Influence of Pt particles size and reaction atmosphere on methylcyclohexane dehydrogenation

Methylcyclohexane (MCH) dehydrogenation for H 2 production is a promising route in liquid organic hydrogen carriers technology. However, there are few reports on the influence of Pt size on methylcyclohexane dehydrogenation under different reaction atmospheres. In this study, a series of Pt/Al 2 O 3 catalysts with Pt particle sizes ranging from 0.67 to 1.26 nm were prepared via the impregnation method. The influences of Pt particle size on MCH dehydrogenation under H 2 and N 2 atmospheres were investigated. The toluene (TOL) product adsorbed on Pt site has a significant effect on the activity and stability of Pt/Al 2 O 3 for MCH dehydrogenation. Under N 2 atmosphere, the poisoning of Pt/Al 2 O 3 by toluene leads to a low activity in this reaction. By contrast, under H 2 atmosphere, the adsorption of toluene can be effectively inhibited by H 2 , and thus an enhanced catalytic performance can be achieved. The catalyst with Pt size of 0.67 nm exhibits a high turnover frequency (TOF) of 33,530 mol H2 ·mol Pt −1 ·h −1 , corresponding to a H 2 evolution rate of 2,865 mmol·g Pt −1 ·min −1 . These findings provide a deeper understanding of the dependence of catalyst structure and reaction conditions on MCH dehydrogenation, offering fundamental guidance for the design of efficient catalysis system for MCH dehydrogenation.