Mono- and bimetallic platinum-based catalysts in dehydrogenation of perhydro dibenzyltoluene

Liquid organic hydrogen carriers (LOHCs) are emerging as solutions for storing renewable hydrogen. A particularly promising LOHC candidate system is dibenzyltoluene (DBT) and its fully hydrogenated form, perhydro dibenzyltoluene (H18-DBT). The dehydrogenation reaction of H18-DBT is critical for the feasibility of the LOHC system, requiring catalysts that are active, resistant towards deactivation, and do not promote the decomposition of the LOHC compound. This study examined the dehydrogenation of H18-DBT using both monometallic Pt-catalysts and bimetallic catalysts composed of Pt Pd, Pt Ru and Pt Re supported on alumina and titania. The extent of dehydrogenation ranged from 32% to 69% over 45 min in a batch reactor, with a molar ratio of H18-DBT to Pt of 400:1. In the series of Pt-catalysts, the highest quantity of weak acid sites and a moderate amount of medium acid sites exhibited the highest dehydrogenation activity. The bimetallic Pt Re catalyst on alumina demonstrated improved efficiency in H18-DBT dehydrogenation, though it did not outperform the most active catalyst, monometallic Pt supported on titania. Notably, the decomposition products of H18-DBT in the hydrogen gas reached concentration of 0.03 wt% within 45 min reaction time. • The weak-medium strength acid sites of Pt catalysts enhanced H18-DBT dehydrogenation. • Bimetallic Pt Re supported on alumina showed higher dehydrogenation activity than monometallic Pt on alumina. • Formation of H18-DBT decomposition products was detected in hydrogen gas.