In situ synthesis of mesoporous NiS2-MoS2 sphere-flower hybrid for hydrodesulfurization of thiophene and 4,6-dimethyl-dibenzothiophene

A series of new NiS 2 -MoS 2 - x ( x  = 0–0.5) sphere-flower hybrids with different Ni/Mo molar ratios, synthesized via a one-pot hydrothermal method, were used as catalysts for hydrodesulfurization (HDS) of thiophene (TP) and 4,6-dimethyl-dibenzothiophene (4,6-DMDBT). The characterizations show that the microstructure of MoS 2 , including the size of MoS 2 nano-flowers, the length of MoS 2 slabs, and the number of defects, was regulated by changing Ni/Mo ratios. Increasing the Ni/Mo ratio in the NiS 2 -MoS 2 - x catalysts significantly boosts their HDS activity, with the optimum ratio being 0.2. In addition, the NiS 2 -MoS 2 -0.2 catalyst exhibits the best direct desulfurization performance, which is associated with the minimum ratio of average slab length ( L av ) to average stacking number ( N av ) as well as the highest concentration of Ni-promoted Mo sites and sulfur vacancies. Moreover, Ni-containing NiS 2 -MoS 2 - x catalysts, characterized by a highly stable sphere-flower configuration, exhibit superior structural stability and catalytic durability than the Ni-free NiS 2 -MoS 2 -0 catalyst.