Platinum−Copper Bimetallic Nanoparticles Supported on TiO2 as Catalysts for Photo−thermal Catalytic Toluene Combustion

Oxidation of toluene into CO2 and H2O under mild conditions via a photo-promoted catalytic process has been regarded as a promising tactic to solve the toluene pollution issues in air. In this work, we examined the performance of Pt–Cu/TiO2 nanocatalysts with tunable mass ratios between Pt and Cu elements for photocatalytic, thermocatalytic, and photo–thermal catalytic degradation of toluene. In the photo–thermal catalytic process, 80% of the inlet toluene could be decomposed over Pt0.4 wt %Cu0.1 wt %–TiO2 catalyst at 77 °C under light irradiation, while 100 °C was needed for Pt0.5 wt %–TiO2 to achieve the same catalytic efficiency. The greatly enhanced activity could be ascribed to the synergistic effects arising from photothermal effects of the high dispersion of PtCu alloy nanoparticles, intimate interaction between the metal elements, and the photoexcitation of TiO2. In the photocatalytic process, the highest photocatalytic toluene conversion rate was obtained on the PT-4 catalyst (55%) and there was a negligible conversion rate (0.38%) of toluene under thermocatalytic conditions at 110 °C, delineating that the efficiency of photo–thermal catalytic degradation of toluene was much higher than that of a thermocatalytic or a photocatalytic process, illustrating the synergistic effects between light irradiation and heat. This work highlights the high photo–thermal catalytic toluene degradation performance of PtCu alloy nanoparticles and the synergistic effects of light irradiation and heat.