Catalytic methane oxidation performance over Pd/γ-Al2O3 catalyst optimized by the synergy of phosphorus and MOx (M = La, Ba and Zr). (1st September 2021)

• Record Type: Journal Article
• Authors: Chen, Xiaohua; Lin, Jia; Zheng, Yong; Zhan, Yingying; Zhang, Wen; Xiao, Yihong; Zheng, Ying; Jiang, Lilong
• Is Part Of: Fuel. Volume 299(2021)
• Publication Date: 2021-09-01
• Subjects: Methane oxidation -- Phosphorus -- Co-addition -- Palladium-based catalysts -- Mesoporous alumina; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2021.120933
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Co-addition of P and MOx (M = La, Ba, Zr) promoted CH4 -oxidizing activity of Pd/Al2 O3 . The crystallinity of PdO was enhanced due to the formation of MOx -PdO interface. MOx promoters induced higher reducing property and richer palladium step sites. Surface-concentration of Oads and the acidity/basicity ratio varied with MOx dopants. Pd/La-PAl manifested the optimum CH4 oxidation activity and moisture-tolerance. Abstract: The focus of this study was to elucidate the synergy of MOx (M = La, Ba and Zr) and phosphorus additives in Pd/ γ -Al2 O3 catalyst towards methane oxidation. It was revealed that the MOx addition as a second promoter positively influenced catalyst performance. The generation of extra MOx -PdO interface facilitated the crystallization of PdO grains as a result of the change in the interfacial tension and then the contact angles of palladium nanoparticles, yielding enhanced reducing property jointly with richer palladium step sites, which preferred catalysts with superior activity. Moreover, MOx dopant provided more surface oxygen species over catalysts due to its electron-donating effect, inhibited the OH/H2 O accumulation and gave lower surface acidity/basicity ratio, improving both activity and moisture-tolerance. Amongst, Pd/La-PAl manifested the optimum activity and excellent durability during 60-h on-stream reaction. It completely catalyzed methane oxidation at around 310 °C after In situ reaction activation and treatment in methane atmosphere.