Mesoporous and nanostructured CeO2 as supports of nano-sized gold catalysts for low-temperature water-gas shift reaction

Mesoporous particles and ID nanorods of cerium oxides have been prepared by modifying the hydrothermal route of a surfactant-assisted controllable synthesis. Mesoporous cerias were obtained in a sealed glass vessel under continuous stirring, while ceria nanorods were obtained in a Teflon-lined autoclave without stirring. The mesoporous cerias did not show long-range mesoscopic organization, exhibiting a broad mesopore size distribution in the region 8-15 nm. A BET surface area of 100 m(2)/g with a total pore volume of 0.33 cm(3)/g is obtained for as-synthesized mesoporous ceria. The ceria nanorods exhibit a cubic crystalline structure after calcination, having the lengths in the range of 150-300 nm and diameters in the range of 10-25 nm. The growth direction of ceria nanorods is along [1 1 0]. A surface area of above 50 m(2)/g is obtained in the calcined nanorods. These synthesized ceria materials were used as supports of nano-sized gold catalysts, prepared by deposition-precipitation method. Their catalytic activity was evaluated by the low-temperature water-gas shift reaction. The gold/mesoporous ceria catalytic system exhibited higher catalytic activity than gold/ceria nanorods. It is revealed that the mesoporous and nanostructured cerias are of much interest as potential supports for gold-based catalysts that are effective for low-temperature water-gas shift reaction. (c) 2007 Elsevier B.V. All rights reserved.