Electrochemical CO2 reduction reaction (CO2RR) with renewable electricity is a potentially sustainable method to reduce CO2 emissions. Palladium supported on cost‐effective transition‐metal carbides (TMCs) are studied to reduce the Pd usage and tune the activity and selectivity of the CO2RR to produce synthesis gas, using a combined approach of studying thin films and practical powder catalysts, in situ characterization, and density functional theory (DFT) calculations. Notably, Pd/TaC exhibits higher CO2RR activity, stability and CO Faradaic efficiency than those of commercial Pd/C while significantly reducing the Pd loading. In situ measurements confirm the transformation of Pd into hydride (PdH) under the CO2RR environment. DFT calculations reveal that the TMC substrates modify the binding energies of key intermediates on supported PdH. This work suggests the prospect of using TMCs as low‐cost and stable substrates to support and modify Pd for enhanced CO2RR activity.

Electrochemical CO2 reduction reaction (CO2RR) is one of the promising strategies for converting CO2 to value‐added chemicals. Gold (Au) catalysts are considered to be the best benchmarking materials for CO2RR to produce CO. In this work, the role of different functional groups of polymeric binders on CO2RR over Au catalysts is systematically investigated by combined experimental measurements and density functional theory (DFT) calculations. Especially, it is revealed that the functional groups can play a role in suppressing the undesired hydrogen evolution reaction, the main competing reaction against CO2RR, thus enabling more catalytic active sites to be available for CO2RR and enhancing the CO2RR activity. Consistent with the DFT prediction, fluorine (F)‐containing functional groups in the F‐rich polytetrafluoroethylene binder lead to a high Faradaic efficiency (≈94.7%) of CO production. This study suggests a new strategy by optimizing polymeric binders for the selective CO2RR.