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.