催化作用
碱土金属
无机化学
氧化物
金属
钯
化学
尖晶石
氧气
材料科学
作者
Tang Yang,Jia Lin,Xiaohua Chen,Yifan Zheng
标识
DOI:10.1016/j.jallcom.2022.164065
摘要
Aiming to manipulate the properties of Pd/Al 2 O 3 catalysts towards CH 4 oxidation, trace of Zn and alkaline-earth metal (X = Mg, Ca, Sr and Ba) were dual-doped into mesoporous alumina. This was mainly inspired by their multi-functionality, in terms of the feature of semiconductor structure from amphoteric oxide ZnO, the higher metallicity and electron-donating effect from alkaline-earth metals, and the ability from both Zn and alkaline-earth metals to generate spinel phase with alumina. Eventually, the electron density throughout oxygen and metal atoms underwent rearrangement, the interfacial interaction and the surface work function of catalysts were altered. This in turn gave the distinction in the nanoparticle sizes and reducibility of palladium oxides, surface-concentration and stability of active PdO, distribution of surface oxygen species, and surface acid-base functionalities along the series of catalysts. Results demonstrated that the trade-off of these entire properties allowed Pd/ZnMg-MA with maximum light-off activity, whilst affording minimum drop in methane conversion over both Pd/ZnMg-MA and Pd/ZnBa-MA not only during long-term online test but also when water was injected into the feed. • Dual-doping of Zn and alkaline-earth metal tailored catalytic behaviors of Pd/Al 2 O 3 . • ZnAl 2 O 4 and XAl 2 O 4 (X: Mg, Ca, Sr, Ba) spinel interface were created over Pd/Al 2 O 3 . • The electron densities along oxygen and metal atoms over catalysts were rearranged. • Pd/MgZn-MA afforded maximum initial activity for CH 4 oxidation. • Mg/Zn and Ba/Zn dual-doping gave higher durability and resistibility against water.
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