Mechanochemical synthesis of Pt/TiO2 for enhanced stability in dehydrogenation of methylcyclohexane

Abstract

Catalytic hydrogenation/dehydrogenation of liquid organic hydrogen carriers (LOHCs), such as methylcyclohexane (MCH), enables versatile and safe transport and storage of hydrogen as a carbon neutral fuel. Supported platinum catalysts are commonly used for the dehydrogenation reaction, however, they often suffer from loss of activity due to coking. Herein, we present mechanochemically synthesised platinum on titania catalyst for the dehydrogenation of MCH, prepared starting only from metallic platinum and titania. Dry mechanochemical catalyst syntheses do not produce waste waters or toxic fumes, which are generated in the deposition of metal precursors by conventional wet synthesis methods. Detailed characterisation of the catalysts revealed that ball milling produced highly dispersed nanoparticles. Furthermore, continuous-flow MCH dehydrogenation experiments showed that the mechanochemically prepared Pt catalyst exhibited improved selectivity and stability compared to a conventional impregnated Pt/TiO₂ catalyst. The hydrogen production rate of the novel ball-milled catalyst was among the highest reported for dehydrogenation of methylcyclohexane, 670 mmol_H2 g_Pt⁻¹ min⁻¹.