Halogen surface modification induced strong interfacial electric field for efficient photocatalytic H2O2 generation

Abstract

Bi2O2(NO3)(OH) (BON) and g-C3N4 (CN) as highly efficient semiconductor photocatalytic materials, have attracted much attention in the field of environmental remediation and clean energy production because of their unique two-dimensional layered structures. However, the narrow light absorption range of a single semiconductor and the low separation efficiency of photoexcited electron-hole pairs seriously restrict their photocatalytic activity. Based on these key scientific issues, we take BON/CN heterojunction system as the research model to explore the effect of promoting interfacial charge separation and transport on photocatalytic H2O2 production via halogen surface modification on BON. X-ray photoelectron spectroscopy, in-situ Kelvin-probe force microscopy and photoelectrochemical measurements demonstrate that the formation of BON-I/CN Z-scheme junction renders efficient charge separation and migration, considerably contributing to the rapid H2O2 generation via a two-step one-electron route, in addition to the enhanced photoabsorption. Thus, BON-I1/CN exhibited the highest photocatalytic H2O2 production rate of 481.9 µmol L−1 h−1, much higher than that of pure BON, CN, BON/CN, BON-Cl1/CN and BON-Br1/CN. This work provides an effective strategy for efficiently promoting photocatalytic production of H2O2.