Efficient α-MnO2 with (2 1 0) facet exposed for catalytic oxidation of toluene at low temperature: A combined in-situ DRIFTS and theoretical investigation. (January 2021)

• Record Type: Journal Article
• Authors: Huang, Jing; Fang, Ruimei; Sun, Yanjuan; Li, Jieyuan; Dong, Fan
• Is Part Of: Chemosphere. Volume 263(2021)
• Publication Date: 2021-01
• Subjects: Catalytic oxidation -- Toluene -- Crystal facet -- α-MnO2 -- DFT calculation; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.128103
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The α-MnO2 catalysts with (1 1 0), (2 1 0) and (3 1 0) crystal facets exposed were prepared via hydrothermal method and studied for the catalytic oxidation of toluene. Some characterization technologies and DFT theoretical calculation were combined to analyze the as-synthesized catalysts. The α-MnO2 catalyst exposed with the (2 1 0) plane displayed best catalytic performance and attained complete toluene conversion at 140 °C. The O2 -TPD and XPS results exhibited the amount of surface lattice oxygen on α-MnO2 -210 catalyst was largest. Lower accumulation and faster disintegration of intermediates which was characterized by in-situ DRIFTS could be discovered on the surface of α-MnO2 -210 catalyst. The results of DFT calculation showed that the unique atomic arrangement of α-MnO2 -210 catalyst enhanced the charge separation and conversion, promoting the formation of active oxygen and the activation of toluene. The Ea of α-MnO2 -210 catalyst was 24.75 kJ mol −1, lowest among the three catalysts. This work highlights the facet effects on catalytic property and provides new insight into the understanding of catalytic oxidation reaction mechanism of toluene. Graphical abstract: The figures are toluene removal efficiency of α-MnO2 with different exposed facets catalysts and proposed mechanism of toluene degradation pathway on α-MnO2 . Image 1 Highlights: The exposed facet played a pivotal role in tuning the catalytic performance. α-MnO2 -210 catalyst exhibited best catalytic activity in complete toluene oxidation. Unique atomic arrangement of α-MnO2 -210 enhances the activation of toluene.