In situ growing graphene on g-C3N4 with barrier-free interface and polarization electric field for strongly boosting solar energy conversion into H2 energy

In-situ growth of graphene on g-C3N4 (GC3N4) with sp2-hybridized N atoms at triangular caves as growing sites has been achieved with a tight barrier-free interface and intrinsic spontaneous polarization electric field (ISPEF) for simultaneously driving charge segregation and transfer from bulk to redox sites of surface, as confirmed by Hall effect and theoretical predictions. Consequently, the polarized GC3N4 photocatalyst without any cocatalyst demonstrates a super high efficiency of 18.9 mmol∙g−1 h−1 with a large amount of visual H2 bubbles under visible light illumination, which is the best metal-free photocatalysts for H2O splitting into H2 fuel so far. This research supplies a novel and facile strategy to in situ grow graphene on pristine carbon materials with ISPEF to break the shackle of cocatalyst usage such as noble metals for commercial promotion to solar energy conversion.