Catalytic cooperation between Ru and Pd atoms on hierarchical porous Ce-based oxide for boosting engine exhaust purification
Linsheng Xu, Tian Qin, Yuanfeng Li, Hao Guo, Qiao Hu, Jing Xiong, Yaxiao Ma, Peng Zhang, Xiaolin Yu, Xi Liu, Yunpeng Liu, Zhen Zhao, Jian‐Ping Zou, Yuechang Wei
Abstract
Simultaneous oxidation of soot and CH4 emitted from natural gas-diesel dual fuel engine is a new challenge. Herein, a robust catalyst of binary Ru-Pd components supported on three-dimensional ordered macro-mesoporous cerium-zirconium oxide (RuPd/3DOMM-CZO) is elaborately constructed. Ordered macro-mesopore structure in novel hierarchical porous cerium-zirconium oxide can respectively enhance mass transfer of soot and gaseous reactants, and binary Ru-Pd active components can improve activation for NO and CH4. RuPd/3DOMM-CZO catalyst exhibits excellent catalytic performance and stability during simultaneous soot and CH4 oxidation. Based on the results of characterizations and theoretical calculations, Ru site in binary Ru-Pd components is responsible for catalyzing NO oxidation to NO2, which is key step of NOx-assisted soot oxidation mechanism, while Pd site can activate the C-H bond of CH4 for boosting oxidation to CO2; the catalytic cooperation between Ru and Pd atoms can promote the rate-determining step to realize simultaneous oxidation of soot and CH4. Simultaneous oxidation of soot and CH4 is challenging in dual-fuel engines. This study introduces a Ru-Pd/3D macromesoporous Ce-Zr oxide catalyst, significantly enhancing oxidation via cooperative Ru (NO activation) and Pd (CH4 activation) sites.