Constructing of <i>n</i>‐Type Semiconductor Heterostructures for Efficient Hydrazine‐Assisted Hydrogen Production

Abstract Hydrazine‐assisted water electrolysis presents a promising approach toward energy‐efficient hydrogen production. However, the progress of this technology is hindered by the limited availability of affordable, efficient, and durable catalysts. In this study, a feasible strategy is proposed for interface modulation that enables efficient hydrogen evolution and hydrazine oxidation through the construction of n ‐type semiconductor heterostructures. The metal–semiconductor contacts are rationally designed using ruthenium nanoclusters and a range of metal oxide (M–O) semiconductor heterostructures, including p ‐type semiconductor substrates (NiO, Co 3 O 4 , NiCo 2 O 4 , CuCo 2 O 4 , ZnCo 2 O 4 ) and n ‐type semiconductor substrate (Fe 2 O 3 ). Intriguingly, Ru nanoclusters supported on p ‐type M–O substrates induce a transition from p ‐type M–O to n ‐type M‐O/Ru. The design of n ‐type semiconductor heterostructures can significantly reduce space‐charge regions and increase charge carrier concentration, thereby improving the electrical conductivity of electrocatalysts. Moreover, Ru atoms can serve as highly efficient active sites for hydrogen evolution reaction and hydrazine oxidation reaction. The NiO/Ru heterostructure can drive current densities of 10 and 100 mA cm −2 with only 0.021 and 0.22 V cell voltages for hydrazine‐assisted water electrolysis. This work provides new insights for the development of highly efficient semiconductor catalysts, enabling energy‐saving hydrogen production.