单原子催化材料的配位环境与协同效应对催化反应调控的理论研究

To improve the utilization efficiency of carbon resources and reduce CO2 emission is crucial for keeping sustainable development of human society and mitigating negative effects of climate change. One of the key solutions is to develop new catalysts. Recently, single-atom catalysts (SACs) were found to show high activity and selectivity for many reactions, for example, CO oxidation, nonoxidative conversion of methane etc. However, the underlying micro mechanism is still unclear. Using density functional theory calculations, we will investigate the effect of coordination environment and synergetic effect of SACs, such as Fe/M (M=ZnO、TiO2、CeO2、Al2O3) and N/TiO2 (N=Rh、Pd、Ir、Pt), on the reactivity and selectivity, using the methane coupling and reverse water-gas shift (RWGS) reaction as detective reactions. We will try to improve the selectivity of these two reactions, by tuning the energy barriers of several key competitive elementary reactions, such as CHx coupling and dehydrogenation, CO desorption and dissociation etc. The output of this proposal will establish the relationship between the structure of SACs and the reactivity and selectivity. It will provide theoretical guidelines for developing highly efficient SACs, used for selective conversion of methane and RWGS reaction. It will also provide theoretical insights into the tuning principle of reactivity and selectivity at the atomic level and establish the scientific basis/foundation for the directional design of SACs.

提高碳资源利用效率以及降低CO2排放是人类社会可持续发展以及应对环境气候变化所面临的迫切需求，解决这一问题的关键是催化新材料的开发。近期研究发现单原子材料(如：金属单原子嵌入氧化物晶格中)在很多催化反应比如CO氧化、甲烷无氧转化等反应中表现出极高的活性和选择性，但是对于其微观本质的认识尚不明确。本项目我们以甲烷直接偶联制乙烯和逆水气变换反应为探针，采用密度泛函理论计算方法，考察单原子催化材料Fe/M(M=ZnO、TiO2、CeO2和Al2O3）和N/TiO2(N=Rh、Pd、Ir和Pt)的配位环境(配位数、载体与金属间电荷转移等)和协同效应对一些关键中间体及基元反应如CHx偶联与脱氢，CO脱附与解离等的相对活性的调控，揭示单原子催化材料的结构与活性、选择性的构-效关系，从原子尺度理解单原子催化剂活性、选择性调变规律，为利用单原子催化新材料实现甲烷高效选择性转化和逆水气变换提供理论指导。

提高碳资源利用效率、降低CO2排放是人类社会可持续发展以及应对环境气候变化的迫切需求，解决这些问题的关键是催化新材料的开发。近期单原子材料在很多催化反应中表现出极高的活性和选择性，但是对于其微观机理的认识尚不明确。本项目以CH4直接偶联制乙烯、逆水汽变换和CO氧化反应为探针，采用密度泛函理论计算方法，研究了单原子催化材料M1/TiO2(M=3d V-Mn; 4d Nb、Mo、Ru-Pd和5d Ta-Pt等)的配位环境(配位数、金属与载体间电荷转移等)和协同效应对反应活性、选择性的影响，揭示了单原子材料的结构与性能之间的构-效关系，从原子尺度理解了单原子材料活性、选择性的调变规律，为优化CH4直接偶联制乙烯、逆水汽变换和CO氧化反应的催化剂设计提供了理论指导，推动了催化材料研发向着基于机理和结构导向的方向发展。项目资助期间，发表SCI论文3篇，包括2篇J. Phys. Chem. C论文和1篇Chem. Eng. J.论文，另有1篇论文在修改中，1篇论文在送审中，2篇论文在准备中。期间协助培养毕业硕士研究生3名。