Nature uses organic molecules for light harvesting and photosynthesis, but most man-made water splitting catalysts are inorganic semiconductors. Organic photocatalysts, while attractive because of their synthetic tunability, tend to have low quantum efficiencies for water splitting. Here we present a crystalline covalent organic framework (COF) based on a benzo-bis(benzothiophene sulfone) moiety that shows a much higher activity for photochemical hydrogen evolution than its amorphous or semicrystalline counterparts. The COF is stable under long-term visible irradiation and shows steady photochemical hydrogen evolution with a sacrificial electron donor for at least 50 hours. We attribute the high quantum efficiency of fused-sulfone-COF to its crystallinity, its strong visible light absorption, and its wettable, hydrophilic 3.2 nm mesopores. These pores allow the framework to be dye-sensitized, leading to a further 61% enhancement in the hydrogen evolution rate up to 16.3 mmol g⁻¹ h⁻¹. The COF also retained its photocatalytic activity when cast as a thin film onto a support.

大自然使用有机分子进行光收集和光合作用，但是大多数人造水分解催化剂是无机半导体。尽管有机光催化剂因其合成可调性而引人注目，但它们对于水分解的量子效率往往较低。在这里，我们介绍了一种基于苯并双（苯并噻吩砜）部分的结晶共价有机骨架（COF），与无定形或半结晶对应物相比，其光化学氢释放活性更高。COF在长期可见光照射下是稳定的，并且在牺牲电子给体的作用下，至少50小时显示出稳定的光化学氢释放。我们将熔融砜-COF的高量子效率归因于其结晶度，强大的可见光吸收率和可湿性的亲水性3.2 nm中孔。^-1 小时^-1。当以薄膜形式流延到载体上时，COF还保留了其光催化活性。