Unveiling the Role of Intermediate Neutral Hydrogen in Bridging Moisture-Electric Generation and Hydrogen Evolution.

Abstract

Harvesting renewable energy from ambient moisture into sustainable electricity represents a promising route to address global energy and climate challenges. However, the moisture energy utilization is low in existing moisture-electric generators (MEGs) technologies. Here, we report a carrier-type-engineered graphene oxide (GO)-based MEG that not only generates electricity from moisture but also drives clean hydrogen production via electrochemical water splitting. The optimized device delivers a steady voltage output of 0.90 V and an ultra-high current density of 0.25 mA∙cm^-2 at 80% relative humidity, maintaining excellent stability for two weeks. Importantly, we first reveal that the proton-electron recombination during MEG discharge produces abundant neutral hydrogen atoms absorbed on the carbon nanotube substrate, which subsequently act as highly active species for the hydrogen evolution reaction (HER), achieving a remarkably low overpotential of ∼20 mV. The present work marks the first demonstration of hydrogen generation directly coupled with MEG discharge via cascade utilization of intermediate neutral hydrogen molecules. Furthermore, the device can be rejuvenated through a recycling treatment, enabling cyclic operation. This study not only advances the fundamental understanding of charge transfer and proton dynamics in MEGs but also introduces a new paradigm for coupling ambient-energy harvesting with sustainable hydrogen production.