Photocatalytic lignin depolymerization is an important pathway to extend lignin application. The application of deep eutectic solvent (DES) realize green chemistry closed-up due to avoid using organic solvent. In this work, photocatalytic cleavage lignin β-O-4 bonds with Bi2O3/Bi2WO6 in DES is developed. DES composition is betaine: citric acid (1.2:1.0, moisture content: 60 %). A certain quantity of H2O can decrease viscosity and increase conductivity of DES at room temperature. In addition, Bi2O3/Bi2WO6 (1:1) photocatalyst which can break β-O-4 bond selectively at visible light is designed. The Bi2O3/Bi2WO6 1:1 catalyst has flower-structure and the formation of p-n heterostructures attributes to ordered structure result to the increase of photocatalytic efficiency. Lignin model compound depolymerization efficiency was 85.62 %. Finally, we applied this method to depolymerize real lignin separated from spruce. The depolymerization efficiency was 24.74 % (Klason lignin, KL), 26.43 % (dioxane lignin, DL), and 32.25 % (alkali lignin, AL), respectively. The application of DES and photocatalytic will be the key point for large-scale biorefineries by green method.

中文翻译：

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绿色化学闭环：室温下低共熔溶剂中Bi2O3/Bi2WO6利用可见光光催化裂解木质素β-O-4键


光催化木质素解聚是扩大木质素应用的重要途径。低共熔溶剂(DES)的应用由于避免使用有机溶剂而实现了绿色化学封闭。在这项工作中，开发了 DES 中光催化裂解木质素 β-O-4 与 Bi2O3/Bi2WO6 键的方法。 DES的组成为甜菜碱：柠檬酸（1.2:1.0，水分含量：60%）。一定量的H2O可以降低DES在室温下的粘度并增加其电导率。此外，还设计了可在可见光下选择性断裂β-O-4键的Bi2O3/Bi2WO6（1:1）光催化剂。 Bi2O3/Bi2WO6 1:1催化剂具有花状结构，并且形成属于有序结构的pn异质结构，从而提高了光催化效率。木质素模型化合物解聚效率为85.62%。最后，我们应用该方法对从云杉中分离出的真实木质素进行解聚。解聚效率分别为24.74%（克拉森木质素，KL）、26.43%（二恶烷木质素，DL）和32.25%（碱木质素，AL）。 DES和光催化的应用将是绿色方法大规模生物炼制的关键。