Effect of crystal defects on the selectivity of a bulk Cu–Zn alloy for electrocatalytic CO2 reduction

Abstract

The elemental composition and crystal structure of catalysts are important factors affecting the product selectivity in the electrochemical CO₂ reduction reaction (CO₂RR). It remains challenging to tune the product selectivity by precisely regulating crystal defects such as grain boundaries and dislocations in the catalysts. In this study, the crystal defects (including grain boundaries and dislocations) of the bulk CuZn alloy were quantitatively regulated on a microscopic scale through severe plastic deformation by using the high-pressure torsion (HPT) technique combined with annealing treatments, and the effect of crystal defects on electrocatalytic CO₂RR performances was systematically studied. The results show that abundant grain boundaries and dislocations can promote the formation of CH₄ and C₂H₄, while inhibiting the formation of CO. Moreover, a high dislocation density will impede the rapid transfer of charges and suppress the formation of C₂H₅OH. This study highlights the potential of defect engineering in designing catalysts to improve the selectivity for desired CO₂RR products.