Stabilizing Cu2O for enhancing selectivity of CO2 electroreduction to C2H4 with the modification of Pd nanoparticles

Pd-Cu2O exhibits excellent performance in electrocatalytic CO2 reduction to C2H4, with an enhanced selectivity of 63.8% for over 35 h. The outstanding performance is attributed to the Pd modification which inhibits the reduction of the Cu+ in Cu2O and stabilizes the *CO intermediate during the CO2RR process. [Display omitted] •Utilizing the high work function Pd as an electron acceptor to stabilize Cu+.•Stabilization of *CO intermediates with Pd to facilitate CC coupling.•The Pd-Cu2O exhibits a high selectivity in CO2 converting to C2H4 of 63.8 %.•The Pd-Cu2O electrocatalyst demonstrates superior CO2 reduction stability. Electrocatalytic CO2 reduction reaction (CO2RR) to multi-carbon products (such as C2H4) provides an attractive approach to realize the closed-loop carbon economy. Although Cu2O has shown high C2H4 selectivity, it suffered from the low stability due to the easily reduced property of Cu+ during CO2RR. Herein, to stabilize Cu+ in Cu2O, Pd-Cu2O was designed and synthesized in this work. Owing to the high work function of Pd, electrons on Cu2O could be spontaneously transferred from Cu2O to Pd, thereby, stabilizing Cu+ in Cu2O by lowering the localized electron density. Furthermore, the presence of Pd can also enhance the stability of the *CO intermediate, which could subsequently enhance the CC coupling to generate C2H4 during CO2RR. The optimized catalyst exhibits high C2H4 Faradaic efficiency of 63.8% at −1.1 V vs. RHE, which is 1.5 times higher than that of pristine Cu2O. Additionally, the stability of Pd-Cu2O can be greatly improved, both the CO2 to C2H4 activity and selectivity can keep almost unchanged for over 35 h. This work provides an efficient strategy for stabilizing Cu+ and *CO intermediates to enhance C2H4 production efficiency.