Global Climate Research

Overview

Catalytic oxidation removes toxic organochlorine pollutants by converting them to less harmful products via surface redox reactions and bond-cleaving steps. Effective catalysts must balance oxygen mobility and acidity to break C–Cl bonds while avoiding undesirable by-products.

Catalytic oxidation of chlorinated volatile organic compounds (CVOCs) relies on catalysts that provide active oxygen species for oxidation and acid sites for C–Cl bond activation. CeO2-based materials are widely used for oxidation because of their oxygen storage/release ability, and noble metal promoters (like Pt) can tune redox properties and surface oxygen activity.

This study addressed how varying Pt content affects the redox–acidity synergy and consequent catalytic performance of Pt-HSiW/CeO2 catalysts for oxidation of chlorinated volatile organic compounds (CVOCs). Here we show that tuning Pt loading to 2.0 wt% on HSiW/CeO2 produced the best redox–acidity synergy, giving the highest Ce3+ fraction, abundant surface adsorbed oxygen, retained weak/medium-strong acid sites, and optimal catalytic oxidation of chlorobenzene to CO2 and H2O.

Previous work has emphasized either redox activity (oxygen vacancies, Ce3+/Ce4+ cycling) or acidity separately for CVOC oxidation. Here we show that an optimal balance (2.0 wt% Pt) simultaneously maximizes surface adsorbed oxygen and preserves sufficient weak/medium-strong acid sites, outperforming catalysts with lower or higher Pt loadings and demonstrating that more Pt is not always better. Chlorinated VOCs are persistent, toxic pollutants generated by many industrial processes; efficient catalytic destruction mitigates health and environmental risks. Understanding how metal loading tunes catalyst redox and acidity helps develop more effective abatement technologies.

The results can guide design of Pt-doped CeO2 catalysts for industrial and environmental catalytic oxidation systems to abate chlorinated volatile organic compounds (CVOCs) from waste streams and flue gases, improving air quality and regulatory compliance. Future work should examine long-term stability and chlorine poisoning resistance of Cat-2.0 under realistic flue-gas conditions, extend testing to diverse CVOCs, and use theoretical (DFT) studies to resolve atomic-scale mechanisms of redox–acid synergy.