Preparation of Co-Al mixed oxide-supported gold catalysts and their catalytic activity for N2O decomposition

Au/Co-Al catalysts were prepared by using the ion-exchange and coprecipitation methods, and their activities for the catalytic decomposition of N2O were tested. BET, XRD, and H2-TPR techniques were used to characterize the catalysts. The results show that the activity of Au/Co-Al catalyst prepared by using ion-exchange method is higher than that using coprecipitation method. For the catalysts prepared by ion-exchange method, the effects of preparation parameters, such as Au loading, pretreatment of HAuCl4 solution, and calcination temperature, upon N2O conversion were investigated. The optimal preparation parameters of Au/Co-Al catalysts are 1.1% of Au loading, HAuCl4 solution adjusted to pH 9, and 300°C of calcination temperature. It is indicated that the addition of Na species in Co-Al mixed oxide promoted the reduction of Co3+ to Co2+ and enhanced the catalytic activity for N2O decomposition.