Effect of preparation on Ru - Zn ultrafine catalysts in partial hydrogenation of benzene

A series of ultrafine Ru - Zn catalysts have been prepared with direct reduction and hydroxide methods with various Ru/Zn ratios. Sodium borohydride was used as a reducing agent to avoid the agglomeration problem posed by the high reduction temperature when using hydrogen as a reducing agent. The preparation method has a great effect on the composition and surface area of the catalyst. The catalysts prepared with the hydroxide method gave a lower surface area. However, it showed high activity of benzene disappearance. The performance of Ru - Zn catalysts prepared with the hydroxide method display a more distinctive behavior in benzene hydrogenation upon variation of the atomic ratio of ruthenium to zinc. The catalysts prepared with the hydroxide method were more selective to cyclohexene than those prepared with the direct reduction method. The Ru/Zn ratio also has a great influence on the selectivity to cyclohexene.