Synergy of charge pre-separation and direct Z-scheme bridge in BiVO4{0 4 0}/Ag6Si2O7 photocatalyst boosting organic pollutant degradation

Abstract The rapid recombination and poor redox capability of photoinduced charge carriers seriously impede the photocatalytic activity. Herein, a direct Z-scheme photocatalyst was fabricated by selectively depositing Ag6Si2O7 nanoparticles (NPs) on the {040} facets of BiVO4. Owing to the facet-dependent band structure of BiVO4, the photoinduced electrons and holes can be pre-separated upon photoillumination and transfer to {040} and {110} facets of BiVO4, respectively. A rapid combination of the separated electrons at the {040} facets of BiVO4 with holes of the Ag6Si2O7 NPs then takes place triggering a direct Z-scheme photocatalysis. Such a charge pre-separation triggered by the faceted BiVO4, together with Z-scheme at the interface warrants not only effective photoinduced charge separation but also excellent redox capability owing to the increased redox potential. The photocatalytic rate constant of the optimum BiVO4{040}/Ag6Si2O7 heterostructure is 28.2 and 17.2 times higher than those of pristine BiVO4 and Ag6Si2O7, respectively. This study offers a new insight for constructing direct Z-scheme photocatalysts with high degradation efficiency based on facet-controlled crystals.