Facet-heterojunction-based photothermocatalyst CdS-Au-{0 1 0}BiVO4{1 1 0}-MnOx with excellent synergetic effect for toluene degradation

Abstract

• A facet-heterojunction-based strategy was first used to fabricate photothermocatalyst. • Au@CdS and MnO x was respectively anchored on the {0 1 0} and {1 1 0} facets of BiVO 4 crystals. • CdS-Au-{0 1 0}BiVO 4 {1 1 0}-MnO x shows excellent sunlight-driven activity for toluene degradation. • There is a synergetic effect between photocatalysis and thermocatalysis in toluene degradation. • h + , •OH and •O 2 – activate toluene and accelerate the cycle of lattice oxygen in MnO x . For the first time, we exploited a facet-heterojunction strategy to fabricate photothermocatalytic materials, by which CdS-Au-{0 1 0}BiVO 4 {1 1 0}-MnO x was constructed by selectively depositing CdS-Au on {0 1 0} facets and MnO x on {1 1 0} facets of BiVO 4 crystals. The photothermocatalytic performances of the synthesized catalysts were evaluated by using toluene oxidation as a probe reaction. Amongst of all the catalysts, CdS-Au-{0 1 0}BiVO 4 {1 1 0}-MnO x displayed the highest activity for toluene oxidation and near 100% selectivity from toluene to CO 2 under full-spectrum sunlight irradiation. The photothermocatalytic mechnism of CdS-Au-{0 1 0}BiVO 4 {1 1 0}-MnO x was explored by the means of ESR, 18 O 2 isotope labeling experiment, FTIR, and GC–MS. There is a synergistic effect between the photocatalysis and thermocatalysis for toluene degradation, i.e., the active species produced by Z-scheme photocatalyst CdS-Au-{0 1 0}BiVO 4 (h + , •O 2 − and •OH) not only activate toluene but also accelerate the cycle conversion of lattice oxygen and oxygen vacancy in MnO x . This work provides a reference for designing highly efficient photothermocatalytic materials.