Octahedral Layered Birnessite (OL) Supported Ag Catalysts: Characterization and Catalytic Oxidation of CO

Abstract:

Octahedral layered birnessite (OL) was synthesized by redox method, and OL supported Ag catalysts (xAg/OL, x = 0.1wt%, 0.2wt%, 0.3wt%, 0.5wt%) were prepared by ion exchange method. Then catalysts were characterized by XRD, SEM, BET, H₂-TPR, TG, O₂-TPD and in-situ DRIFTS, while the catalytic activity of CO was evaluated. Among xAg/OL samples, the 0.3Ag/OL exhibited the best catalytic activity for CO oxidation (T₅₀ = 105 ^oC and T₉₀ = 135 ^oC). The results show that the chemical adsorption of oxygen, the low-temperature reducibility and the strong interaction between the Ag species and OL are related to the excellent catalytic activity of xAg/OL. The reaction mechanism was studied by in-situ DRIFTS. First, O₂ was adsorbed and activated on the oxygen vacancies of xAg/OL, then formed oxygen free radical attacked the adsorbed CO and produced CO₂, subsequently CO₂ desorbed from the catalyst surface. Oxygen vacancies was supplemented by gas O₂, thus circulating.

• Periodical: Solid State Phenomena (Volume 304)
• Pages: 35-44
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.304.35
• Online since: May 2020
• Authors: Meng Yue Chen, Ning Dong, Qing Ye*, Zhi Dan Fu
• Keywords: Ag, Catalytic Oxidation of CO, Characterization, OL, Reaction Mechanism

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