Designing high-efficiency photocatalysts by the construction of organic/inorganic heterojunctions is considered to be an effective approach for improving photocatalytic hydrogen evolution reaction(HER)activity.This wo...Designing high-efficiency photocatalysts by the construction of organic/inorganic heterojunctions is considered to be an effective approach for improving photocatalytic hydrogen evolution reaction(HER)activity.This work designed and built unique S-scheme heterojunctions by in-situ growing inorganic WO_(3) 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 WO_(3) have a well-matched staggered band alignment.The best-designed FS-COF/WO_(3)-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/WO_(3) heterojunction's ability to create a favorable internal electric field resulting from the difference in work functions between FS-COF and WO_(3),which speeds up the transfer dynamics of photoinduced electrons from WO_(3) to FS-COF through an additional interfacial electron-transfer channel obeying the directional S-scheme migration mechanism.Furthermore,the S-scheme migration mechanism of photoinduced charge carriers instead of the type-II mechanism was confirmed by the signal intensity of•O_(2)−species from spin-trapping electron paramagnetic resonance spectra over the single component and the formed heterojunction.It ensures the photoexcited electrons maintain on the lowest unoccupied molecular orbital of FS-COF with a strong reduction ability to participate in photocatalytic HER,resulting in a significantly boosted H_(2) evolution rate.Based on organic/inorganic coupling,this work offers a strategy for creating particular S-scheme heterojunction photocatalysts.展开更多
文摘Designing high-efficiency photocatalysts by the construction of organic/inorganic heterojunctions is considered to be an effective approach for improving photocatalytic hydrogen evolution reaction(HER)activity.This work designed and built unique S-scheme heterojunctions by in-situ growing inorganic WO_(3) 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 WO_(3) have a well-matched staggered band alignment.The best-designed FS-COF/WO_(3)-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/WO_(3) heterojunction's ability to create a favorable internal electric field resulting from the difference in work functions between FS-COF and WO_(3),which speeds up the transfer dynamics of photoinduced electrons from WO_(3) to FS-COF through an additional interfacial electron-transfer channel obeying the directional S-scheme migration mechanism.Furthermore,the S-scheme migration mechanism of photoinduced charge carriers instead of the type-II mechanism was confirmed by the signal intensity of•O_(2)−species from spin-trapping electron paramagnetic resonance spectra over the single component and the formed heterojunction.It ensures the photoexcited electrons maintain on the lowest unoccupied molecular orbital of FS-COF with a strong reduction ability to participate in photocatalytic HER,resulting in a significantly boosted H_(2) evolution rate.Based on organic/inorganic coupling,this work offers a strategy for creating particular S-scheme heterojunction photocatalysts.
