Density Functional Theory Study of CO₂ Hydrogenation on Transition-Metal-Doped Cu(211) Surfaces

The massive emission of CO₂ has caused a series of environmental problems, including global warming, which exacerbates natural disasters and human health. Cu-based catalysts have shown great activity in the reduction of CO₂, but the mechanism of CO₂ activation remains ambiguous. In this work, we performed density functional theory (DFT) calculations to investigate the hydrogenation of CO₂ on Cu(211)-Rh, Cu(211)-Ni, Cu(211)-Co, and Cu(211)-Ru surfaces. The doping of Rh, Ni, Co, and Ru was found to enhance CO₂ hydrogenation to produce COOH. For CO₂ hydrogenation to produce HCOO, Ru plays a positive role in promoting CO dissociation, while Rh, Ni, and Co increase the barriers. These results indicate that Ru is the most effective additive for CO₂ reduction in Cu-based catalysts. In addition, the doping of Rh, Ni, Co, and Ru alters the electronic properties of Cu, and the activity of Cu-based catalysts was subsequently affected according to differential charge analysis. The analysis of Bader charge shows good predictions for CO₂ reduction over Cu-based catalysts. This study provides some fundamental aids for the rational design of efficient and stable CO₂-reducing agents to mitigate CO₂ emission.