原位拉曼光谱研究Pd-Cu纳米催化剂电催化CO2还原构效关系及其反应机理

电催化二氧化碳还原（CO2RR）在储存可再生能源和缓解全球变暖方面具有光明的应用前景，Pd-Cu双金属催化剂由于在CO2RR表现出高活性和高选择性而备受人们关注，但其表界面电子结构究竟是如何影响反应物种的吸附和反应过程，目前缺乏直接实验证据。表面增强拉曼光谱（SERS）具有超高表面灵敏度、低波数区域检测等优势，能够反映分子水平上的结构信息，然而传统SERS难以适用实际纳米催化体系研究。本项目中，申请人拟利用壳层隔绝纳米粒子增强拉曼光谱（SHINERS），通过将纳米催化剂可控组装在具有强大拉曼增强能力的SHINs表面，从而将SHINERS应用到Pd-Cu催化剂上CO2电化还原过程原位研究，并精细调控催化剂的形貌与组成，在分子水平获取反应过程中金属-碳键、中间体等物种的演变规律，结合DFT计算推导反应机理并关联催化剂结构-中间物种-性能间的关系，为理性设计和改进CO2还原催化剂提供指导。

CO2 electrochemical reduction （CO2RR）shows great promise in storing renewable energy and alleviating global warming. Pd-Cu bimetallic catalyst with high activity and selectivity towards CO2RR has attracted a lot of attention. How does its electronic structure affect the intermediate adsorption and reaction process, currently only depends on theoretical speculation. Surface enhanced Raman spectroscopy (SERS) with non-destructive and extremely high surface sensitivity, could real-time detect the chemical reaction process at metal surface; however, it is difficult to be applied in nano-catalytic systems. In this project, we take shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) to investigate the electrocatalytic process of CO2RR at Pd-Cu nanocatalyst surfaces by assembling nanocatalyst on the SHINs. Furthermore, we controllably synthesize the catalysts with different structure and composition, and distinguish the differences between intermediate species at the molecular level. Combined with the DFT calculation, the reaction mechanism and the relationship among intermediate species, catalyst structure and catalytic performance are revealed, which could be useful for rationally designing high-performance catalysts.