Synergistic combination of active Pt species and light-driven photothermal catalysis for highly efficient toluene oxidation†

Abstract

Energy shortage and environmental pollution problems force us to find low-energy consumption methods to deal with volatile organic compounds (VOCs). In this work, Pt-P25 was synthesized through a simple wet impregnation method and calcination method. The study showed that different calcination temperatures and calcination atmospheres affected the activation state of Pt species, showing significant differences in the photothermal catalytic toluene oxidation reaction efficiency. The Pt-P25-800N sample activated in a nitrogen atmosphere at 800 °C exhibits better activity compared to other samples, achieving a toluene conversion rate of 95% and mineralization rate of 65% under a light intensity of 400 mW cm⁻². Characterization results demonstrate that low-valent Pt species are positively correlated with toluene oxidation activity and play a major role in the reaction. The ultraviolet (UV), visible (vis) and infrared (IR) components in the spectrum all contribute to the toluene oxidation process. The catalytic bed is heated to the required temperature mainly through thermal effects, thus overcoming the reaction energy barrier. The traditional photocatalytic process over TiO₂ also plays an auxiliary enhancement role. Due to the efficient conversion capability of the active sites, Pt-P25-800N achieves long-term stability of at least 50 hours under low light intensity input and water vapor conditions, accompanied by minimal accumulation of intermediate products. The above results reveal that the comprehensive effect between active Pt species and photothermal catalysis jointly achieves efficient degradation of VOCs and alleviates the energy and environmental crisis.