Promoting Formation and Suppressing Decomposition of H₂O₂ via Photocarrier Flow at Au@TiO₂ Interfaces

Hydrogen peroxide (H₂O₂) is an attractive green oxidant and energy carrier, but its industrial production remains energy- and resource-intensive. Photocatalytic synthesis from O₂ and H₂O offers a safer and more sustainable alternative, yet its efficiency is hampered by sluggish formation and rapid decomposition pathways. Here, we demonstrate a plasmon-engineered strategy to overcome both challenges using Au@TiO₂ core-shell nanostructures. The nanocubic Au@TiO₂ (NC@TiO₂) achieves a remarkable H₂O₂ production rate of 350.5 mM h^-1g^-1 under full-spectrum irradiation -1.6 times higher formation and 47% lower decomposition compared to bare TiO₂. Spectroscopic analysis and simulations reveal that localized surface plasmon resonance (LSPR) in the Au core orchestrates photocarrier dynamics: electrons generated in TiO₂ are funneled to Au sites to drive O₂ reduction, while plasmonic hot electrons neutralize TiO₂ holes that would otherwise decompose H₂O₂. The morphology dependence of this effect is evident: NC@TiO₂ with stronger LSPR outperforms rhombic dodecahedral Au@TiO₂. These results establish plasmon-mediated charge steering as a powerful tool to enhance both efficiency and selectivity in solar-to-chemical conversion, providing a design principle for next-generation photocatalysts.