Abstract
Simultaneous oxidation of soot and CH(4) 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 CH(4). RuPd/3DOMM-CZO catalyst exhibits excellent catalytic performance and stability during simultaneous soot and CH(4) oxidation. Based on the results of characterizations and theoretical calculations, Ru site in binary Ru-Pd components is responsible for catalyzing NO oxidation to NO(2), which is key step of NO(x)-assisted soot oxidation mechanism, while Pd site can activate the C-H bond of CH(4) for boosting oxidation to CO(2); the catalytic cooperation between Ru and Pd atoms can promote the rate-determining step to realize simultaneous oxidation of soot and CH(4).