氮化碳作为一种新型聚合物半导体光催化剂，近几年来一直是太阳能转化材料与化学领域的研究热点之一。其中光还原转化二氧化碳有重要科研和实用价值。由于该反应涉及氮化碳与铂等金属团簇的表界面结构、光作用机理、表面反应过程等重要科学难题，一直是科研的巨大挑战。为了理清各类氮化碳的结构及对应的光催化性质并促进新催化剂的设计和发展，本项目将通过结合密度泛函理论计算方法和基于从头算的分子动力学模拟来研究氮化碳体系。并通过与实验课题组密切合作，重点构建缺陷melon，PTI，及PHI型氮化碳模型，并计算这几类氮化碳的电子结构和光催化性质；铂团簇负载在氮化碳表面的结构，寻找铂纳米颗粒的最优几何构型；通过对CO2光还原过程中关键步骤的化学物理本质和微观动力学研究，理解不同类型氮化碳/铂团簇表界面对关键基元步骤的影响；发展并优化针对氮化碳体系的高局域交换meta-GGA泛函。从而为氮化碳光催化剂的设计提供理论指导。

Photocatalysis on carbon nitride, a new type of metal-free photocatalyst, is a hot topic in the field of solar materials and chemistry, particularly in photocatalytic CO2 conversion. Because the process involves the complicated metal (Pt etc.) carbon nitride interface configurations, photocatalytic mechanisms, and the surface reactions, it is a challenging task to unravel the mechanism behind. In this project, we aim to build up computational models for three major types of carbon nitrides and study their corresponding electronic structure and photocatalytic properties via density functional theory calculations and ab initio molecular dynamics simulations. Through the close collaboration with the experimental groups, we first plan to construct the models of melon-based, PTI, and PHI carbon nitrides and then calculate their electronic structure and photocatalytic properties, which will be used to develop a specific high local exchange (HLE) meta-GGA density functional for the field of carbon nitride through tuning the factors of the exchange functional and the correlation functional of HLE17. The functional will then be used to study the size effect of platinum cocatalyst on surfaces of the melon-based, PTI, and PHI carbon nitrides as well as the CO2 photoreduction. Through the reaction pathway calculations and reaction dynamic simulations on key element steps of CO2 reductions, we wish to untangle the reaction mechanisms and dynamic properties of the selectivity and reactivity of the reactions as well as the roles of the Pt/carbon nitride interface. Overall, the simulation results aim to provide a molecular level understanding on the complicated processes of the CO2 photoreudction on carbon nitride for further development of the functional photocatalysts.