Flowerlike BiOCl nanospheres fabricated by an in situ self-assembly strategy for efficiently enhancing photocatalysis

For semiconductor-based photocatalytic reactions, defect engineering has been proven as an efficient approach to enhance the photocatalytic performance. In this work, a synergistically PVP/EG-assisted in situ self-assembly strategy has been successfully developed for preparing flowerlike BiOCl nanospheres (NSP) assembled by ultrathin nanosheets (thickness of 3.8 nm) with abundant oxygen vacancies (OVs). During the hydrothermal process, PVP plays a template role in controlling the orientation of the crystallite growth, leading to the forming of nanosheets. Meanwhlie, ethylene glycol would induce the self-assembly of nanosheets into a loose hierarchical architecture duo to its stereo-hindrance effect. NSP achieves a twice higher photocatalytic conversion of benzylamine than BiOCl nanosheets (NST) under visible light. XPS, ESR, NH3-TPD results manifest that NSP possesses more active sites including OVs and unsaturated Bi atoms than NST, because of avoiding the accumulation of ultrathin nanosheets. In situ FTIR reveals that benzylamine molecules can be chemisorbed and activated on BiOCl interfaces via forming -N center dot center dot center dot Bi- species. The OVs can facilitate the forming of superoxide radicals (center dot O-2(-)), achieving the selective photooxidation. Finally, a possible synergetic mechanism based on the interaction of reactants and catalyst interfaces was proposed to illustrate the photocatalytic process at the molecular level. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

Defect engineering has been proven as an efficient approach to enhance the photocatalytic performance in semiconductor-based photocatalytic reactions. In this work, a synergistically PVP/EG-assisted in situ self-assembly strategy was successfully developed for preparing flowerlike BiOCl nanospheres with abundant oxygen vacancies. The nanospheres showed a twice higher photocatalytic conversion of benzylamine than BiOCl nanosheets under visible light, attributed to more active sites and improved selectivity for photooxidation.