Effect of reduction temperature on the structure and hydrodesulfurization performance of Na doped Ni₂P/MCM-41 catalysts

The removal of sulfur compounds from petroleum is increasingly important because of the environmental pollution caused by sulfur compounds. In this work, Na doped Ni₂P/MCM-41 catalysts were successfully prepared, and their hydrodesulfurization (HDS) performances were assessed using dibenzothiophene (DBT) as a model molecule. Moreover, the effects of reduction temperature (450-600 °C) on the structure and HDS performance of the Ni₂P/Na-MCM-41 catalysts were studied. Results showed that: (a) the reduction temperature of the catalyst could be as low as 450 °C due to Na doping, which is about 200 °C lower than that of the conventional temperature-programmed reduction method (650-1000 °C); (b) increasing the reduction temperature lead to an increase in the diameter of Ni₂P particles, which was demonstrated by size distribution analysis; (c) the HDS performance of the Ni₂P/Na-M41-T catalysts increases with reduction temperature and 99.2% DBT conversion was observed for Ni₂P/Na-M41-600, whereas the hydrogenation route of the catalysts decreased with increasing the reduction temperature, which indicates the lower reduction temperature favored the direct desulfurization pathway (DDS).