Scheme 1. Cascade Reaction Mechanism on a Ag–Cu Nanozyme for CO₂RR.

In the nanozyme, we propose the CO₂RR is following the cascade reaction mechanism: (i) diffusion of CO₂ through the porous Cu shell to the Ag core, (ii) adsorption of CO₂ on the Ag surface, (iii) proton-coupled reduction of CO₂ to CO, (iv) desorption of CO and diffusion through the porous Cu shell, (v) adsorption of CO on the Cu channel walls, (vi) proton-coupled bimolecular reduction of multiple CO molecules to C_≥2 products, and (vii) desorption and diffusion of C_≥2 products to the bulk of the solution.