| 研究実績の概要 |
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.
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