Recent progress in the development of self-assembled porphyrin derivatives for photocatalytic hydrogen evolution

Photocatalytic hydrogen evolution (PHE) offers a promising solution to mitigate environmental pollution and address the global energy crisis. Porphyrin derivatives have been extensively explored as photocatalysts for PHE, owing to their efficient light-harvesting ability in the UV-Vis absorption region, stable photoexcited states, reversible redox properties, high photo and chemical stabilities, and tailorable optoelectronic properties via structural engineering. However, the monomeric porphyrin photocatalysts typically exhibit a narrow absorption range in the visible spectrum, susceptibility to light corrosion, and difficulty in loading cocatalysts such as Pt due to limited interface contact area. These issues lead to a low electron transfer efficiency between monomeric porphyrin photocatalyst and cocatalyst and thus inferior PHE performance. In addition, porphyrin photocatalysts in their bulk powder form usually possess uncontrolled morphologies and thus inefficient separation and migration of photoinduced charge carriers, which subsequently lowers the PHE performance. To address these challenges, the development of self-assembled porphyrin derivatives with well-defined sizes and shapes in the solid state presents a promising strategy. Over the past decade, significant advancements have been made in creating porphyrin-based self-assembled materials for efficient PHE. In this review, we summarize the progress in developing porphyrin-based self-assembled materials for PHE, highlighting how the morphology of selfassembled porphyrins affects their light-harvesting abilities, electronic properties, and separation and migration of photoinduced charge carriers, ultimately impacting their PHE performances. We are optimistic that this review will guide the future development of innovative self-assembled porphyrins, enhancing their efficacy for PHE and broadening their applications across various areas.