Devaraj Ramasamy

Efficient electrochemical water splitting requires unobstructed electron transfer across heterogeneous catalyst–support interfaces, yet in systems such as high-entropy alloy (HEA) nanoparticles on nitrogen-activated carbon (NAC), the nanoscale electronic factors governing charge transport remain experimentally elusive. Bulk electrochemical measurements mask local variations in composition, surface potential, and morphology that modulate the work function (Φ) and thereby interfacial electron transfer [1–3].

The transition to a decarbonized global economy hinges on the production of "green" hydrogen through water electrolysis. Alkaline Water Electrolysis (AWE) is currently the most viable technology for large-scale deployment due to its reliance on earth-abundant transition metals rather than scarce platinum-group metals. However, the commercial efficiency of AWE is hindered by high overpotentials caused by the sluggish kinetics of the Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER).

The current work explores the in‐situ formation of TiH₂ additive in a Ti/MgH₂ nanocomposite system. Mild mechanical milling leaves Ti chemically unchanged, while formation of stable TiH_2–x occurs upon strong mechanical milling. TiH_2–x further transforms to TiH₂ upon recycling the powder (dehydrogenation and subsequent hydrogenation) and lowers the activation energy of MgH₂ to 89.4 kJ (mol H₂)⁻¹ [E_a of as‐received MgH₂ is 153 kJ (mol H₂)⁻¹]. This work also reiterates that metallic Ti additive mixed MgH₂ requires strong mechanical milling for better H₂ ab/de‐sorption performance. The current observations support the view that lattice strain may be an important factor in the catalysis of additives incorporated MgH₂ hydrogen storage systems.