HE CATALYTIC activities of CaCO 3 -, TiO 2 -, Al 2 O 3 -and SiO 2 -..... supported Ni catalysts in reduction of p-nitrophenol to paminophenol were investigated. The catalysts were prepared by impregnation using a solution of appropriate concentrations of NiCl 2 in order to obtain catalysts with 2.5, 5 and 10% nickel. The dried solids were treated with hydrazine hydrate to reduce nickel ions to metallic nickel, on which the reduction of p-nitrophenol takes place. The catalysts were characterized

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... by XRD and SEM before and after conducting the reduction reaction of p-nitrophenol .The results showed that all catalysts contain crystalline nano nickel. The catalysts were active in reduction of p-nitrophenol into p-aminophenol. The activity was in the following order: Ni/ TiO 2 > Ni/ CaCO 3 > Ni/ SiO 2 > Ni/ Al 2 O 3 , i.e. the activity was decreased with increasing the acidity of the supports.