二氧化碳（CO2）电化学还原生成甲烷等小分子有机化合物对解决人类当前所面临的环境和能源问题至关重要。Cu 是过渡金属中实现这一转换较为优异的催化剂之一。目前关于Cu电极表面CO2电化学还原精确的反应机理仍然没有确定，这对反应的调控及催化剂的设计极为不利。本项目拟采用第一性原理，使用密度泛函理论（DFT）方法进行结构优化、反应自由能计算和最小能量路径分析，研究CO2在Cu各种单晶电极表面的化学还原和电化学还原过程，计算不同电极电势下CO2电化学还原各步骤的反应自由能和活化能，从而揭示CO2在Cu单晶电极表面形成碳氢化合物可能的最佳反应路径及反应的难易程度，以实现对CO2还原机理的系统理解。在此基础上，研究合金化对CO2电化学还原路径的影响。项目的研究成果对于深入认识整个CO2电化学还原过程的选择性、表面结构敏感性及催化剂尺寸效应等具有重要意义，为相关催化剂的设计提供科学依据。

Carbon dioxide (CO2) electrochemical reduction to form small molecule organic compound such as methane is extremely important for solving the environmental and energy issues that humanity facing. Cu is one of the comparatively excellent catalysts for achieving this conversion in the transition metals. Currently, the precise reaction mechanism is still not been determined, which is extremely unfavorable for control of the reaction and design of the catalysts. Therefore, CO2 chemical and electrochemical reduction processes on the Cu single crystal surfaces will be studied using density functional theory (DFT) method in the first principle on the geometry structural optimization, the reaction free energies calculations and the minimum energy paths analysis, and the reaction free energies and the activation barriers of each CO2 electrochemical reduction step will be calculated under different electrode potential. Accordingly, the possible optimized reaction paths of CO2 reduction to form hydrocarbons on the Cu single crystal electrode surfaces and degree of difficulty of the reaction can be revealed, and systematical understanding of CO2 reduction mechanism can be achieved. On this basis, the effect of alloying on CO2 electrochemical reduction paths is studied. The research results of the project have great significance for understanding in depth the selectivity of CO2 electrochemical reduction process, the sensitivity of surface structure and size effect of catalysts. Simultaneously, the research results can provide a scientific basis for designing the catalysts of CO2 electrochemical reduction.