Plasma assisted preparation of highly active NiAl2O4 catalysts for propane steam reforming

In this study, Ni–Al spinel catalyst prepared with glycine-nitrate combustion method and treated by DBD plasma in different atmospheres have been investigated for propane steam reforming (PSR). It is revealed by H2-TPR that compared with traditional calcination method, NiO/Ni particles have much stronger interaction with the supports on the plasma-treated Ni–Al spinel catalysts. Therefore, catalysts with smaller NiO/Ni grains sizes, higher metallic Ni active surface areas can be achieved, as evidenced by XRD and H2 adsorption-desorption measurements. NH3-TPD results demonstrate that the plasma treatment led to a decrease of the acidity of the Ni–Al spinel catalyst. Furthermore, larger quantities of surface active oxygen sites are also formed after plasma treatment, as testified by the O2-TPD and XPS results. As a consequence, the plasma-treated catalysts show significantly improved catalytic activities and coke resistance. Plasma treatment in H2/Ar atmosphere after calcination process is considered to be the best route to prepare NiAl2O4 catalysts, which could be employed to obtain PSR catalysts with the highest catalytic activity and best anti-coking performance. It is believed that the higher metallic Ni active surface area and much more surface active oxygen sites induced by plasma treatment are the inherent reasons accounting for the enhanced catalytic performance of the Ni–Al spinel catalysts.