Plasmonic Double Perovskite LaSrCoMnO₆ Drives Efficient and Selective Photothermal Catalytic Styrene Epoxidation

Localized surface plasmon resonance (LSPR) opens a new avenue for solar-driven organic synthesis. In this work, we synthesize oxygen-vacancy-rich metallic LaSrCoMnO₆ nanoparticles (LSCMn-N) with pronounced LSPR in the visible region. Unlike their microsized counterparts (LSCMn-M), LSCMn-N exhibits a metallic band structure, with enhanced visible light absorption (peaking at 740 nm) and photocurrent density. Under visible light irradiation (λ = 740 nm) and a mild temperature of 70 °C, identified Mn and Co reaction sites promote LSCMn-N to achieve superior photocatalytic styrene epoxidation performance with 99.9% styrene conversion and 91.3% styrene oxide selectivity within 1.5 h, outperforming LSCMn-M by 5.7-fold. Mechanistic studies reveal that the LSPR-induced electric field promotes the generation of carbon-centered radicals via activating styrene by photogenerated holes, while the photogenerated electrons facilitate O₂ reduction to reactive oxygen species. This work highlights the potential of applying plasmonic double perovskites for driving highly efficient and selective solar-powered organic transformations, paving the way for sustainable chemical synthesis.