Propane steam reforming on mesoporous NiO–MgO–SiO2 catalysts for syngas production: Effect of the MgO/SiO2 molar ratio

Abstract

In this research, a series of NiO-xMgO-SiO2 catalysts with various MgO/SiO2 molar ratios were prepared via precipitation method followed by a hydrothermal treatment in the presence of PVP as surfactant. The synergic effect between MgO and SiO2 leading to the various characteristic and catalytic performance during propane steam reforming was investigated in detail. The results showed that 15 wt% NiO-0.5MgO–SiO2 catalyst possessed the highest catalytic activity (68.9% conversion for C3H8 at 550 °C) with a negligible amount of carbon formation after 20 h of reaction duration. This superior catalytic performance can be attributed to the enhanced basicity strength along with strong metal-support interaction due to the formation of NiO–MgO solid solution, as confirmed by CO2-TPD and TPR analyses, respectively. In addition, the maximum hydrogen yield was obtained through the NiO–MgO sample because of higher progress in other hydrogen production routes as opposed to that of the propane steam reforming. It also can be suggested that relatively weak interaction between active sites and support was probably the main reason for unstable catalytic behavior of NiO–SiO2 sample with the lowest activity. This study confirms that the appropriate MgO/SiO2 ratio led to the sufficient metal-support interaction and delicate balance between acidic/basic sites, which was followed by the great activity, and coke resistance during PSR.