Influence of reduction temperature on properties for pre-reforming of liquefied petroleum gas over mesoporous γ-alumina supported Ni–MgO catalyst by one-pot template-free route

Abstract

Mesoporous γ-alumina supported Ni–Mg oxides (NiO–MgO/γ-MA) with narrow pore size distributions were prepared via one-pot template-free route for pre-reforming of liquefied petroleum gas (LPG). Influences of reduction temperature on catalyst structures and surface properties, reduction degree of Ni2+, surface areas and sizes of Ni particles formed, and catalytic properties were systematically investigated. After reduction, mesoporous γ-MA structure was still retained and Ni nanoparticles were homogeneously distributed in support framework. The Ni particle sizes decreased with reduction temperature and exhibited a minimum at 600 °C, due to Ni crystallite growth by Ostwald ripening. The results revealed that the reduction temperatures strongly influenced reduction degree of Ni2+ species and Ni crystallite sizes, resulting in the variations in activity, stability and resistance to coke deposition of Ni–MgO/γ-MA catalysts. NiO species unreduced at lower reduction temperature not only benefited hydrocracking of LPG, but also promoted coke deposition over Ni–MgO/γ-MA catalysts.