Synergistic Cr2O3@Ag Heterostructure Enhanced Electrocatalytic CO2 Reduction to CO

Abstract The electrocatalytic CO 2 RR to produce value‐added chemicals and fuels has been recognized as a promising means to reduce the reliance on fossil resources; it is, however, hindered due to the lack of high‐performance electrocatalysts. The effectiveness of sculpturing metal/metal oxides (MMO) heterostructures to enhance electrocatalytic performance toward CO 2 RR has been well documented, nonetheless, the precise synergistic mechanism of MMO remains elusive. Herein, an in operando electrochemically synthesized Cr 2 O 3 –Ag heterostructure electrocatalyst (Cr 2 O 3 @Ag) is reported for efficient electrocatalytic reduction of CO 2 to CO. The obtained Cr 2 O 3 @Ag can readily achieve a superb FE CO of 99.6% at −0.8 V (vs RHE) with a high J CO of 19.0 mA cm −2 . These studies also confirm that the operando synthesized Cr 2 O 3 @Ag possesses high operational stability. Notably, operando Raman spectroscopy studies reveal that the markedly enhanced performance is attributable to the synergistic Cr 2 O 3 –Ag heterostructure induced stabilization of CO 2 •− /*COOH intermediates. DFT calculations unveil that the metallic‐Ag‐catalyzed CO 2 reduction to CO requires a 1.45 eV energy input to proceed, which is 0.93 eV higher than that of the MMO‐structured Cr 2 O 3 @Ag. The exemplified approaches in this work would be adoptable for design and development of high‐performance electrocatalysts for other important reactions.