Influence of calcination temperature on textural and structural properties, reducibility, and catalytic behavior of mesoporous gamma-alumina-supported Ni-Mg oxides by one-pot template-free route

摘要

gamma-Alumina-supported Ni-Mg oxides by one-pot route were calcined in the range of 300-700 degrees C. Influences of calcination temperature on catalyst structure, surface properties, interaction between metal oxides and support, reducibility of Ni2+ ions, and Ni particle dispersion were systematically investigated. The catalysts showed wormhole-like mesoporous structures with narrow pore size distributions. NiO species were homogeneously distributed with the strengthened interaction by support with calcination temperature, producing uniform Ni nanoparticles throughout gamma-alumina frameworks after reduction. The Ni particle sizes increased with calcination temperature due to Ni crystallite growth by Ostwald ripening rather than migration of Ni nanoparticles. The investigation for steam reforming of liquefied petroleum gas revealed that smaller Ni nanoparticles facilitated hydrocarbon reforming, methanation of carbon oxides, and water-gas shift and lowered the rate of coke deposition; mesopores with uniform sizes were favorable for diffusion of reactants and products to active sites, improving catalytic activity and stability. (C) 2015 Elsevier Inc. All rights reserved.