The most common uranium salt is uranyl nitrate hexahydrate UO2(NO3)2·6H2O. In this study a series of uranium oxides were obtain- ed through thermal decomposition of the salt in static air at the range of 300–800 °C. The obtained uranium oxides were denoted as UO3-T, in which T expresses the calcination temperature of uranium salt.
Gold catalysts supported on UO3–T were prepared by the impregna- tion method as the following procedures [27,28]. The solid UO3–T was first impregnated with a basic solution of HAuCl4 overnight at room temperature. The pH value of the solution was controlled to be 7–8 with a 2 mol/L NaOH solution. The obtained wet sample was immersed in 6 mol/L NH3·H2O solution and thereafter washed with distilled water several times to remove residual chloride ions on the surface. After dried in a vacuum at 80 °C for 12 h, the sample was calcined in air at 300 °C for 3 h. For each sample, the theoretic Au loading is 1.0 wt.% and the actual loading was determined by atomic absorption spectroscopy to be 0.98 wt.%.