Construction of flower sphere Bi4O5Br2/Bi2WO6 heterojunction for highly selective CO evolution in photocatalytic CO2 reduction without sacrificial reagents

Abstract

Given the increasing interest in converting CO₂ into clean energy through photocatalytic processes, a Bi₄O₅Br₂/Bi₂WO₆ heterojunction photocatalyst was successfully constructed via a hydrothermal process combined with an in situ growth technique for efficient CO₂ photoreduction. Without sacrificial agents, the composite material 20Bi₄O₅Br₂/Bi₂WO₆ (20BOB/BWO) demonstrated superior photocatalytic activity. The generation rates of CO and CH₄ reached 25 µmol·g⁻¹·h⁻¹ and 4.6 µmol·g⁻¹·h⁻¹, respectively; notably, the CO yield was significantly higher than that of pure Bi₄O₅Br₂ and Bi₂WO₆. Such enhancement originated from the type-II interfacial charge transfer mechanism, which facilitated efficient spatial charge separation and consequently led to a remarkable improvement in the composite’s catalytic efficiency.