In-situ decoration of metallic Bi on BiOBr with exposed (110) facets and surface oxygen vacancy for enhanced solar light photocatalytic degradation of gaseous n-hexane

Photocatalytic degradation of gaseous pollutants on Bi-based semiconductors under solar light irradiation has attracted significant attention. However, their application in gaseous straight-chain alkane purification is still rare. Here, a series of Bi/BiOBr composites were solvothermally synthesized and applied in solar-light-driven photocatalytic degradation of gaseous n-hexane. The characterization results revealed that both increasing number of functional groups of alcohol solvent (from methanol and ethylene glycol to glycerol) and solvothermal temperature (from 160 and 180 to 200 degrees C) facilitated the in-situ formation of metallic Bi nanospheres on BiOBr nanoplates with exposed (110) facets. Meanwhile, chemical bonding between Bi and BiOBr was observed on these exposed facets that resulted in the formation of surface oxygen vacancy. Furthermore, the synergistic effect of optimum surface oxygen vacancy on exposed (110) facets led to a high visible light response, narrow band gap, great photocurrent, low recombination rate of the charge carriers, and strong center dot O-2(-) and h(+) formation, all of which resulted in the highest removal efficiency of 97.4% within 120 min of 15 ppmv of n-hexane on Bi/BiOBr. Our findings efficiently broaden the application of Bi-based photocatalysis technology in the purification of gaseous straight-chain pollutants emitted by the petrochemical industry. (c) 2020, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.