Pt position determining efficiency and stability for photocatalytic toluene degradation over Pt decorated TiO₂

Highly durable photocatalytic degradation of gas toluene pollutants is a great challenge due to the easy deactivation of photocatalysts. Herein, we synthesized the Pt embedded at interface of TiO₂ nanocomposites (TiO₂/Pt/TiO₂) and Pt exposed on the surface of TiO₂ nanocomposites (Pt/TiO₂/TiO₂) to investigate the effect of Pt position on the photocatalytic performance of toluene degradation. It was found that the Pt-exposed samples showed inactivation as the reaction progressed because carbonaceous intermediates such as phenol and benzoic acid were observed to be deposited on the exposed Pt to restrain the role of Pt in electron transfer for the production of reactive oxygen species. Whereas, Pt-embedded nanocomposites had excellent activity and stability for toluene degradation and CO₂ production more than 60 h. This was attributed to the protective effect of the TiO₂ outerlayer. The embedded Pt was not easily poisoned by the degradation intermediates, resulting in a good electron transfer and the continuous production of reactive oxygen species for photocatalytic reaction. Therefore, this work provides an efficient approach for designing of the stability of metal-decorated photocatalyst for the highly durable photocatalytic performance.