Pd-Decorated Cu<sub>2</sub>O–Ag Catalyst Promoting CO<sub>2</sub> Electroreduction to C<sub>2</sub>H<sub>4</sub> by Optimizing CO Intermediate Adsorption and Hydrogenation
Xianbin Xu, Difei Xiao, Yugang Gao, Wenbo Li, Miaomiao Gao, Shuang Zhao, Zeyan Wang, Zhaoke Zheng, Peng Wang, Hefeng Cheng, Yuanyuan Liu, Ying Dai, Baibiao Huang
Abstract
Electrocatalytic CO 2 reduction reaction (CO 2 RR) to high value-added products, such as ethylene (C 2 H 4 ), 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 C 2 H 4 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 H 2 O activation ability hinders the hydrogenation of intermediates. To break through the above bottleneck, herein, palladium (Pd) was introduced into Cu 2 O–Ag, a typical conventional tandem catalyst, to construct a Cu 2 O–Pd–Ag ternary catalyst. Extensive experiment and density functional theory calculation prove that Pd can efficiently stabilize the *CO intermediate and promote the H 2 O activation, which contributes to the C–C coupling and intermediate hydrogenation, the key steps in the conversion of CO 2 to C 2 H 4 . Beneficial to the efficient synergy of Cu 2 O, Pd, and Ag, the optimal Cu 2 O–Pd–Ag ternary catalyst achieves CO 2 RR toward C 2 H 4 with a faradaic efficiency of 63.2% at −1.2 V RHE, which is higher than that achieved by Cu 2 O–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 CO 2 RR electrocatalyst.