Spectrally Coordinated Plasmonic-Photothermal Photocatalysts for Mineralization of Mixed Indoor VOCs Under White LED Illumination.

Abstract

Indoor volatile organic compounds (VOCs) remain a major health concern, yet conventional photocatalysts show limited effectiveness under low-intensity indoor lighting. Here, a spectrally coordinated plasmonic-photothermal-photocatalytic architecture integrating Cu(II)-grafted TiO₂ (CuT), yolk-shell Au@SiO₂ (AuSi), and reduced graphene oxide sheets (GS) is presented for efficient mixed-VOC mineralization under white light-emitting diode (LED) illumination. Rather than acting as a simple multicomponent composite, this architecture couples partially overlapping but preferential spectral contributions across the LED spectrum: CuT drives visible-light photocatalytic oxidation, AuSi contributes localized surface-plasmon-resonance-induced electric-field enhancement near CuT, and GS converts longer-wavelength photons into localized heat to accelerate interfacial oxidation kinetics. Compared with CuT and binary controls, the composite enhances reactive oxygen species generation, CO₂ formation, and humidity tolerance. CuT/AuSi-GS enables near-stoichiometric CO₂ formation during CH₃CHO/C₇H₈ mixed-VOC mineralization at 10 ppmv within 1 h and maintains over 80% CO₂ yield throughout 168 h of continuous-flow operation at 2 ppmv. Chamber-scale validation in a 64-L reactor indicates the feasibility of VOC mineralization under a dedicated white LED source. Operando infrared spectroscopy traces stepwise oxidation of oxygenated and aromatic VOCs toward CO₂, while wavelength-dependent activity, spectral-overlap analysis, thermal profiling, complementary spectroscopy, and simulations support coordinated energy utilization and deep mineralization under indoor white LED illumination.