Supramolecular Perylene Diimides for Photocatalytic Hydrogen Production

Energy depletion and environmental pollution have emerged as pressing global concerns, demanding the urgent promotion of green and clean energy sources. As such, the efficient utilization of solar energy for hydrogen production has gained significant research attention, with semiconductor photocatalysis emerging as an effective strategy. However, harnessing the full potential of semiconductor photocatalysis still poses great challenges. Notably, the limited utilization of visible light and the substantial recombination of photogenerated electron–hole pairs adversely affect photocatalytic performance, ultimately impeding the further development and practical application of semiconductor photocatalysis. Perylene diimide (PDI), an n-type semiconductor distinguished by its conjugated π-π bonds, exhibits remarkable photoelectric properties. Its energy band gap falls within the absorption range of visible light, ensuring remarkable light absorption efficiency. Furthermore, the photogenerated charge can be efficiently conducted along the π-π stacking in its structural unit, significantly reducing electron–hole recombination. Consequently, PDI holds immense potential for achieving visible-light-driven photocatalytic hydrogen production. Yet, despite these attributes, the photocatalytic efficiency of pure PDI is still far from practical use, necessitating innovative modifications to elevate its catalytic performance. In this review, we begin with an in-depth exploration of the principles underlying photocatalytic hydrogen production and discuss various strategies aimed at enhancing photocatalytic performance. We also engage in a comprehensive discussion and summation of the challenges encountered and the future prospects of PDI-based materials. Our endeavor is to pave the way for groundbreaking advancements in the field of photocatalysis, ultimately contributing to a cleaner and more sustainable future.