Micro-environmental modulation of TiO2-supported bimetallic CuAg by carbon quantum dots for promoting photothermal catalytic VOCs degradation

Abstract

Titanium dioxide (TiO₂)-based photocatalysts have been extensively explored, yet their practical application is hindered by limited light absorption and inefficient light–matter interactions. Herein, a robust TiO₂-supported carbon quantum dot (CQD) and CuAg bimetallic nanoparticle (CQDs/CuAg/TiO₂) ternary composite catalyst is developed for photothermal catalytic VOCs degradation. The low-dimensional CQDs modulate the micro-environment at the CuAg–TiO₂ interface, induce electronic redistribution, and amplify the localized surface plasmon resonance (LSPR) effect of CuAg nanoparticles through geometric and electronic synergies. Such micro-environmental modulation optimizes the spectral absorption range, enhances carrier generation/separation efficiency, and promotes hot-electron-mediated VOCs activation ability and photothermal synergy of CQDs/CuAg/TiO₂. The ternary design not only reduces noble metal dependency but also achieves remarkable photothermal synergy. Under simulated three times solar irradiation, CQDs/CuAg/TiO₂ exhibits 4.0 and 1.6 times photothermal toluene mineralization activity higher than TiO₂ and CuAg/TiO₂, respectively. This work provides a cost-effective and scalable approach to designing high-performance photothermal catalysts for VOCs degradation and advancing solar-driven environmental remediation technologies.