Pt Nanoparticles Supported on WO₃ Microparticles as the Catalyst for the Oxidation of Toluene

The search for the proper catalysts for the effective elimination of harmful volatile organic compounds is still considered one of the major problems in environmental remediation. The present study explains the effect of loading and sharp edges of Pt nanosized particles (NPs) on the reactivity of the Pt/WO₃ nanostructured catalyst toward low-temperature toluene oxidation. The as-synthesized nanostructured material was characterized by structural, textural, and elemental analyses using X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, STEM-mapping, X-ray photoelectron spectroscopy, BET, H₂-TPR, Raman spectroscopy, and ICP-AES analysis. Pt nanoparticles having diameters of 5–10 nm, supported on 3D WO₃, were fruitfully prepared using a simple surfactant-assisted preparation route. It was observed that 1.5% Pt loading exhibits the optimum loading to obtain the best catalytic performance (T₉₀ = 164 °C) with high regeneration capability under humid conditions and excellent catalytic durability for 50 h with various concentrations of toluene. In situ DRIFT spectroscopy can gain an accurate understanding of the proper mechanism of the toluene oxidation reaction using Pt catalysts. Density functional theory calculations were employed to study the toluene activation over the Pt₁₃/WO₃ (100) catalyst and showed the methyl C–H activation and phenyl ring oxygen insertion to be energetically favorable. The understanding of this work also reveals that sharp edges and the generation of robust interactions between metal and support nanoparticles act as the driving force behind the high catalytic activity and good stability toward low-temperature catalytic oxidation of toluene.