Role of alloying elements in vanadium-based binary alloy membranes for hydrogen separation

► In vanadium-based alloys, Al strongly repels interstitial hydrogen while Ti attracts it. ► Ni stabilizes octahedral interstitial sites which are not stable in pure V. ► Strong repulsion by Al decreases the configurational entropy of the system. ► Large alloying elements in general stabilize interstitial hydrogen.