Title : Single-atom NiMo catalyst supported on amorphous alumina for enhanced hydrodesulfurization of dibenzothiophene
Abstract:
Single-atom Catalysts (SACs) have emerged as an advanced class of heterogeneous catalysts due to their ability to maximize metal atom utilization by anchoring isolated active sites onto support materials, thereby enhancing catalytic efficiency and selectivity. In this study, a single-atom NiMo catalyst supported on amorphous alumina was developed and evaluated for the hydrodesulfurization (HDS) of dibenzothiophene (DBT), a representative sulfur-containing compound commonly used to assess desulfurization performance. The catalyst was synthesized using oleic acid and oleylamine as capping agents to achieve controlled dispersion and stabilization of active metal species, followed by sulfidation using dimethyl disulfide (DMDS) to generate the active sulfided phase. Nickel and molybdenum were selected due to their well-established synergistic interaction in HDS reactions. The optimized catalyst composition corresponded to a molar ratio of Ni/(Ni+Mo) = 0.31, which exhibited enhanced catalytic activity toward DBT conversion. Catalyst characterization was performed using Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), and Temperature-Programmed Reduction (TPR) to investigate the structural, morphological, surface, and reducibility characteristics of the catalyst. Catalytic evaluation indicated the coexistence of two dominant reaction pathways, namely direct desulfurization (DDS) and hydrogenation (HYD), during DBT conversion, while the active NiMoS phase retained its structural characteristics across compositions. Compared with catalysts prepared through conventional metal impregnation methods, the developed SAC demonstrated superior hydrodesulfurization performance, attributed to improved atomic dispersion, enhanced accessibility of active sites, and optimized Ni–Mo synergy. These findings highlight the potential of NiMo single-atom catalysts supported on amorphous alumina as an effective strategy for achieving efficient hydrodesulfurization and advancing cleaner fuel technologies.
