Effect of thermal treatment on morphology and catalytic performance of NiW/Al2O3 catalysts prepared using citric acid as chelating agent

摘要

In the present work, NiW/Al2O3 catalyst was prepared with the use of citric acid and thermally treated at temperatures of 120, 220, 300 and 450 degrees C. It was shown that the thermal treatment at temperatures of 220-300 degrees C leads to decomposition of citrate ligands, 450 degrees C-to the almost complete removal of organic carbon. HRTEM of the sulfided catalysts showed that stacking number of WS2 increases with the increase of the thermal treatment temperature while the WS2 slab length has minimum at 220 degrees C. The results of XPS indicated that the sulfidation degree of tungsten and nickel decreases with the increase of the thermal treatment temperature.