Photocatalytic technology in lignin: from traditional depolymerization to actively light-driven conversion

Lignin is one of the most abundant renewable biopolymers on Earth. In recent years, substantial progress has been achieved in leveraging lignin’s unique properties, especially in the field of photocatalysis. This paper reviews the research progress on lignin-based materials that have been developed through biopolymer engineering techniques, including stages from depolymerization to photocatalytic applications. The role of lignin as a photocatalyst is emphasized, as well as the challenges faced. The relationship between the fundamental structure and properties of lignin is explored, along with the design strategies that are employed to exploit these characteristics. Our review is organized around three main themes: the latest advancements in lignin cleavage technologies (including photocatalytic cleavage), cutting-edge research in lignin-based photocatalytic systems, and the challenges and design strategies associated with the development of lignin photocatalysis. This work aims to contribute significantly to the advancement of sustainable functional photocatalysts derived from lignin. Ultimately, the goal is to develop environmentally friendly and sustainably scalable functional polymer photocatalysts based on lignin in the future.