Plasmonic gold nanostars conjugated poly(heptazine imide) for photocatalytic H2O2 production from O2 reduction

Abstract

Recent advances in photocatalytic systems for H₂O₂ production have led to improvements in both efficiency and selectivity; however, the practical application of current photocatalysts remains limited by low H₂O₂ production rates, poor long-term stability, and challenges in scalability. In this study, we present a novel photocatalyst based on the integration of gold nanostars (AuNSs) into poly(heptazine imide) (PHI) resulting in a system that is highly efficient for H₂O₂ production. The resulting AuNSs–PHI catalyst achieved a remarkable H₂O₂ generation rate of 286.95 mM g⁻¹ h⁻¹ under solar irradiation, utilising O₂ reduction coupled with isopropanol oxidation. This enhanced performance is primarily attributed to localized surface plasmon resonance (LSPR) effects from the embedded gold nanostars, which significantly boost light absorption and charge separation efficiency. The critical role of the optimized nanostructure was further validated through time-dependent density functional theory (TDDFT) calculations on a gold cluster (Au₂₀) adsorbed onto PHI, providing theoretical insight into the observed experimental H₂O₂ production enhancement. These findings demonstrate the potential of plasmon-enhanced photocatalysis as a viable pathway for sustainable and scalable H₂O₂ production.