Study on hydrodesulfurization of thiophene over Mo/Al2O3 catalyst presulfided by thiosulfate ammonium

Ammonium thiosulfate as a novel sulfiding agent was used for presulfidation of hydrodesulfurization (HDS) catalysts. The presulfided Mo/Al2O3 catalysts with different molar ratios of S/Mo were prepared by impregnating Mo/Al2O3 catalysts with an aqueous solution of ammonium thiosulfate, followed by drying. Their characteristics of crystal phases, activation, and surface compositions were examined by X-ray diffraction, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The S2− and S6+ in ammonium thiosulfate play different roles during the activation of presulfided catalysts. The S2− sulfides Mo and S6+ reacts with Al2O3 support, decreasing the interaction of support with the active metal. The collaboration between S2− and S6+ ions improves the sulfidation of MoO3. The best HDS performance was observed for the presulfided catalyst with S/Mo = 3. Its thiophene HDS activity is 17% higher than that of Mo/Al2O3 catalyst sulfided with H2S.