Electronic Modulation Engineering of Pt-Modified TiO2 Nanotube-Confined Co Catalyst for Efficient Low-Temperature Catalytic Oxidation of CH3SH.

Abstract

Methanethiol (CH3SH) is a typical malodorous volatile organic pollutant, and its efficient low-temperature catalytic degradation remains both an urgent priority and a formidable challenge in odor abatement. Herein, we leveraged the unique curved surface architecture of titanium dioxide nanotubes ((TiO2 NTs) and developed a targeted electronic-modulation strategy in which cobalt (Co) species were confined within the nanotube channels via vacuum impregnation, followed by the photodeposition of platinum (Pt) onto the outer surface as an electron-withdrawing layer to yield a composite catalyst (Co@TiO2 NTs-Pt). Catalytic performance evaluations showed that Co@TiO2 NTs-Pt exhibits excellent low-temperature activity toward CH3SH oxidation, achieving approximately 95% conversion at room temperature and enabling complete oxidation of sulfur-containing intermediates at even lower temperatures than those required with Co@TiO2 NTs. Comprehensive characterization indicated that depositing Pt on the exterior surface enhances the electron-deficient environment within the nanotube cavity and induces surface lattice distortion, thereby raising the oxidation state of the confined Co species and increasing the concentration of oxygen vacancies. Density functional theory (DFT) calculations further confirmed that this electronic-modulation strategy significantly strengthens CH3SH chemisorption and activation on the catalyst surface. Furthermore, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) elucidated the reaction pathways governing CH3SH oxidation over the catalyst surface. Overall, this study deepens the understanding of electronic confinement effects in TiO2 NTs and provides a theoretical basis and technical guidance for designing advanced catalysts for the efficient low-temperature abatement of malodorous organic pollutants.

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