Oxygen spillover effects induced by Rh-modification on the low-temperature oxidation of CO over Cu-incorporated zeolite A studied by the forced oscillating reaction method

Abstract

In order to develop a CO oxidation catalyst exhibiting at a low-temperature range, an Rh-modified Cu-incorporated zeolite A catalyst was investigated. Supported 8.6 wt.% Cu catalysts were prepared by different procedures. One (Cu/SiO 2) was prepared by ordinary incipient impregnation method using SiO 2 as the support. Another (Cu–A) was prepared by incorporation of Cu into the framework of zeolite A by using Cu nitrate in the mixed solution for crystallization. Only 1 wt.% Rh to Cu was added to Cu–A. The redox properties were measured by temperature-programmed reduction (TPR) and temperature-programmed oxidation (TPO) and it was found that Cu in Cu–A has much higher dispersion than in Cu/SiO 2, and by Rh addition not only reduction of oxidized Cu–A but also reduced Cu–A enhanced reduction and oxidation, respectively. The combustion reaction of CO was conducted by adopting the forced oscillating reaction method and it confirmed marked acceleration in CO combustion by the Rh addition, and a low-temperature CO oxidation at a temperature range of 100±50°C could be achieved. The reason of the results is ascribed to the oxygen spillover effect induced by the existence of Rh.