Revealing the dynamics of charge carriers in organic/inorganic hybrid FS-COF/WO3 S-scheme heterojunction for boosted photocatalytic hydrogen evolution

This work designed and built unique S-scheme heterojunctions by in-situ growing inorganic WO3 nanoparticles with excellent oxidation ability on fused-sulfone-modified covalent organic frameworks (FS-COF) with strong reduction ability.

It is found that FS-COF and WO3 have a well-matched staggered band alignment. The best-designed FS-COF/WO3-20% exhibits a maximum photocatalytic HER rate of 24.7 mmol g-1 h-1 under visible light irradiation, which is 1.4 times greater than the pure FS-COF. Moreover, photogenerated electron-hole pairs can be separated and utilized more efficiently thanks to the FS-COF/WO3 heterojunction's ability to create a favorable internal electric field resulting from the difference in work functions between FS-COF and WO3, which speeds up the transfer dynamics of photoinduced electrons from WO3 to FS-COF through an additional interfacial electron-transfer channel obeying the directional S-scheme migration mechanism.