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

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 dots (CQDs) and CuAg bimetallic nanoparticles (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, 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.