Solar-Driven Photocatalytic Trichloroethylene Mineralization with High CO₂ Selectivity

Sunlight-driven photocatalytic oxidation, using ambient air as the oxidant, offers a sustainable route for removing chlorinated volatile organic compounds (VOCs) such as trichloroethylene (TCE). Yet, practical implementation is hindered by low reaction rates and undesirable product selectivity. Here, we present a material design strategy that overcomes both challenges. Size-controlled anatase TiO₂ nanocrystals with truncated bipyramid (nanoTBP) morphology achieve exceptional photocatalytic activity for TCE degradation, comparable to rates reported for energy-intensive thermal catalysis, with unoptimized CO₂/CO product ratios. Decorating as-synthesized TiO₂ with Pt nanoparticles significantly enhances the CO₂ selectivity but significantly diminishes the overall reaction rates. To resolve this rate-selectivity trade-off, we integrate Pt/TiO₂ with pristine TiO₂ into an optimized composite photocatalyst, unlocking a tandem pathway that enables both rapid degradation and complete mineralization of TCE to CO₂ under solar irradiation. Taken together, this work establishes a scalable, solar-enabled, materials-based strategy for complete gas-phase mineralization of TCE, with broader implications for novel and sustainable VOC treatment processes.