  Despite significant advancements in electrocatalysis for clean hydrogen fuel
generation, the transition from concept to commercialization faces challenges
due to the instability of electrocatalysts. This study delves into the
exploration of a structurally and mechanically robust half-Heusler alloy,
CoVSn, as an efficient electrocatalyst for hydrogen production. The synthesis
of CoVSn was achieved using the arc-melting technique and optimized
successfully into a cubic structure - a previously unattained and highly
challenging feat. The resulting electrode, cut from the obtained CoVSn pellet,
served as a self-supported electrocatalyst and initially generates a current
density of 10 mA cm-2 at an overpotential of 244 mV. Remarkably, this
overpotential decreased uniquely over time, reaches 202 mV after a durability
testing of 12 hours, while maintaining its crystal structure integrity after
the electrocatalysis process. This progressive enhancement in catalytic
activity and structural stability underscores the significance of this
research. The synergistic effect between Co and V atoms as pivotal active
centers for hydrogen generation was evident, further enhanced by formation of
high valance metal sites Co2O3 and V2O3 during the hydrogen evolution reaction.
In essence, this study confirms the stability and promise of CoVSn in hydrogen
generation, paving the way for exploring additional self-supported ternary
intermetallics to enhance water-splitting efficiency.
