Efficient Hydrogen Production from Aqueous Methanol Driven by Microdroplet Interfaces.

Methanol is an attractive liquid feedstock for sustainable H2 production due to its high hydrogen storage density and favorable handling properties, yet conventional routes typically involve harsh conditions or noble-metal catalysts. Here, we present a catalyst-free microdroplet strategy for efficient H2 production from aqueous methanol under mild conditions, achieving an evolution rate of 968.1 μmol h-1 in an enlarged 3.5 L reactor using seawater as the water source. This performance outperforms most reported photocatalytic methanol dehydrogenation systems, with formaldehyde as the dominant liquid-phase product. Mechanistic insights from electron paramagnetic resonance, isotopic labeling, mass spectrometry, and theoretical calculations provide a plausible explanation for methanol dehydrogenation in water microdroplets, driven by hydroxyl radicals (•OH) generated at the gas-liquid interface. This approach was successfully validated in both scaled-up experiments and in additional hydrogen storage media (formaldehyde, ammonia, ethylene glycol, formic acid, and ethanol), suggesting its potential scalability and substrate generality for an H2 production platform.