Polymeric carbon nitride (PCN) is a promising class of materials for solar‐to‐chemical energy conversion. The increase of the photocatalytic activity of PCN is often achieved by the incorporation of heteroatoms, whose impact on the electronic structure of PCN remains poorly explored. This work reveals that the local electronic structure of PCN is strongly altered by doping with sulfur and iron using X‐ray absorption spectroscopy (XAS) and resonant inelastic X‐ray scattering (RIXS). From XAS at the carbon and nitrogen K‐edges, sulfur atoms are found to mostly affect carbon atoms, in contrast to iron doping mostly altering nitrogen sites. In RIXS at the nitrogen K‐edge, a vibrational progression, affected by iron doping, is evidenced, which is attributed to a vibronic coupling between excited electrons in nitrogen atoms and C–N stretching modes in PCN heterocycling rings. This work opens new perspectives for the characterization of vibronic coupling in polymeric photocatalysts.

中文翻译：

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掺杂剂对聚合氮化碳光催化剂局部电子结构的影响

聚合氮化碳（PCN）是一类很有前途的太阳能到化学能转换材料。PCN 光催化活性的提高通常是通过掺入杂原子来实现的，但杂原子对 PCN 电子结构的影响仍未得到很好的探索。这项工作表明，通过使用 X 射线吸收光谱 (XAS) 和共振非弹性 X 射线散射 (RIXS) 掺杂硫和铁，PCN 的局部电子结构发生了强烈变化。从碳和氮 K 边缘的 XAS，发现硫原子主要影响碳原子，而铁掺杂主要改变氮位点。在氮 K 边缘的 RIXS 中，受铁掺杂影响的振动进程得到证实，这归因于氮原子中的激发电子与 PCN 杂环中的 C-N 伸缩模式之间的振动耦合。这项工作为聚合物光催化剂中振动耦合的表征开辟了新的视角。