HYDROGEN PRODUCTION BY LOW TEMPERATURE METHANE STEAM REFORMING USING Ag AND Au MODIFIED ALUMINA SUPPORTED NICKEL CATALYSTS

摘要

Au (1%) and Ag (1%) modified Ni (8%) catalysts deposited on γ-alumina were prepared by co-impregnation method. The catalysts structure was investigated by N_2 adsorption - desorption, XRD and XPS techniques revealing the presence of Au and Ag on the catalyst's surface and their interaction with nickel and alumina. The catalysts were tested in methane steam reforming reaction for hydrogen production in a fixed bed flow reactor, at temperature ranged from 450℃ to 700℃ and CH_4/H_2O ratio of 1/4. At low reaction temperatures (T<600℃) the addition of Au improves the catalytic activity and stability of Ni catalyst. The addition of Ag decreases the catalytic properties of Ni/Al_2O_3. At high temperatures the gold influence is not so important, and the catalysts deactivate.