Synergistic coupling of interface ohmic contact and LSPR effects over Au/Bi24O31Br10 nanosheets for visible-light-driven photocatalytic CO2 reduction to CO

Abstract

The challenge of synergistically optimizing different mechanisms limits the further improvement of plasmon-mediated photocatalytic activities. In this work, an Au/Bi₂₄O₃₁Br₁₀ composite, combining an interface ohmic contact and localized surface plasmon resonance (LSPR), is prepared by a thermal reduction method. The LSPR effect induces the local resonance energy transfer effect and the local electric field enhancement effect, while the interface ohmic contact forms a stronger interface electric field. The novel synergistic interaction between the interface ohmic contact and LSPR drives effective charge separation and provides more active sites for the adsorption and activation of CO₂ with improved photocatalytic efficiency. The optimized 0.6 wt% Au (5.7 nm) over Bi₂₄O₃₁Br₁₀ nanosheets showed an apparently improved photocatalytic activity without any sacrificial reagents, specifically CO and O₂ yields of 44.92 and 17.83 μmol g⁻¹ h⁻¹, and demonstrated superior stability (only lost 6%) after continuous reaction for 48 h, nearly 5-fold enhanced compared to Bi₂₄O₃₁Br₁₀ and a great advantage compared with other bismuth-based photocatalysts.