用于CO2电还原的非贵金属（M-N-C）有序化膜电极构筑及其活性强化机制

非贵金属M-N-C催化剂取代贵金属（Au、Ag、Pd等）电催化CO2转化对减少CO2排放、实现碳中和具有重要的战略意义。针对M-N-C催化剂，优化电极结构以改善其传质性能对实现电解池在大电流条件下的高效运行至关重要。该项目拟聚焦M-N-C有序化膜电极，探索常温条件下在有序化载体纳米材料上负载高密度M-Nx活性位的新途径，以期实现M-N-C催化剂微纳结构有序化。采用电解池可视化等技术对气-液相传质阻力进行定性及定量研究，阐明膜电极及三相反应界面结构对传质特性的影响机制，进而指导膜电极结构设计与反应条件优化。针对M-N-C有序化膜电极稳定性，探究催化剂活性位及有序化载体结构的演变特性及其相互影响机制，从而解析膜电极失活的本质原因，探索提高M-N-C有序化膜电极稳定性的有效策略。项目率先展开用于CO2还原的非贵金属有序化膜电极研究，通过强化传质提高CO2还原电解池能量效率，促进其大规模产业化。

The electrochemical reduction of CO2 (eCO2RR) using renewable energy is an effective approach to reach global peaking of greenhouse gas emission as soon as possible and to pursue carbon neutrality. The eCO2RR to CO or syngas, with Au, Ag and Pd as the most efficient catalysts, is appealing due to its facile kinetics. Replacing the precious-group metals with non-precious group metal-based M-N-C catalysts has attracted extensive attention. However, the mass transportation of reactants and products is limited by the insufficient active site density and the narrow micro-pores as hosts for active sites, hindering their practical applications in CO2 electrolyzers with industrial current densities. Thus, it is of paramount importance to rationally design the structures of reactors and electrodes with abundant three-phase boundary interfaces. Herein, this project focuses on the 3D-ordered membrane electrode assembly (MEA) with M-N-C cathodes. Embedding M-Nx sites with high density into the 3D-ordered nano-supports at room temperature is the key to fabricate 3D-ordered M-N-C MEA. The qualitative and quantitative analysis of mass transport resistance in various 3D-ordered M-N-C MEAs will guide the optimization of MEA structures and the corresponding operation conditions. The interferences between structural change in active sites and morphological evolution of ordered nano-supports during operation will provide valuable insights on the basis of MEA degradation. This project pioneers in the rational design of 3D-ordered membrane electrode assembly (MEA) with non-precious metal based cathodes.