AUTHOR=Peng Shengpan , Ma Ziran , Ma Jing , Wang Hongyan , Chen Jingyun , Wei Hui , Li Yonglong , Ao Zhimin , Wang Baodong 

TITLE=Influence of carrier effect on Pd/Al2O3 for methane complete catalytic oxidation

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.978698

DOI=10.3389/fchem.2022.978698

ISSN=2296-2646

ABSTRACT=<p>Pd/Al<sub>2</sub>O<sub>3</sub> catalysts modified by different chemical elements (Mg, Si, Ce, and Zr) were tested for methane (CH<sub>4</sub>) catalytic combustion, and PdO nanoparticles loaded on modified Al<sub>2</sub>O<sub>3</sub> were systematically studied. These conditions assess the carrier effects of Pd/Al<sub>2</sub>O<sub>3</sub> and acid strength influences on CH<sub>4</sub> combustion. We observed carrier effects on activation energy through tuning Pd 3d binding energies (BEs) and on pre-exponential factors (A) through Pd dispersion and acidity on supports. When the BE of Pd 3d<sub>5/2</sub> is 337.3 eV, PdO nanoparticles loaded on modified Al<sub>2</sub>O<sub>3</sub> have excellent activity in cracking the C−H bond of CH<sub>4</sub>, which leads to the lowest activation energy (<italic>E</italic><sub><italic>a</italic></sub>), regardless of the size effect of the PdO nanoparticle. Furthermore, a theoretical construction that acid sites on catalysts promote the reversible elementary step (2Pd−OH ↔ Pd−O* + Pd* + H<sub>2</sub>O) right shifts improving the A dependency on the quantity of exposed Pd* and Pd−O*. As a result, Al<sub>2</sub>O<sub>3</sub>, as the carrier, not only modifies the electronic characteristics and size of supported PdO nanoparticles but also participates in the reaction process <italic>via</italic> acid sites on the surface of Al<sub>2</sub>O<sub>3</sub>.</p>