cm− 2. This corresponded to an acetate production rate of 4.0 mmol·h− 1·cm− 2, and 5.3 times of enhancement in acetate production compared to pure Cu. Structural characterizations and density functional theory calculations suggested that CuPd-IC presents a high density of Cu-Pd pairs that act as the active sites to enrich the surface CO coverage, stabilize the surface ethenone as a key acetate-path intermediate, and inhibit hydrogen evolution reaction, thus promoting acetate formation. Using a membrane electrode assembly device, the CuPd-IC catalyst enabled 100 hours of CO-to-acetate operation at 500 mA·cm− 2 and an average acetate Faradaic efficiency of 43%, producing ~ 2 mol acetate.

scholarly journals Efficient CO2 electroreduction on facet-selective copper films with high conversion rate

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gong Zhang ◽  
Zhi-Jian Zhao ◽  
Dongfang Cheng ◽  
Huimin Li ◽  
Jia Yu ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Membrane Electrode Assembly ◽  
Membrane Electrode ◽  
Copper Films ◽  
Faradaic Efficiency ◽  
Polymer Binders ◽  
Co2 Electroreduction ◽  
High Conversion Rate ◽  
Insight Into

AbstractTuning the facet exposure of Cu could promote the multi-carbon (C2+) products formation in electrocatalytic CO2 reduction. Here we report the design and realization of a dynamic deposition-etch-bombardment method for Cu(100) facets control without using capping agents and polymer binders. The synthesized Cu(100)-rich films lead to a high Faradaic efficiency of 86.5% and a full-cell electricity conversion efficiency of 36.5% towards C2+ products in a flow cell. By further scaling up the electrode into a 25 cm2 membrane electrode assembly system, the overall current can ramp up to 12 A while achieving a single-pass yield of 13.2% for C2+ products. An insight into the influence of Cu facets exposure on intermediates is provided by in situ spectroscopic methods supported by theoretical calculations. The collected information will enable the precise design of CO2 reduction reactions to obtain desired products, a step towards future industrial CO2 refineries.

scholarly journals On the Effect of Anion Exchange Ionomer Binders in Bipolar Electrode Membrane Interface Water Electrolysis

2021 ◽  
Author(s):  
Britta Mayerhöfer ◽  
Konrad Ehelebe ◽  
Florian Dominik Speck ◽  
Markus Bierling ◽  
Johannes Bender ◽  
...  
Keyword(s):  
Proton Exchange Membrane ◽  
Water Electrolysis ◽  
Membrane Electrode Assembly ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Bipolar Electrode ◽  
Electrode Interface ◽  
Exchange Membrane ◽  
Electrode Membrane ◽  
Pem Water Electrolyzer

Bipolar membrane|electrode interface water electrolyzers (BPEMWE) were found to outperform a proton exchange membrane (PEM) water electrolyzer reference in a similar membrane electrode assembly (MEA) design based on individual porous...

Degradation study for membrane electrode assembly of anion exchange membrane fuel cell at a single-cell level

2021 ◽  
Author(s):  
Jonghyun Hyun ◽  
Seok-Hwan Yang ◽  
Gisu Doo ◽  
Sungyu Choi ◽  
Dong-Hyun Lee ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Single Cell ◽  
Anion Exchange ◽  
Membrane Electrode Assembly ◽  
Anion Exchange Membrane ◽  
Membrane Electrode ◽  
Single Cell Level ◽  
Cell Level ◽  
Degradation Study ◽  
Exchange Membrane

The durability of the membrane electrode assembly (MEA) is one of the important requirements for the successful commercialization of anion exchange membrane fuel cells (AEMFCs). While chemical stabilities of the...

scholarly journals MOF Derived Catalysts for Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cell

2018 ◽  
Vol 778 ◽  
pp. 275-282
Author(s):  
Noaman Khan ◽  
Saim Saher ◽  
Xuan Shi ◽  
Muhammad Noman ◽  
Mujahid Wasim Durani ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Membrane Electrode Assembly ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Nitrogen Doped ◽  
Nitrogen Doped Carbon ◽  
Exchange Membrane

Highly porous ZIF-67 (Zeolitic imidazole framework) has a conductive crystalline metal organic framework (MOF) structure which was served as a precursor and template for the preparation of nitrogen-doped carbon nanotubes (NCNTs) electrocatalysts. As a first step, the chloroplatinic acid, a platinum (Pt) precursor was infiltrated in ZIF-67 with a precise amount to obtain 0.12 mg.cm-2 Pt loading. Later, the infiltrated structure was calcined at 700°C in Ar:H2 (90:10 vol%) gas mixture. Multi-walled nitrogen-doped carbon nanotubes were grown on the surface of ZIF-67 crystals following thermal activation at 700°C. The resulting PtCo-NCNTs electrocatalysts were deposited on Nafion-212 solid electrolyte membrane by spray technique to study the oxygen reduction reaction (ORR) in the presence of H2/O2 gases in a temperature range of 50-70°C. The present study elucidates the performance of nitrogen-doped carbon nanotubes ORR electrocatalysts derived from ZIF-67 and the effects of membrane electrode assembly (MEA) steaming on the performance of proton exchange membrane fuel cell (PEMFC) employing PtCo-NCNTs as ORR electrocatalysts. We observed that the peak power density at 70°C was 450 mW/cm2 for steamed membrane electrode assembly (MEA) compared to 392 mW/cm2 for an identical MEA without steaming.

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