Electrochemical CO₂ reduction has become a promising technology to address the globally accelerating CO₂ emissions and produce value-add chemicals and liquid fuels. In this work, transition metals supported on graphitic carbon nitride (M/g-C₃N₄, M = Fe, Co, Ni) as catalysts applied in electrochemical CO₂ reduction to CH₃OH and CH₄ is investigated by density functional theory (DFT) calculations. From Ni/g-C₃N₄, Fe/g-C₃N₄ to Co/g-C₃N₄, the interaction between CO₂ and catalysts is found to be gradually enhanced, especially for the adsorption of CO₂ on Co/g-C₃N₄, which is a typical chemical interaction. Fe/g-C₃N₄ and Co/g-C₃N₄ prefer to produce CH₄ with limiting potentials of 0.67 V and 0.81 V, while Ni/g-C₃N₄ tends to produce CH₃OH. Moreover, the electrolyte environment has little influence on the limiting potential of Fe/g-C₃N₄ and Ni/g-C₃N₄. Given the superior performance of M/g-C₃N₄, g-C₃N₄ shows great potential as the platform to support transition metal for CO₂ reduction system. These insights can be used to guide the synthesis of highly active CO₂ reduction catalysts from nonprecious metals.

电化学减少CO ₂已经成为解决全球加速的CO ₂排放并生产增值化学品和液体燃料的有前途的技术。在这项工作中，通过密度泛函理论（DFT）研究了负载在石墨氮化碳上的过渡金属（M / gC ₃ N ₄，M = Fe，Co，Ni）作为电化学CO ₂还原成CH ₃ OH和CH _4的催化剂）计算。从Ni / gC ₃ N ₄，Fe / gC ₃ N ₄到Co / gC ₃ N ₄，CO ₂之间的相互作用并且发现催化剂逐渐增强，特别是对于CO ₂在Co / gC ₃ N ₄上的吸附，这是典型的化学相互作用。Fe / gC ₃ N ₄和Co / gC ₃ N ₄倾向于产生极限电位为0.67 V和0.81 V的CH ₄，而Ni / gC ₃ N ₄倾向于产生CH ₃ OH。此外，电解质环境对Fe / gC ₃ N ₄和Ni / gC ₃ N ₄的极限电位几乎没有影响。鉴于M / gC ₃ N的卓越性能_如图4所示，gC ₃ N ₄作为支撑过渡金属用于CO ₂还原系统的平台显示出巨大的潜力。这些见解可用于指导由非贵金属合成高活性CO ₂还原催化剂。