Effect of chalcogen (S, Se and Te) surface additives on the dehydrogenation of a liquid organic hydrogen carrier system, octahydroindole–indole, on a Pt (1 1 1) surface

Abstract

Liquid organic hydrogen carrier (LOHC) systems have gained serious traction of late due to their potential application in the envisaged hydrogen economy. This is mainly because LOHCs can undergo reversible dehydrogenation in the presence of a catalyst. Using density functional theory calculations with van der Waals corrections, the role of chalcogens (S, Se and Te) as surface additives, in boosting the catalytic activity of Pt (111) surface, was investigated for the dehydrogenation of the LOHC system, octahydroindole to indole. The calculated adsorption energies indicate that octahydroindole (the hydrogen rich form (LOHC+)) and indole (the hydrogen lean form (LOHC−)) stably adsorbs on the Pt (111) surface(s) in the presence of chalcogen surface additives. The S and Se atoms were found to be better catalytic activity boosters in lowering the calculated reaction energy for dehydrogenating octahydroindole to indole than the Te atom. For all the considered chalcogen surface additive species, the calculated reaction energies indicate that the dehydrogenation of octahydroindole to indole can proceed either with or without indoline as a reaction intermediate.