Emerging hydrogel and hydrogel-derived nanoarchitectonics for photocatalysis and electrocatalysis in sustainable energy and chemical applications.

The quest for green and sustainable energy presents a paramount challenge in today's society. Photo- and electrocatalytic reactions have garnered growing research interest due to their potential to harness renewable energy sources. However, these processes still face critical obstacles, such as poor catalytic efficiency and material durability. Notably, hydrogel and hydrogel-derived materials, characterized by their interconnected network structures and tunable mechanochemical properties, offer a promising avenue for advancing ideal catalytic reaction materials. The nanostructures of these materials can effectively overcome the limitation of current catalytic designs, enhancing catalytic performance. This review provides a comprehensive review of research progress surrounding multifunctional hydrogel and hydrogel-derived for photo- and electro- catalytic reactions. It begins by architecture design of the hydrogel catalytic system and introducing various synthesis strategies for hydrogel and hydrogel-derived catalyst composite. The review then describes the key properties of hydrogels, such as mechanical, swelling, stimuli-responsive, conductive properties, local chemical microenvironment and triple-phase interface engineering. It also explores their roles in critical reactions such as oxygen reduction reaction, oxygen evolution reaction, hydrogen evolution reaction, hydrogen oxidation reaction, ammonia formation reaction, carbon dioxide reduction, hydrogen peroxide production, as well as applications in plastic degradation and organic molecule transformation, showcasing the unparalleled potential of these materials. Lastly, the challenges and opportunities surrounding use of hydrogel and hydrogel-derived catalytic composites are summarized, offering insights into future developments for a greener, more sustainable world.