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

该项目主要致力于探索基于可见光响应有机半导体（即氮化碳）的高效化学燃料生产光催化剂。我们致力于通过以下两条途径来提高载流子的分离和传输，并取得了显著的进展：1）构建了一种由低分子量氮化碳和钴卟啉组成的亚胺连接的天线-反应中心复合物，由于电子容易被Co（II）捕获形成Co（I）物种，并且固定在C-N骨架上的活性位点促进了氧化还原光催化反应，因此可以更有效地分离光生电子-空穴; 2）通过控制七嗪前体的自组装和组装前体的煅烧来设计具有增强的面内有序的氮化碳，其中光生电荷载流子的面内传输可以大大增强。结果发现，组装的七嗪前体的亚微米棒状形态保持良好的缩聚过程中没有体积收缩，尽管在煅烧过程中的不同的升温速率。石墨平面内增强的有序性和诱导的优异的电荷分离有助于在可见光（λ > 420 nm）下极大地提高420 umol/h的H2放出速率，在420 nm处的表观量子效率为8.9%，这是文献中C3 N4相关光催化剂的最高值之一。

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.