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

Abstract

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 (ΔG_L) 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 ΔG_L 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.