Laser Synthesis in Liquid Induced Lattice Distortion in PtFeSn/Activated Carbon for Enhanced Methylcyclohexane Dehydrogenation.

Abstract

Methylcyclohexane (MCH) has emerged as one of the most promising liquid organic hydrogen carriers (LOHCs) for H₂ storage and long-distance transportation. Developing efficient, selective, and stable catalysts for MCH dehydrogenation is essential to make the process viable for practical applications. In this study, a platinum-iron-tin alloy supported on activated carbon (PtFeSn/AC) is reported, prepared via laser synthesis in liquid (LSL), exhibiting excellent dehydrogenation performance. The rapid crystallization and quenching inherent to the LSL process kinetically trap lattice distortions in the PtFeSn/AC catalyst due to atomic radius mismatches among Pt, Fe, and Sn. These distortions generate strain effects that create a local unsaturated coordination environment and downshift the d-band center of the catalyst, thereby enhancing the exposure of active sites and facilitating the desorption of toluene (TOL). As a result, the PtFeSn/AC catalyst demonstrates exceptional dehydrogenation performance, achieving a hydrogen evolution rate of 2625 mmol g_Pt ^-1 min^-1 under a weight hourly space velocity (WHSV) of 27.7 h^-1. Notably, the catalyst exhibits remarkable stability, with only a 3.2% drop in conversion after 193 h of continuous reaction. Additionally, TOL selectivity remains extraordinarily high at 99.96%. This work provides critical insights into the design of high-performance catalysts via non-conventional synthesis methods for practical applications.