电催化CO2还原的原位谱学研究进展

Research Progress of Operando Spectroscopy for Electrocatalytic CO2 Reduction

摘要:

可再生电力驱动的电催化二氧化碳还原反应（CO₂RR）能将CO₂转化为具有经济价值的燃料和化学品，是实现“碳闭环”，达成“碳达峰”和“碳中和”的关键技术。CO₂RR产物之一的甲酸(HCOOH)经济附加值是重要评价因素，以低耗能、高价值而获得学术和产业界的广泛关注。由于p区金属(如锡、铋、铟、和铅)能以高法拉第效率催化CO₂RR而产生HCOOH，因此探究其催化机理和反应活性位点，能够为研发实用型催化剂和优化反应环境提供重要基础支撑。总结了原位观测技术在研究p区金属催化CO₂RR机理和活性位点中的应用，常用的原位观测技术包括拉曼光谱、红外吸收光谱、X射线吸收谱和差分电化学质谱，借助原位观测技术不仅可以分析催化剂表面的化学成键、分子结构、结晶度等信息，还能在电位动态扫描过程中以毫秒的时间分辨对电化学反应产生的气态或易挥发产物，从而进行定性或定量分析。通过原位观测或工况条件下获取的实验数据确认CO₂RR的催化成分，构建反应路径图，为进一步设计高性能、高稳定性的催化剂提供了必要条件。此外，合金化是改良催化剂性能的主要策略之一，简要讨论了p区金属合金化对电子结构、表面性质、催化效果的影响。通过总结原位观测技术对在p区金属催化研究的重要作用，为CO₂RR工程化发展提供坚实基础和创新思路。

Abstract:

Electrocatalytic CO₂ reduction reaction （CO₂RR） driven by renewable electricity is able to convert CO₂ to valuable fuels or chemicals， so that it is considered to be a key technique to close the carbon cycle， and to achieve the goals of carbon neutrality. The techno-economic analysis suggests that the production of formic acid （HCOOH） via CO₂RR could generate higher value while consuming less energy. Thus， the CO₂RR to HCOOH has received extensive attention from academia and industry. P-block metals， such as Sn， Bi， In， and Pb， can be used as electrocatalysts for CO₂RR to HCOOH with a high Faradaic efficiency. The understanding of reaction mechanisms and active sites facilitates the development of practicable electrocatalysts and the optimization of the reaction environment. This work summarizes the operando techniques， which have been used to investigating the CO₂RR on p-block metals. The operando techniques include Raman spectroscopy， infrared absorption spectroscopy， X-ray absorption spectroscopy， and differential electrochemical mass spectroscopy. Utilizing in-situ observation technology， we can not only analyze fingerprint information such as chemical bonding， molecular structure， and crystallinity on the catalyst surface， but also conduct qualitative or quantitative analysis of gaseous or volatile products resulting from electrochemical reactions with millisecond time resolution during the potential dynamic scanning process. Through the experimental data obtained under in-situ conditions， the catalytic components of CO₂RR were identified， and the reaction pathway diagram was constructed， laying the groundwork for the further design of high-performance and high-stability catalysts. Additionally， alloying is one of the main strategies to improve the performance of catalysts. In this paper， the effects of p-block metal alloying on electronic structure， surface properties and catalytic effect are briefly discussed. This review emphasizes the importance of operando spectroscopic technology in the research of p-block metal catalysts， and provides a solid foundation and innovative ideas for the engineering development of CO₂RR.