The Impacts of Heterogeneous Constructing on the Low- and High-Index Facets of Cu2O on the Catalytic Performance and Reconstruction in Electrochemical CO2 Reduction Reaction

Abstract

Experimental and theoretical investigations demonstrate the intimate correlation between the catalytic performance of electrocatalysts and their crystal facets, with limited reports on the impact of high-index Cu2O facets on electrocatalytic CO2 reduction (ECO2RR). In this study, we synthesized a series of Cu2O microparticles exposing different crystal facets of (322), (111), (100) and Cu2O@Cu2S heterostructure catalysts with controlling surface sulfidation layer thickness through surface engineering and heterostructure strategies. Combined with experimental tests, theoretical calculations, and in-situ spectroscopic characterization techniques, we conducted a comprehensive analysis of the effects of crystal facets and heterostructures on Cu2O performance and stability. The results demonstrated that the conversion of *COOH to *CO is a spontaneous process on all crystal facets, despite the stronger CO2 adsorption and activation capabilities observed for low-index (111) and (100) facets. Notably, *CO desorption is facilitated on the (322) facet, demonstrating superior CO generation with a Faradaic efficiency of 85% at -0.62 V vs. RHE and excellent stability over 23 h. This work introduces a new avenue for enhancing the catalytic performance and stability of Cu2O electrocatalyst through crystal facet control and heterogeneous construction.