Epitaxial synthesis of Ni-MoS/TiCT MXene heterostructures for hydrodesulfurization.

Hierarchical structures of 2D layered TiCT MXene hold potential for a range of applications. In this study, catalysts comprising few-layered MoS with TiCT have been formulated for hydrodesulfurization (HDS). The support TiCT was derived from MAX phases (TiAlC) a liquid-phase exfoliation process, while MoS was obtained from synthesized aqueous ammonium tetrathiomolybdate (ATM). Furthermore, a series of catalysts with different architectures was synthesized by confinement of ATM and/or the promoter Ni in TiCT at different mole ratios, through a thermal conversion process. The synthesized MoS/TiCT and Ni-MoS/TiCT catalysts were characterized using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), high-resolution transmission electron microscopy (HRTEM), and temperature-programmed reduction (TPR) measurements. The number of MoS layers formed on the TiCT support was calculated using Raman spectroscopy. The heterostructured few-layered MoS/TiCT catalysts were applied in sulfur removal efficiency experiments involving thiophene. The active MoS sites confined by the TiCT enhanced hydrogen activation by proton saturation, and the electron charge stabilized the sulfur atom to facilitate hydrogenation reactions, leading to predominant formation of C hydrocarbons. The Ni-MoS/TiCT showed the best activity at a promoter molar ratio of 0.3 when compared to the other catalysts. In particular, it is evident from the results that ATM and TiCT are potential materials for the fabrication of hierarchical few-layered MoS/TiCT catalysts for enhancing hydrodesulfurization activity in clean fuel production.