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

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 exsitu 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.