Hierarchical Interconnected NiMoN with Large Specific Surface Area and High Mechanical Strength for Efficient and Stable Alkaline Water/Seawater Hydrogen Evolution

Highlights A hierarchical interconnected NiMoN (HW-NiMoN-2h) was successfully prepared based on a rational combination of hydrothermal and water bath processes. HW-NiMoN-2h exhibited high hydrogen evolution reaction (HER) activity due to its large specific surface area and good stability due to its enhanced mechanical strength. In 1 M KOH seawater, HW-NiMoN-2h delivered current density of 1 A cm −2 for HER at an overpotential of 130 mV and showed excellent stability over 70 h at 1 A cm −2 .