Three-dimensional porous Pt/N-MXene catalyst for dehydrogenation of a liquid organic hydrogen carrier

A novel synthetic strategy is proposed to create high zero-valent platinum (Pt) components, sub-nanometer Pt clusters, and three-dimensional (3D) Pt/ nitrogen-doped MXene (N-Ti 3 C 2 T x ) catalyst through electrostatic self-assembly combined with non-in-situ doping pyrolysis. Compared with the primary Pt/Ti 3 C 2 T x , the N-doped Pt/N-Ti 3 C 2 T x , which has a 3D wrinkled porous structure, increases the residence time of methylcyclohexane (MCH) on the catalyst surface during gas–solid reactions and improves the mass transfer efficiency of MCH. In addition, the N-doped Pt/N-Ti 3 C 2 T x , which optimizes the electronic coordination environment, produces sub-nanometer Pt clusters, in which Pt mainly exists as Pt (0) (80.78 %) and avoids the presence of low catalytic activity Pt (IV). The Pt 0.5% /N-MXene catalyst exhibits significant catalytic performance in the dehydrogenation of MCH in a fixed-bed reactor, with a hydrogen evolution rate of 636.30 mmol·g Pt -1 ·min - 1 , which significantly surpasses 176.60 mmol·g Pt -1 ·min - 1 for N-undoped Pt 1% /MXene and 78.13 mmol·g Pt -1 ·min - 1 for commercial Pt 1% /TiO 2 . Density functional theory calculations, Pt/N-Ti 3 C 2 T x exhibits lower Pt electronic states and has a d -band center closer to the Fermi level than Pt/Ti 3 C 2 T x . This configuration leads to the stronger MCH adsorption on the Pt sites of Pt/N-Ti 3 C 2 T x , promoting faster H 2 generation and release, thereby achieving a higher catalytic activity.