Degradation of Formaldehyde over MnO₂/CeO₂ Hollow Spheres: Elucidating the Influence of Carbon Sphere Self-Sacrificing Templates.

ABSTRACT: Here, we prepare a MnO₂/CeO₂ hollow sphere catalyst using the carbon sphere as a self-sacrificing template for formaldehyde (HCHO) removal. In the feed gas of 20 ppm of HCHO (balanced by N₂) + 20 vol % O₂, a HCHO removal efficiency of 70% was achieved at 20 °C and full conversion was reached at around 47 °C at GHSV = 50,000 mL (g_cat h)^-1 for MnO₂/CeO₂ hollow spheres. The catalytic performance and structural and chemical properties of MnO₂/CeO₂ hollow spheres for the removal of core carbon spheres were explored, and the influence of using the carbon sphere as a self-sacrificing template was proved by comparing with carbon@MnO₂/CeO₂ (a core carbon sphere with a MnO₂/CeO₂ shell) and nonmorphologic MnO₂/CeO₂. The properties of the MnO₂/CeO₂ hollow spheres are significantly improved compared to carbon@MnO₂/CeO₂ (removal efficiency of 45% at 150 °C) and MnO₂/CeO₂ (removal efficiency of 46% at 20 °C) as a result of an evolution in the interaction between Mn/Ce and carbon. This increase in the interaction strength seems to (i) increase the oxygen vacancy, (ii) promote the oxygen species mobility, and (iii) improve the chemical stability of the MnO₂/CeO₂ hollow spheres. We believe that these results are beneficial to the fabrication of binary transition metal oxides and applications of them in HCHO removal.

SUBMITTER: Zhu C 

PROVIDER: S-EPMC8717371 | biostudies-literature | 2021 Dec

REPOSITORIES: biostudies-literature