Computational design and screening of high-efficient metal dual-atom-modified g-C3N4 catalysts for CO2 photoreduction to C2 chemicals

This work investigated a series of metal dual-atom-modified g-C3N4 catalysts (CuM/g-C3N4, M = Mn, Fe, Co, Ni, Cu, Pd, In, Sn, Pt, and Bi) for the photoreduction of CO2 to C2 chemicals by density functional theory (DFT) calculations. It was found that CuPd/g-C3N4 has the best catalytic activity and selectivity for ethanol production, with *CO-*CO2 → *CO-*COOH as the energy-determining step which has a limiting free energy change (ΔGL) of 0.43 eV. CuSn/g-C3N4 has the best activity for ethylene generation, and the energy-determining step is *CHO-*CO → *CHOH-*CO, with a ΔGL of 0.68 eV. The adsorption free energies of key species such as *CO2 and *CO-*CO2 were identified as suitable descriptors to correlate the activity of CuM/g-C3N4 catalysts for CO2 reduction to ethanol. The activity of CO2 reduction to ethylene mainly depends on the desorption free energy of ethylene, and the CuSn/g-C3N4 catalyst was screened as a promising candidate for ethylene generation. This work reveals that the catalytic activity and product selectivity of CO2 photoreduction can be effectively regulated by carefully adjusting the composition of metal dual-atom active centers and their interactions with the g-C3N4 support, providing useful reference for future catalyst design.