Highly active subnano Rh/Fe(OH)x catalyst for preferential oxidation of CO in H2-rich stream

A novel catalyst formulation of 3.1 wt.% Rh/Fe(OH)(x) was prepared via a co-precipitation method and investigated for CO preferential oxidation in H-2-rich stream. This catalyst exhibited a wider temperature range of 20-70 degrees C for CO total removal and better resistance to CO2 and H2O compared with the standard gold catalyst, standing out as the best Rh-based catalyst ever. The Rh species were highly dispersed in a subnano scale of similar to 1 nm and improved the reducibility of Fe(OH)(x) support. The adsorption of o(2) was thus promoted over the reduced support, together with the weakened CO adsorption over the Rh clusters, permitting a non-competitive Langmuir-Hinshelwood mechanism through the elementary reaction of CO(ad) + O-(ad). The reaction rate equation of r= k[CO](0.73)[O-2](0.64) and small apparent activation energy of 24 kJ mol(-1) were then derived from the kinetic studies. (C) 2015 Elsevier B.V. All rights reserved.