Enhanced Cooperative Generalized Compressive Strain and Electronic Structure Engineering in W-NiN for Efficient Hydrazine Oxidation Facilitating H Production.

As promising bifunctional electrocatalysts, transition metal nitrides are expected to achieve an efficient hydrazine oxidation reaction (HzOR) by fine-tuning electronic structure via strain engineering, thereby facilitating hydrogen production. However, understanding the correlation between strain-induced atomic microenvironments and reactivity remains challenging. Herein, a generalized compressive strained W-NiN catalyst is developed to create a surface with enriched electronic states that optimize intermediate binding and activate both water and NH. Multi-dimensional characterizations reveal a nearly linear correlation between the hydrogen evolution reaction (HER) activity and the d-band center of W-NiN under strain state. Theoretically, compressive strain enhances the electron transfer capability at the surface, increasing donation into antibonding orbitals of adsorbed species, which accelerates the HER and HzOR. Leveraging both compressive strain and the modified electronic structure from W incorporation, the W-NiN catalysts demonstrate outstanding bifunctional performance, achieving overpotentials of 46 mV for HER at 10 mA cm and 81 mV for HzOR at 100 mA cm. Furthermore, W-NiN catalyst achieves efficient overall hydrazine splitting at a low cell voltage of 0.185 V for 50 mA cm, maintaining stability for ≈450 h. This work provides new insights into the dual engineering of strain and electronic structure in the design of advanced catalysts.