Synergistic reaction kinetics of Pt single atoms/MoS2 and nanoparticles for energy-saving hydrogen production assisted by green electrosynthesis of azotetrazolate compound

Abstract

Overall water splitting (OWS) involves two important half-reactions, namely hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). However, due to the high theoretical overpotential of OER, OWS needs to be realized with high energy consumption. Using anodic oxidation reaction with lower theoretical potential to replace oxygen evolution reaction (OER) can effectively reduce the energy consumption of overall water splitting (OWS) for hydrogen production. Here, we introduce a new oxidation reaction of green electrosynthesis of energetic materials (EMs) and coupled with OWS. The catalyst was prepared by electrodepositing Pt nanoparticles (Pt NPs) and Pt single atoms (Pt SAs) on MoS2 nanosheets, which drives highly-efficient hydrogen production of 35.6 mV to drive 10 mA cm−2. DFT calculations reveal the synergistic mechanism of Pt NPs and Pt SA/MoS2 substrate for promoting hydrogen production, is that the energy barrier of water dissociation was reduced on the Pt NC sites and the produced H* migrated to the adjacent S sites for Heyrovsky step, while the Pt SA sites served as electron regulator for more thermoneutral H* adsorption on S sites, realizing the synergistic reaction kinetics in MoS2/Pt for promoting alkaline HER. Importantly, by integrating the OWS and electrosynthesis of 5,5′-azotetrazole (ZT) EMs, the cell voltage can be significantly reduced to 1.29 V at 10 mA cm−2, realizing low-energy-consumption for hydrogen production. Meanwhile, the green electrosynthesis of ZT is achieved to avoid the hazardous process of traditional preparation methods. This study presents a new strategy for green electrosynthesis of EMs and low-energy-consumption hydrogen production.