Linkage effect in the bandgap-broken V2O5-GdCrO3 heterojunction by carbon allotropes for boosting photocatalytic H2 production

Refining carrier transfer in bandgap-broken heterojunctions, which consist of two semiconductors with broken bandgaps, is crucial yet highly challenging for photocatalysis. Herein, we incorporated amorphous carbons (AC) into the bandgap-broken V 2 O 5 /GdCrO 3 heterojunctions, inducing a linkage effect to facilitate photoexcited carrier transfer. The created V-O-C and Cr-O-C bonds in V 2 O 5 -AC-GdCrO 3 interfaces show almost identical orbital energies to overcome the broken-gap energy barriers at interfaces. The holes at GdCrO 3 ’s valence band and electrons at V 2 O 5 ’s conduction band tent to migrating toward the carbon ring of amorphous carbon via Cr-O-C and V-O-C bonds, thereby enhancing carrier separation of bandgap-broken V 2 O 5 /AC/GdCrO 3 heterojunction. By controlling the relative amount of metal-O-C bonds in the interface, the modulation of charge transfer kinetics was also achieved on V 2 O 5 /AC/GdCrO 3 , resulting in ∼7 times higher of H 2 generation than V 2 O 5 /GdCrO 3 . The concept could be expanded to the other carbon allotropes, including graphene, carbon nanotube, and graphdiyne conjugated structures, demonstrating a universal strategy in reaching optimal charge transfer of broken-bandgap heterojunctions for photocatalytic H 2 production.