1. Highly Active and Stable Pd/MgAl2O4 Catalysts for Methane Catalytic Combustion
- Author
-
Jie Li, Jieying Cai, Yan Zhang, Peng Wang, Xuehai Wang, Xiangchen Fang, Yunbo Yu, and Wenpo Shan
- Subjects
metal–support interaction ,methane catalytic combustion ,MgAl2O4 spinel ,oxygen defects ,Pd particle sizes ,Environmental technology. Sanitary engineering ,TD1-1066 ,Renewable energy sources ,TJ807-830 - Abstract
Mesoporous MgAl2O4 is synthesized via a novel sol–gel combustion method and the concentration of oxygen defects on the surface is modulated through varying the calcination temperature (850, 900, 1000, and 1100 °C). Notably, the 1Pd/MgAl2O4‐1000 catalyst exhibits superior catalytic activity and stability. The turnover frequency (TOF) for 1Pd/MgAl2O4‐1000 is 0.079 and 0.058 s−1 under dry conditions (300 °C) and wet conditions (380 °C), respectively. The results of H2 temperature‐programmed reduction and X‐Ray photoelectron spectroscopy reveal that the principal active species within the Pd/MgAl2O4‐y catalyst is PdO. Specifically, the Pd–MgAl2O4‐1000 catalyst exhibits the lowest temperature reduction peak (120 °C) and the highest redox capability. Additionally, O2 temperature‐programmed oxidation further elucidates that PdOx species in the Pd/MgAl2O4‐1000 catalyst is prone to decomposition and the resultant palladium metal is readily reoxidized. Consequently, the rapidity of the redox cycle between PdO and Pd0 emerges as a pivotal factor in CH4 catalytic combustion. Furthermore, a correlation analysis among catalyst particle size, oxygen defect concentration, and TOF is conducted. The findings illustrate a distinct volcano‐shaped curve in the relationship between oxygen defect concentration and TOF for the 1Pd/MgAl2O4−y catalysts. A comparable trend is also evident in the correlation between Pd particle size and TOF.
- Published
- 2024
- Full Text
- View/download PDF