Boosting visible light driven gas–solid phase photocatalytic reduction of CO2 on BiOCl microspheres by enhanced carrier transportation through lattice structure modification

BiOCl powders with different amounts of thiourea addition (0, 25 mg, 50 mg, 100 mg versus 8 mmol Bi(NO3)3, denoted as BOC, BOC-S1, BOC-S2, BOC-S3) in precursor were prepared by solvothermal method. In this work, thiourea generated modification of lattice structure, stimulating shrinkable Bi-O bond rather than S element doping or composite structure forming. Shrinkable Bi-O bond generated enhanced interaction between [Bi2O2]2+ and adjacent Cl-, causing stronger inner electric field. Shorter Bi-O bond endows valence band(VB) more Cl 3p component, enhancing Cl 3p dominance. With intrinsic Bi 6p dominant conduction band, holes could be transferred to VB on Cl while electrons be transferred to CB on Bi under stronger inner electric field, performing heterojunction like efficient charge separation and transfer. Prominent promotion on CO2 photocatalytic reduction was thus achieved due to improved charge separation and transfer efficiency, where BOC-S2 reach about 5.6 times higher CH4 yield than BOC with CH4 selectivity increasing from 80.673 % (BOC) to 96.473 % (BOC-S2), certifying successful CO2 reduction ability promotion through lattice structure modulation.