Crystal facet engineering of BiVO4/CQDs/TPP with improved charge transfer efficiency for photocatalytic water oxidation

BiVO4 as an outstanding semiconductor material has been extensively employed in artificial photosynthesis, but it usually suffers drawbacks such as poor electron transportation and slow kinetics of oxygen evolution. Herein, we construct a novel ternary BiVO4/CQDs/TPP photocatalysts for photocatalytic water oxidation by controlling the preferential growth of BiVO4 (010) crystal surface after introducing TPP. The BiVO4/CQDs/TPP shows an enhancement of the water oxidation rate of 352.5 mu mol g- 1h- 1 compared with the bare BiVO4 (113.7 mu mol g1h-1), which is due to the more efficient interfacial electron-hole transfer between TPP and BiVO4 via CQDs as an electron mediator as well as preferentially exposed (010) facets of BiVO4. The efficient photogenerated charge behavior is confirmed by the surface photovoltage and transient absorption spectroscopy. Density functional theory calculation reveals that water dissociation on the (010) facet surface is more energetically favorable for BiVO4/CQDs/TPP-60 than that of the pristine BiVO4. The present work affords deep understanding of the crystal morphology and facet engineering for BiVO4-based photocatalysts.

Automated summary

By introducing TPP to control the preferential growth of BiVO4 (010) crystal surface, a novel ternary BiVO4/CQDs/TPP photocatalyst was constructed, showing an enhanced water oxidation rate with efficient electron-hole transfer between TPP and BiVO4 via CQDs as electron mediator. The surface photovoltage and transient absorption spectroscopy confirmed the efficient charge behavior, and density functional theory calculation revealed the more energetically favorable water dissociation on the (010) facet surface of BiVO4/CQDs/TPP-60 compared to pristine BiVO4.