Rh/CeO_(2) composites prepared by combining dealloying with calcination as an efficient catalyst for CO oxidation and CH4 combustion

In this paper,a series of Rh/CeO_(2) catalysts with three-dimensional porous nanorod frameworks and large specific surface area were prepared by chemical dealloying Al–Ce–Rh precursor alloys and then calcining in pure O_(2).The effects of the Rh content and calcination temperature on CO oxidation and CH_(4) combustion were studied,and the results reveal that the Rh/CeO_(2) catalysts produced by dealloying melt-spun Al_(91.3)Ce_(8)Rh_(0.7) alloy ribbons and then calcining at 500℃ exhibit the best catalytic activity,the reaction temperatures for the complete conversion of CO and CH_(4) are as low as 90 and 400℃,respectively.Furthermore,after 150 h of continuous testing at high concentrations of H2O and CO_(2),the nature of the catalyst is not irreversibly destroyed and can still return to its initial level of activity.This excellent catalytic activity is attributed to a portion of Rh being uniformly distributed on the CeO_(2) nanorod surface in the form of nanoparticles,forming strong Rh–CeO_(2) interfacial synergy.Another portion of Rh permeated into the CeO_(2) lattice,which results in a significant increase in the number of oxygen vacancies in CeO_(2),thus allowing more surface active oxygen to be adsorbed and converted from the gas phase.Moreover,the catalytic reaction can proceed even in an oxygen-free environment due to the excellent oxygen storage performance of the Rh/CeO_(2) catalyst.