CO₂ conversion to valuable products on ZnO (0001) monolayer doped by transition metals (TM-ZnO where TM is Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) was investigated by density functional theory calculation. The results show that doping TMs can reduce the overpotential for CO₂ reduction reaction (CRR) compared to pristine ZnO. Significantly, the oxidation state of TMs by different d-orbital occupancy results in a change of the electronic properties of the catalysts, leading to a difference in reactivity, reaction pathway, and selectivity of the final products. Early TMs (Sc to Cr) showing oxidation state 3⁺ prefer CH₄ as a product while late TMs (Mn to Cu) showing oxidation state 2⁺ can make HCOOH. Remarkably, Co-ZnO can produce HCOOH with ultra-low overpotential at 0.02 V and can further produce CH₃OH with an overpotential of only 0.45 V. Therefore, Co-ZnO monolayer is suggested as a promising CRR catalyst for experimental research. This work sheds light on the rational design of low-cost metal oxides with high stability, activity, and product selectivity for CRR and other reactions.

通过密度泛函理论计算研究了在过渡金属（TM-ZnO，其中TM为Sc，Ti，V，Cr，Mn，Fe，Co，Ni和Cu）掺杂的ZnO（0001）单层上将CO ₂转化为有价值的产品的过程。结果表明，与原始ZnO相比，掺杂TM可以减少CO ₂还原反应（CRR）的过电位。值得注意的是，TMs被不同的d轨道占有率所氧化的状态导致了催化剂电子性质的改变，从而导致了反应性，反应途径和最终产物选择性的差异。表现出氧化态3 ^+的早期TM（Sc至Cr）更喜欢CH ₄作为产物，而表现出氧化态2 ^+的晚期TMs（Mn至Cu）可以制作HCOOH。值得注意的是，Co-ZnO可以在0.02 V时产生超低超电势的HCOOH，并且还可以进一步产生仅0.45 V的超电势的CH ₃ OH。因此，建议将Co-ZnO单层作为有希望的CRR催化剂用于实验研究。这项工作为合理设计低成本金属氧化物提供了高稳定性，活性和对CRR和其他反应的产物选择性。