ｇ－Ｃ３Ｎ４／半導体複合材料の構築と表界面制御による二酸化炭素光還元の高機能化

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The project is mainly focused on exploring highly efficient photocatalysts for chemical fuel production based on visible-light responsive organic semiconductor, i.e. carbon nitride. We have been devoted to enhance the charge carrier separation and transport through the following two pathways and have obtained significant progress:1) Constructing an imine-linked antenna-reaction center complex composed of low-molecular-weight carbon nitride and Co porphyrin, where the photo-generated electron-hole is separated more efficiently since electrons could be easily trapped by Co(II) to form Co(I) species and the active site immobilized on the C-N framework facilitated the redox photocatalytic reaction;2) Designing carbon nitride with enhanced in-planar ordering by controlling the self-assembly of heptazine precursors and calcination of the assembled precursors, where the intraplanar transport of the photo-generated charge carriers can be largely enhanced. It was found that the sub-micro rod-like morphology of the assembled heptazine precursor was well maintained during the poly-condensation without volumetric shrinkage in spite of different temperature-rise rates in the calcination process. The enhanced ordering within the graphitic planar and the induced excellent charge separation contributed to a tremendously improved H2 evolution rate of 420 umol/h under visible light (λ > 420 nm) with an apparent quantum efficiency of 8.9% at 420 nm, which is among the highest value for C3N4-related photocatalyst in the literature.