Fu Gang, Song Xiaozhuo, Zhao Siwei, Zhang Jiaxu
School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China.
Molecules. 2022 Nov 6;27(21):7611. doi: 10.3390/molecules27217611.
Nonmetallic co-doping and surface hole construction are simple and efficient strategies for improving the photocatalytic activity and regulating the electronic structure of g-CN. Here, the g-CN catalysts with B-F or B-S co-doping combined with nitrogen vacancies (N) are designed. Compared to the pristine g-CN, the direction of the excited electron orbit for the B-F-co-doped system is more matching (N→C), facilitating the separation of electrons and holes. Simultaneously, the introduced nitrogen vacancy can further reduce the bandgap by generating impurity states, thus improving the utilization rate of visible light. The doped S atoms can also narrow the bandgap of the B-S-N-co-doped g-CN, which originates from the p-orbital hybridization between C, N, and S atoms, and the impurity states are generated by the introduction of N vacancies. The doping of B-F-N and B-S-N exhibits a better CO reduction activity with a reduced barrier for the rate-determining step of around 0.2 eV compared to g-CN. By changing F to S, the origin of the rate-determining step varies from *CO→*COOH to *HCHO→*OCH, which eventually leads to different products of CHOH and CH, respectively.
非金属共掺杂和表面空穴构建是提高g-CN光催化活性和调节其电子结构的简单有效策略。在此，设计了具有B-F或B-S共掺杂并结合氮空位（N）的g-CN催化剂。与原始g-CN相比，B-F共掺杂体系中激发电子轨道的方向更匹配（N→C），有利于电子和空穴的分离。同时，引入的氮空位可通过产生杂质态进一步降低带隙，从而提高可见光利用率。掺杂的S原子也可使B-S-N共掺杂的g-CN的带隙变窄，这源于C、N和S原子之间的p轨道杂化，且杂质态由N空位的引入产生。与g-CN相比，B-F-N和B-S-N的掺杂表现出更好的CO还原活性，速率决定步骤的势垒降低了约0.2 eV。通过将F换成S，速率决定步骤的起源从*CO→COOH变为HCHO→*OCH，最终分别导致不同的产物CHOH和CH。
