Interfacial hydrogen evolution reaction from Ouzo-effect-generated bulk nano/micro droplets of liquid organic hydrogen carriers

Hypothesis: Organosilanes as liquid organic hydrogen carriers (LOHCs) offer a promising solution for the safe storage and transport of hydrogen gas as a clean energy source. However, the dehydrogenation reaction of organosilanes in the presence of water faces the challenge of sluggish kinetics in conventional bulk reactions. Dispersing organosilanes as stable nanodroplets in basic water offers a potential strategy to increase the interfacial area, thereby enhancing H₂ production efficiency. Experiments: Organosilane nanodroplets were generated through spontaneous emulsification via the Ouzo effect in a ternary organosilane-water-acetone system. The reaction between the organosilane nano/microdroplets and the alkaline aqueous phase led to H₂ generation. This study investigates how the composition and size distribution of these droplets influence H₂ production yield. To gain deeper insight into the reaction mechanisms, single reacting microdroplets were analyzed using side-view imaging and confocal microscopy. Findings: Organosilane nano/microdroplets formed from the Ouzo effect in the presence of a co-solvent. H₂ formation yields from interfacial reactions of these droplets reached up to 25%, whereas single reacting microdroplets achieved a maximum yield of 3.5%. This study demonstrates that spontaneous emulsification in ternary mixture using the Ouzo effect can enhance reaction kinetics and product yields. Furthermore, detailed insights into the behavior of H₂ bubbles, from their nucleation within a microdroplet to their growth and eventual detachment, were obtained through the analysis of single reacting microdroplets.