Fermi-level-tuned MOF-derived N-ZnO@NC for photocatalysis: A key role of pyridine-N-Zn bond

• Published in: Journal of materials science & technology 2022-06, Vol.112, p.68-76
• Main Authors: Huang, Zheao, Zhou, Qiancheng, Wang, Jieming, Yu, Ying
• Format: Article
• Language: English
• Subjects: DFT calculations; Fermi level; MOF-derived material; Photocatalysis; Pyridine-N-Zn
• ISSN: 1005-0302; 1941-1162
• DOI: 10.1016/j.jmst.2021.10.017

•Tunable nitrogen configurations in N-ZnO@NC was introduced and explored.•Fermi level was reduced successfully to suitable position.•Difference between pyridine-N-Zn and pyrrolic-N-Zn was uncovered by DFT calculation.•Photocatalytic mechanism of N-ZnO@NC was proposed. For photocatalytic materials, the composites formed by metal oxides and heteroatom-doped carbon have outstanding activity. Among them, metal-organic framework (MOF) derived composites, usually composed of metal oxide and nitrogen-doped carbon, is not only simple to prepare, but also have far-exceeding catalytic performance than homogenous semiconductor. However, the relationship between the structure and performance in the photocatalytic system is still not clear. Here, we explored the tunable nitrogen configurations in sample N-ZnO@NC by controlling the thermal conversion of ZIF-8. Crucially, through ex-situ and in-situ XPS characterization, it is found that the ZnO and nitrogen-doped carbon in N-ZnO@NC are connected by C-N-Zn bond, which enhances charge separation efficiency and becomes the origin of superior photocatalytic performance. DFT calculations further reveal the influence of different Zn-bonding nitrogen configurations on the adjusting of Fermi level and electron transfer. This study exhibits that the pyridine-N configuration in MOF-derived material is the main contributor for the improved performance and tunes Fermi level more appropriately than the pyrrolic-N, which can hold the key for future design of next-generation photocatalysts. [Display omitted] .