Yang Huijuan, Wu Rongliang, Li Wei, Wen Jin
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
Phys Chem Chem Phys. 2024 May 15;26(19):14205-14215. doi: 10.1039/d4cp01085j.
Graphitic carbon nitride (g-CN or GCN) shows promise in photocatalytic water splitting, despite facing the challenge of rapid electron-hole recombination. In this study, we investigated the influence of boron/oxygen codoping on the photocatalytic performance of GCN systems for hydrogen generation. First-principles calculations and nonadiabatic molecular dynamics (NAMD) simulations were employed to reveal that the recombination time of photogenerated carriers could be increased by 16% to 64% in the codoped systems compared to the pristine GCN. The time-dependent density functional theory (TDDFT) scheme was utilized to select energy windows and initiate dynamics in cluster models of B/O co-doped heptazine with water molecules. Notably, we observed efficient direct photodissociation of hydrogen atoms from water molecules within 60 fs and proton hops within the hydrogen-bonded network within 80 fs in the co-doped system, diverging from the previously proposed mechanism for pristine heptazine in NAMD simulations. This discovery underscores the significant role of faster proton-coupled electron transfer (PCET) reactions and rapid radiationless relaxation in achieving high photocatalytic efficiency in water splitting. Our work enhances the understanding of the internal mechanism of highly efficient photocatalysts for water splitting and provides a new design strategy for doped GCN.
石墨相氮化碳（g-CN或GCN）尽管面临光生电子-空穴快速复合的挑战，但在光催化水分解方面显示出潜力。在本研究中，我们研究了硼/氧共掺杂对GCN体系光催化产氢性能的影响。采用第一性原理计算和非绝热分子动力学（NAMD）模拟来揭示，与原始GCN相比，共掺杂体系中光生载流子的复合时间可增加16%至64%。利用含时密度泛函理论（TDDFT）方案来选择能量窗口，并在含有水分子的B/O共掺杂庚嗪团簇模型中启动动力学。值得注意的是，我们在共掺杂体系中观察到在60飞秒内水分子中的氢原子发生了高效直接光解离，以及在80飞秒内氢键网络中的质子跳跃，这与之前在NAMD模拟中提出的原始庚嗪机制不同。这一发现强调了更快的质子耦合电子转移（PCET）反应和快速无辐射弛豫在实现高效水分解光催化效率中的重要作用。我们的工作增进了对高效水分解光催化剂内部机制的理解，并为掺杂GCN提供了一种新的设计策略。
