Cyclic molecular designed dispersion (CMDD) of Fe2O3 on CeO2 promoted by Au for preferential CO oxidation in hydrogen

Abstract

A novel cyclic molecular designed dispersion (CMDD) method was employed to uniformly deposit 0.0–6.5 wt% Fe on CeO2. The gold catalysts (0.0–3.8 wt%) supported on Fe2O3-CeO2 were tested for CO preferential oxidation (PROX). As the CMDD method involved grafting of Fe (acac)3 onto the surface –OH groups, 2.7 surface –OH/nm2 was determined for the CeO2 by using the Grignard reagent. The performance of CMDD catalysts was compared with the corresponding catalysts prepared by impregnation. The catalysts were characterized by XPS, XRD, TPR, HRTEM-EDX, BET and ICP. The results suggested that Au/Fe2O3-CeO2 was significantly more active and selective than Au/CeO2. The CMDD-prepared catalysts with 1.4–2.5 wt% iron showed the highest activity and selectivity, especially at temperatures as low as 323 K. The formation of Ce-Fe solid solution for CMDD catalysts promoted the dispersion of both iron and gold. Highly dispersed gold nanoparticles mainly as small as 2.2 nm were observed in HRTEM.