Nanosized Au Catalysts Supported on Mg(OH)2-CeO2 for Preferential Oxidation of CO in Hydrogen Stream

Abstract

Preferential oxidation of carbon monoxide in the presence of hydrogen (PROX) is a promising method to remove CO from a hydrogen-containing gas mixture. Nanosized gold catalyst supported on CeO2 and modified with Mg(OH)2 was used for preferential oxidation of carbon monoxide in hydrogen-rich stream in this study. Mg(OH)2 was added on CeO2 by incipient-wetness impregnation. Au was loaded on Mg(OH)2-CeO2 by deposition-precipitation method. PROX reaction was carried out in a continuous flow, fixed bed reactor. CO/O2 feed ratio was fixed at 1 to magnify the difference of various catalysts. The catalysts were characterized by N2 sorption, TEM, HR-TEM and XPS. Mg(OH)2 formed a thin layer on the surface of CeO2. CeO2 was in the crystalline phase and Mg(OH)2 was amorphous. Au particles were homogeneously dispersed on the support with a size of 2 - 5 nm. Using CeO2 as a support could increase the dispersion of Mg(OH)2 and thus increase the interaction between Au and Mg(OH)2. Adding Mg(OH)2 on Au/CeO2 could suppress H2 oxidation and therefore increase CO oxidation activity.