金属间化合物-金属氧化物异质结构纳米晶的可控合成及其在高效二氧化碳加氢反应中的应用

The excessive consumption of fossil fuels has caused a worldwide energy crisis, and the CO2 and other greenhouse gases produced by it have brought serious environmental problems. By means of chemical fixation, the hydrogenation of CO2 into high value-added chemicals and fuels is considered as the best way to solve this problem. As CO2 molecules are extremely stable, catalysts are needed to reduce the activation energy of CO2. Therefore, it is the key to seek high-activity and high-selectivity catalysts through reasonable design. In this project, heterostructure nanocrystals of CuM-MO (M=In, Sn, Zn) were selected as the research object, focusing on the phase change of CuM intermetallic compounds and the effect of the CuM center and MO metal oxidation interface on the catalytic activity (current density) of CO2 and the selectivity of products (Faraday current efficiency). Furthermore by means of FTIR, X-ray absorption fine structure spectroscopy (XAFS), ultrahigh resolution accurate in-situ XPS characterization methods, combined with the first principles calculation, from the molecular level atoms in different phase of the study of CO2 stripping absorption on the surface of the catalyst, the chemical bond rupture, and combination, the electron transfer process, clear interface and catalytic performance of the catalyst phase and table structure-activity relationship. The successful implementation of this project will lay a solid foundation for obtaining a commercially available high-efficiency CO2 catalytic conversion catalyst.

石化燃料过度消耗引起了世界范围内的能源危机，产生的CO2等温室气体带来了严重的环境问题。通过化学固定的手段，将 CO2加氢合成高附加值化学品及燃料被认为是解决该问题的最佳途径。由于 CO2分子极其稳定，需要催化剂来降低 CO2转化的活化能，通过合理的设计寻求高活性和高选择性的催化剂是关键所在。本项目选择CuM-MO(M=In, Sn, Zn)异质结构纳米晶为研究对象，重点研究CuM金属间化合物物相变化以及CuM中心与MO金属氧化界面对CO2的催化活性、产物的选择性的影响。此外借助于FTIR、X射线吸收精细结构谱（XAFS）、超高分辨准原位XPS等表征手段，结合第一性原理计算，从原子分子层面上研究CO2在不同物相的催化剂表面的吸脱附、化学键的断裂和结合、电子的转移过程，明确催化剂物相以及表界面与催化性能的构效关系。与本项目的成功实施，为获得商业化可用的高效CO2催化转化催化剂奠定坚实的基础。

Cu/Zn催化剂是CO2加氢催化剂反应中应用最广泛的催化剂，但是对于该类催化剂在反应中真实催化位点的探究，一直是研究的热点和难点。本项目成功构建Cu-Zn/ZnO结构，并通过原位红外、原位XPS等手段，对催化过程中催化剂的价态、反应过程中催化反应中间体的类型等进行了详细的探究，明确了催化剂在反应中的重构过程。并通过理论建模和计算，计算反应路径，明确反应机理，加深了对CO2加氢反应机理的认识，为后续指导CO2加氢催化剂的设计合成提供了方向。