Trap engineering in violet antimony phosphorus: Modulating photoelectron transfer pathways for enhanced photocatalytic hydrogen evolution

Modulating the photoelectron transfer pathways offers a promising strategy to improve electron-hole separation efficiency, thereby enhancing photocatalytic reactions. Herein, trap engineering has been employed in violet antimony phosphorus to modulate its photoelectron transfer pathways, inhibiting the recombination of photo-generated electron-hole pairs and significantly enhancing its photocatalytic hydrogen evolution performance. Shallow trap states near the conduction band minimum have been introduced into violet antimony phosphorus (VPSb) by both phosphorus and antimony vacancies to obtain VPSb-v through a plasma treatment. The introduction of trap states to VPSb and VPSb-v has significantly reduced the recombination rate of photo-generated carriers. The decay time of photo-generated electrons from trap state to the cocatalyst Pt was found to reduce (6892 ps of VPSb to 542 ps of VPSb-v) by time-resolved absorption spectroscopy, while the decay time to ground state was found to significantly increase (235 ps of VPSb to 10982 ps of VPSb-v). The trap state introduced by vacancies has been demonstrated to serve as an electron reservoir, where some electrons were transferred directly to co-catalyst and the other one through trap state to co-catalyst. The photocatalytic hydrogen production rate of VPSb-v (5216 μmol g⁻¹ h⁻¹) was much higher than that of reported non-metal semiconductor photocatalysts.