The Effect of Catholyte and Catalyst Layer Binders on CO2 Electroreduction Selectivity

Electrochemical reduction of carbon dioxide (CO₂) is an attractive technology for converting CO₂ to value-added chemicals by using renewably generated electricity. This work combines both experimental and theoretical analyses to investigate the role of different catalysts (Ag/Vu and SnO₂/Vu), binder materials, and catholyte compositions on the selectivity of a CO₂ electrolysis cell to the two-electron CO₂ reduction products CO and formate. As a complementary effort, a 2D multi-physics transport model was developed to elucidate the fundamental processes and species concentrations in the cathode components. It was shown that the selectivity of CO₂ reduction to CO can change significantly when different catholyte compositions and binder materials are used, whereas the selectivity of CO₂ to formate is relatively stable across the conditions studied. These insights can be used to inform decisions regarding the electrode development and system design in CO₂ electrolyzers and ultimately contribute to scaling energy-efficient electrochemical CO₂-reduction systems.