Preparation of mesoporous nanostructure NiO–MgO–SiO2 catalysts for syngas production via propane steam reforming

Abstract

In this research, the propane steam reforming (PSR) as a promising alternative route over a mesoporous NiO–MgO–SiO2 catalyst to produce syngas (SG) was undertaken. This catalyst was prepared using a co-precipitation method followed by hydrothermal treatment. The influence of such catalyst preparation factors as the hydrothermal time and temperature, pH and calcination temperature on the physicochemical characteristics of the prepared samples were examined. Next, these materials were characterized through the BET-BJH, XRD, TPR, and FTIR analyses. The thermal stability of this catalyst was tested through the TGA and DTA techniques. Furthermore, the deactivation of the calcined catalysts at different temperatures was investigated via the TPO analysis. The utilized synthesis method led to preparation of a species with a mesoporous structure possessing a rather high surface area of 741 m2g-1. The catalyst performance at a reaction temperature of 550 °C revealed that, the increment in calcination temperature from 500 to 800 °C led to lowering of the propane conversion as well as the hydrogen yield from 65 to 37.4% and 39.4 to 22.6%, respectively. Meanwhile, the extent of the deposited coke upon the catalyst surface was reduced when implementing the higher calcination temperature. This was attributed to high amounts of the NiO, which was included in the solid solution containing the MgO–SiO2 support. In other words, the isolation of Ni2+ with Mg2+ species and strong interaction between NiO and MgO decreased the NiO particle size hence, its reducibility. These in turn led to the formation of smaller active sites possessing higher deactivation resistance against sintering and coke deposition. Thus, a highly active and stable catalyst was developed.