Large amounts of CO₂ emissions associated with expanded fossil fuel consumption have caused global warming and energy crisis. The photocatalytic reduction of CO₂ is one of the most promising ways to solve these problems. However, some basic issues in CO₂ photocatalytic reduction over pure and modified TiO₂ surfaces, such as the transfer of photogenerated electrons, CO₂ adsorption configuration with excess electrons, the mechanism of CO₂ activation, still lack in-depth investigation and analysis. In this work, using density functional theory (DFT) calculations, we systematically calculated the transfer of photogenerated electrons, workfunction, CO₂ adsorption energy, charge density difference, density of states (DOS), and CO₂ dissociation energy barrier on different pure and metal single atom modified TiO₂ surfaces. Based on these results, we further analyzed the effect of photogenerated electrons and metal single atoms on CO₂ adsorption and activation, and identified the different behavior of photogenerated electrons on pure and metal single atom modified TiO₂ surfaces. Finally, a synergetic effect of photogenerated electrons and loaded metal atoms is proposed, which is crucial in understanding CO₂ photocatalytic reduction and designing efficient new photocatalytic materials.

与化石燃料消耗增加相关的大量CO ₂排放导致了全球变暖和能源危机。光催化还原CO ₂是解决这些问题最有前途的方法之一。然而，纯TiO 2 和改性TiO _{2表面CO 2}光催化还原的一些基本问题，如光生电子的转移、过量电子的CO _{2吸附构型、CO 2}活化机理等仍缺乏深入的研究和分析。在这项工作中，我们利用密度泛函理论（DFT）计算，系统地计算了光生电子的转移、功函数、CO ₂不同纯TiO 2 和金属单原子修饰的TiO ₂表面上的吸附能、电荷密度差、态密度(DOS)和CO ₂解离能垒。_{基于这些结果，我们进一步分析了光生电子和金属单原子对CO 2}吸附和活化的影响，并确定了光生电子在纯TiO 2 表面和金属单原子修饰的TiO ₂表面上的不同行为。最后，提出了光生电子和负载金属原子的协同效应，这对于理解CO ₂光催化还原和设计高效的新型光催化材料至关重要。