无机超薄二维材料光电还原二氧化碳的同步辐射研究

Photoelectric catalytic reduction of CO2 to hydrocarbon fuels is one of the best solutions to solve the global warming and the energy shortage problems. In this project, we regard the ultrathin two-dimensional structure of transition metal oxides as the main research object, and study their photoelectric catalytic reduction of CO2. This project mainly concentrates on the large-scale synthesis, synchrotron radiation characterization and photoelectric catalytic properties of the ultrathin two-dimensional structures. Synchrotron radiation XANES, positron annihilation spectroscopy and theoretical calculations will be utilized to investigate the defect structure and electronic structure of the synthetic ultrathin two-dimensional materials. Ultrafast transient absorption spectroscopy will be applied to study the separation and transportation of the photoexcited carriers. Based on the effective strategies for fabricating ultrathin two-dimensional materials as well as the synchrotron radiation XANES, positron annihilation spectroscopy and first-principles calculations, an in-depth understanding of the correlations between synthesis, structure and property of the photoelectric CO2 reduction materials will be achieved, which hence provides a theoretical foundation and method guide to fabricate high-performance energy devices.

光电催化还原CO2成有机燃料小分子是解决能源短缺和全球变暖的有效途径之一。本项目拟以过渡金属氧化物的超薄二维结构为研究对象，聚焦其在光电催化还原CO2领域的应用。以超薄二维结构的宏量制备、同步辐射技术表征和光电催化性能的研究为关键科学问题，利用同步辐射XANES谱、正电子湮没谱和理论计算来研究其缺陷结构和电子结构，结合超快光谱和微观动力学行为研究电子与空穴的分离和传输，并测量其光电宏观特性和局域性能。在建立了系列过渡金属氧化物超薄二维结构制备方法的基础上，结合同步辐射XANES谱、正电子湮没谱和理论计算，将对高效光电还原CO2材料的合成-结构-性能三者之间的关系形成一些本质的理论认识，进而为组装构筑系列高性能能源器件提供一种理论基础和方法指导。

在该项目的实施中，项目负责人以过渡金属氧化物/硫属化合物的超薄二维片为研究对象，聚焦其在光/电还原CO2领域的应用，发展了过渡金属氧化物/硫属化合物超薄二维片的可控合成与宏量制备方法，利用同步辐射X射线吸收谱和正电子淹没谱揭示了其局域原子结构和缺陷结构，通过缺陷工程、合金化、异质结等策略实现对其电子结构的有效调控，结合理论模拟和原位红外光谱表征技术深入研究了基于原子级厚二维催化体系的光/电还原CO2性能，对高效光/电催化剂的合成-结构-性能三者之间的关系形成一些本质的理论认识，为新型高性能光/电还原CO2催化剂的设计和应用提供参考。以上工作超额完成项目任务书的研究内容，共在Nat. Energy、Nat. Commun.、J. Am. Chem. Soc.、Angew. Chem. Int. Ed.、Adv. Mater.等国际刊物上发表13篇学术论文。