Adsorption Behavior of Au(III) Complex Ion on Nickel Carbonate and Nickel Hydroxide

When preparing gold(Au) supported on NiO catalysts by the coprecipitation method, the chemical state of the coprecipitated Au differed when Na2CO3 and NaOH were used as the coprecipitating reagents. In this preparation using Na2CO3 and NaOH solutions, precursor of support metal was largely NiCO3 and Ni(OH)2, respectively. Therefore, the different chemical states of Au may be controlled by the interaction between the [Au(OH)4]− and precursor of support metal. The aim of this study is to elucidate why the chemical state of Au differs when using NiCO3 and Ni(OH)2.