In situ construction of a multi-hierarchical CdS-DETA/In(OH)3/Ag2S dual-S-scheme heterojunction for accurate depolymerization of the β-O-4 bond in lignin compounds

Abstract

Nowadays, photocatalysis has emerged as a highly promising approach for the selective depolymerization of lignin under mild conditions due to its ability to generate reactive species with high redox capabilities in a single step. In this study, a ternary nanocomposite photocatalyst, CdS-DETA/In(OH)₃/Ag₂S, was synthesized using in situ assembly and ion exchange methods. This approach was chosen to address the shortcomings of traditional preparation methods, which often lead to the mutual coverage or occupation of different materials, making it difficult to achieve synergistic oxidation and reduction of lignin. Compared to the original CdS-DETA, In(OH)₃, and CdS-DETA/In(OH)₃, the constructed ternary nanocomposite photocatalyst was found to form a unique dual-S-scheme heterojunction. This structure not only effectively enhances light-harvesting capabilities but also enables the efficient separation and transfer of photogenerated charge carriers. Consequently, the photocatalyst exhibits good photocatalytic activity in the depolymerization of the lignin model compound (2-phenoxy-1-phenylethanol). The mechanism of the dual-S-scheme heterojunction in the photocatalyst was proposed, and its effectiveness in improving light absorption and facilitating the separation and transfer of photogenerated carriers was demonstrated.