Covalent organic frameworks (COFs) have shown great advantages as photocatalysts for hydrogen evolution. However, the effect of linkage geometry and type of linkage on the extent of π-electron conjugation in the plane of the framework and photocatalytic properties of COFs remains a significant challenge. Herein, two Kagome (kgm) topologic oligo(phenylenevinylene)-based COFs are designed and synthesized for boosting photocatalytic hydrogen evolution via a "two in one" strategy. Under visible light irradiation, COF-954 with 5 wt% Pt as cocatalyst exhibits high hydrogen evolution rate (HER) of 137.23 mmol g-1 h-1 , outperforming most reported COF-based photocatalysts. More importantly, even in natural seawater, COF-954 shows an average HER of 191.70 mmol g-1 h-1 under ultraviolet-visible (UV-vis) light irradiation. Additionally, the water-drainage experiments indoors and outdoors demonstrate that 25 and 8 mL hydrogen gas could be produced in 80 min under UV-vis light and natural sunlight, respectively, corresponding to a high HER of 167.41 and 53.57 mmol h-1 g-1 . This work not only demonstrates an effective design strategy toward highly efficient COF-based photocatalysts, but also shows the great potential of using the COF-based photocatalysts for photocatalytic hydrogen evolution.
Keywords: covalent organic framework; phenylenevinylene; photocatalytic hydrogen evolution; “two in one” strategy.
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