Pd-Decorated Cu₂O-Ag Catalyst Promoting CO₂ Electroreduction to C₂H₄ by Optimizing CO Intermediate Adsorption and...

Electrocatalytic CO₂ reduction reaction (CO₂RR) to high value-added products, such as ethylene (C₂H₄), offers a promising approach to achieve carbon neutrality. Although recent studies have reported that a tandem catalyst (for example, Cu-Ag systems) exhibits advantage in C₂H₄ production, its practical application is largely inhibited by the following: (1) a traditional tandem catalyst cannot effectively stabilize the *CO intermediate, resulting in sluggish C-C coupling, and (2) inadequate H₂O activation ability hinders the hydrogenation of intermediates. To break through the above bottleneck, herein, palladium (Pd) was introduced into Cu₂O-Ag, a typical conventional tandem catalyst, to construct a Cu₂O-Pd-Ag ternary catalyst. Extensive experiment and density functional theory calculation prove that Pd can efficiently stabilize the *CO intermediate and promote the H₂O activation, which contributes to the C-C coupling and intermediate hydrogenation, the key steps in the conversion of CO₂ to C₂H₄. Beneficial to the efficient synergy of Cu₂O, Pd, and Ag, the optimal Cu₂O-Pd-Ag ternary catalyst achieves CO₂RR toward C₂H₄ with a faradaic efficiency of 63.2% at -1.2 V_RHE, which is higher than that achieved by Cu₂O-Ag and most of other reported catalysts. This work is a fruitful exploration of a rare ternary catalyst, providing a new route for constructing an efficient CO₂RR electrocatalyst.