Assessing Silver Palladium Alloys for Electrochemical CO2 Reduction in Membrane Electrode Assemblies. Issue 23 (2nd December 2021)

• Record Type: Journal Article
• Authors: Chandrashekar, Sanjana; Geerlings, Hans; Smith, Wilson A.
• Is Part Of: ChemElectroChem. Volume 8:Issue 23(2021)
• Page Start: 4515
• Page End: 4521
• Publication Date: 2021-12-02
• Subjects: membrane electrode assembly -- silver palladium alloys -- electrocatalysis -- catalytic activity -- spatial activity; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.202101258
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: The field of electrochemical CO2 reduction has been transitioning to industrially relevant scales by changing the architecture of the electrochemical cells and moving away from the traditional aqueous H‐cells to membrane electrode assemblies (MEA). The reaction environments in MEAs vary drastically from that of aqueous H‐cells, which could result in significantly different catalytic activity. In this paper, we test AgPd alloys, one of the most promising CO producing catalysts reported, at industrially relevant scales (50 to 200 mA/cm 2 ) in a MEA configuration. We report that, with increasing Pd composition in the electrode, the CO selectivity reduces from 99 % for pure Ag to 73 % for pure Pd at 50 mA/cm 2 . The MEA configuration helps attain a high CO partial current density of 123 mA/cm 2 . We find that catalytic activity reported in aqueous H‐Cells does not translate at higher current densities and that cell architecture must play an important role in benchmarking catalytic activity. Abstract : Highlighting the problem : A membrane electrode assembly (MEA) electrolyzer is used to study one of the most promising silver alloy catalysts for CO2 reduction, AgPd, at higher current densities than previously assessed. Compositionally variant thin films are deposited by magnetron sputtering onto GDEs and used as catalysts and tested at current densities up to 200 mA/cm 2 .The catalytic activity is found to be significantly different compared to activity reported in low current density configurations, showing the importance of screening catalysts at industrially relevant current densities and the need to bridge fundamental and applied studies of catalysts. CO selectivity is lost with increasing the Pd ratio, and is suspected to be due to the architecture of the MEA cell, emphasizing the need for catalyst design and testing at high current densities with various cell architectures.