Enhanced Catalytic Ozonation for Eliminating CH<sub>3</sub>SH via Graphene-Supported Positively Charged Atomic Pt Undergoing Pt<sup>2+</sup>/Pt<sup>4+</sup> Redox Cycle
Yajing Huang, Dingren Ma, Weiqi Liu, Dehua Xia, Lingling Hu, Jingling Yang, Peng Liao, Chun He
Abstract
Constructing catalysts with electronic metal–support interaction (EMSI) is promising for catalytic reactions. Herein, graphene-supported positively charged (Pt2+/Pt4+) atomically dispersed Pt catalysts (AD-Pt-G) with PtxC3 (x = 1, 2, and 4)-based EMSI coordination structures are achieved for boosting the catalytic ozonation for odorous CH3SH removal. A CH3SH removal efficiency of 91.5% can be obtained during catalytic ozonation using optimum 0.5AD-Pt-G within 12 h under a gas hourly space velocity of 60,000 mL h–1 g–1, whereas that of pure graphene is 40.4%. Proton transfer reaction time-of-flight mass spectrometry, in situ diffuse reflectance infrared Fourier transform spectroscopy/Raman, and electron spin resonance verify that the PtxC3 coordination structure with atomic Pt2+ sites on AD-Pt-G can activate O2 to generate peroxide species (*O2) for partial oxidation of CH3SH during the adsorption period and trigger O3 into surface atomic oxygen (*Oad), *O2, and superoxide radicals (·O2–) to accomplish a stable, high-efficiency, and deeper oxidation of CH3SH during the catalytic ozonation stage. Moreover, the results of XPS and DFT calculation imply the occurrence of Pt2+ → Pt4+ → Pt2+ recirculation on PtxC3 for AD-Pt-G to maintain the continuous catalytic ozonation for 12 h, i.e., Pt2+ species devote electrons in 5d-orbitals to activate O3, while Pt4+ species can be reduced back to Pt2+ via capturing electrons from CH3SH. This study can provide novel insights into the development of atomically dispersed Pt catalysts with a strong EMSI effect to realize excellent catalytic ozonation for air purification.