Epitaxial synthesis of Ni–MoS(2)/Ti(3)C(2)T(x) MXene heterostructures for hydrodesulfurization

Hierarchical structures of 2D layered Ti(3)C(2)T(x) MXene hold potential for a range of applications. In this study, catalysts comprising few-layered MoS(2) with Ti(3)C(2)T(x) have been formulated for hydrodesulfurization (HDS). The support Ti(3)C(2)T(x) was derived from MAX phases (Ti(3)AlC(2)) via a liquid-phase exfoliation process, while MoS(2) 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 Ti(3)C(2)T(x) at different mole ratios, through a thermal conversion process. The synthesized MoS(2)/Ti(3)C(2)T(x) and Ni–MoS(2)/Ti(3)C(2)T(x) 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(2) layers formed on the Ti(3)C(2)T(x) support was calculated using Raman spectroscopy. The heterostructured few-layered MoS(2)/Ti(3)C(2)T(x) catalysts were applied in sulfur removal efficiency experiments involving thiophene. The active MoS(2) sites confined by the Ti(3)C(2)T(x) enhanced hydrogen activation by proton saturation, and the electron charge stabilized the sulfur atom to facilitate hydrogenation reactions, leading to predominant formation of C(4) hydrocarbons. The Ni–MoS(2)/Ti(3)C(2)T(x) 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 Ti(3)C(2)T(x) are potential materials for the in situ fabrication of hierarchical few-layered MoS(2)/Ti(3)C(2)T(x) catalysts for enhancing hydrodesulfurization activity in clean fuel production.