Progress in hydrazine oxidation-assisted hydrogen production

Hydrogen production via electrochemical water splitting demands high working voltages (>1.23 V) and hence incurs high electricity costs, encumbering its large-scale applications. The development of more high-efficiency and electricity-saving systems for hydrogen production is of great significance. Hydrazine oxidation reaction (HzOR)-assisted hydrogen production technology, which is constructed by replacing the anodic oxygen evolution reaction in pure water electrolysis systems with the HzOR, can greatly reduce the working voltage and electricity consumption, and hence shows great application prospects. In recent years, numerous studies have focused on designing various bifunctional electrocatalysts to simultaneously catalyze the cathodic and anodic reactions in HzOR-assisted hydrogen production systems. However, comprehensive reviews summarizing and commenting on this field are scarce. This review provides a systematic and insightful overview of the developments in HzOR-assisted hydrogen production technology from 2017 to the present, primarily focusing on catalyst design strategies, catalytic mechanisms, and economic and application analysis. Additionally, this review discusses several challenges and outlines future research directions in this field to attract more researchers' attention and accelerate the research and potential applications of HzOR-assisted hydrogen production technology.