~ APPL I ED CATALYS I S A: GENERAL ELSEVIER Applied Catalysis A: General 145 (1996) 185- 193 Structure/activity relationships in coprecipitated nickel-alumina catalysts using CO 2 adsorption and methanation A. Erhan Aksoylu a A. Nilgiin Akin a Z. hsen ()nsan a David L. Trimm b,, a Department of Chemical Engineering, Bo~azi(i University, 80815 Bebek, lstanbul, Turkey b School of Chemical Engineering and Industrial Chemistry, University of New South Wales, P.O. Box 1, Kensington, NSW 2033, Australia Received 28 December 1995; revised 3 April 1996; accepted 5 April 1996 Abstract A series of coprecipitated Ni/A1203 catalysts containing 0-25 wt.-% Ni were examined for total surface area, total pore volume, metal surface area, CO 2 adsorption and CO 2 methanation activity in order to study the relation between metal content, structure and catalyst activity. Coprecipitated Ni/A1203 catalysts are found to be efficient promoters for methanation. Methana- tion activity is dependent on the nickel content and the degree of CO 2 adsorption at the reaction considered. Although A1203 does not exhibit methanation activity, it is found to be active for CO 2 adsorption. Reverse spillover increases methane production per unit nickel surface particularly for catalysts with low Ni loadings. Keywords: Nickel/alumina; Coprecipitated nickel/alumina; Carbon dioxide adsorption; Carbon dioxide methanation 1. Introduction The commercial preparation of catalysts is a balance between optimization of catalyst properties and process economics [1]. Coprecipitation, impregnation and spray drying are important options. Of these, most academic study has been focused on impregnation [2]. * Corresponding author. Tel.: ( + 61-2) 385 43 40; fax: ( + 61-2) 313 71 91; e-mail: d.trimm@ unsw.edu.au. 0926-860X/96/$15.00 Copyright © 1996 Elsevier Science B.V. All rights reserved. PII S0926-860X(96)00143-3