In-plane coupling electric field driving charge directional transfer for highly efficient H2 bubble evolution

Abstract Directional charge transfer across in-plane structure of g-C3N4 is still inefficient because of the uniform delocalization charge distribution around triangular caves of the π-conjugated tri-s-triazine polymer, which severely restricts its application in solar energy conversion into H2 fuel. Herein, an in-plane coupling electric field is introduced to boost charge directional transfer by coupling Li+ with sp2-hybridized N ligand at triangular cave of g-C3N4 (LiC3N4) for highly efficient H2 bubble evolution. The constructed LiC3N4 demonstrates much high H2-evolution efficiency with a large number of visible H2 bubbles, which presents absolute performance advantage and industrial potential in comparison with g-C3N4 supported numerous noble metals. Density functional theory and characterizations reveal an efficient charge directional transfer from the 2pz orbit of sp2-hybridized N ligand to Li atom across in-plane structure of LiC3N4 is achieved under the coupling electric field, resulting in an efficient H2 bubble evolution. This research strategy shows a scientific perspective to boost directional charge transfer for much effective solar energy conversion into H2 fuel by Li+ coupling effect, which will be bound to introduce the competition for lithium resources between photocatalytic solar energy conversion and lithium batteries.