To obtain high-valued aromatic products, it is paramount to cleave the C−C bonds in lignin under mild conditions selectively. Nevertheless, this task remains daunting due to the formidable dissociation energies and steric hindrance associated with these bonds. Herein, a facile, efficient and cost-effective strategy for selectively breaking the C−C bond in lignin with visible-light irradiation and room temperature is proposed, facilitated by the utilization of the ferric-doped mesoporous graphitic carbon nitride (Fe/mpg-CN) photocatalyst. Collective contributed by the reduced band gap and photoluminescence, combined with intensified visible-light absorption and enhanced photocurrent, the effectiveness in photocatalytic activity of Fe/mpg-CN is offered. Specifically, a high conversion rate (98 %) of the lignin model compound (2-phenoxy-1-phenylethanol), coupled with an excellent selectivity of 98 % in cleaving the C−C bonds is achieved by Fe/mpg-CN. Photogenerated holes are indicated as the main active species through comprehensive mechanistic investigations. Additionally, the successful photocatalytic depolymerization of the complex dimer model compound (conversion rate ∼ 96 %) and pine kraft lignin further corroborate the satisfying photocatalytic activity and selectivity of Fe/mpg-CN. This study introduces a promising and viable strategy for the selective breaking of lignin through photocatalysis, offering significant implications for the sustainable production of valuable aromatic compounds.

中文翻译：

---

Fe掺杂介孔石墨氮化碳光催化剂在可见光下有效选择性裂解木质素中的CC键


为了获得高价值的芳香产品，在温和的条件下选择性地裂解木质素中的CC键至关重要。然而，由于与这些键相关的强大的解离能和空间位阻，这项任务仍然令人畏惧。在此，提出了一种在可见光照射和室温下选择性断裂木质素中 C−C 键的简便、高效且经济有效的策略，通过利用铁掺杂介孔石墨碳氮化物（Fe/mpg- CN）光催化剂。由于带隙减小和光致发光，再加上可见光吸收增强和光电流增强，Fe/mpg-CN 的光催化活性得到了提高。具体而言，Fe/mpg-CN 实现了木质素模型化合物（2-苯氧基-1-苯基乙醇）的高转化率（98%），同时在裂解 CC 键方面具有 98% 的优异选择性。通过综合机理研究表明光生空穴是主要的活性物质。此外，复杂二聚体模型化合物（转化率~96%）和松木牛皮纸木质素的成功光催化解聚进一步证实了Fe/mpg-CN令人满意的光催化活性和选择性。这项研究提出了一种通过光催化选择性分解木质素的有前途且可行的策略，为有价值的芳香化合物的可持续生产提供了重要意义。