Ultrafast charge transfer in TiO2/Py-HOF S-scheme heterojunction for highly photocatalytic H2O2 production and sterilization

A stable Py-HOF was prepared by employing H 4 TBAPy as precursor. • A TiO 2 /Py-HOF composite with excellent photocatalytic activity was constructed. • T/Py-HOF shows stability due to strong H-bonds and π–π interactions of H 4 TBAPy. • S-scheme charge transfer pathway was verified via ISI-XPS, fs-TAS, and DFT. • T/Py-HOF display good photocatalytic H 2 O 2 production yield and sterilization. Hydrogen-bonded organic frameworks (HOFs) hold substantial potential for application in photocatalysis. However, their practical application in photocatalytic H 2 O 2 generation and antibacterial activity remains hampered by intrinsically inefficient electron-hole separation and inadequate structural stability. Herein, a Py-HOF photocatalyst was prepared by employing 1,3,6,8-tetrakis (p-benzoic acid) pyrene (H 4 TBAPy) as precursor via self-assembly method, and the titanium dioxide/Hydrogen-bonded organic framework (TiO 2 /Py-HOF, T/Py-HOF) S-scheme heterojunction was rationally fabricated via an in-situ synthesis. Due to the strong hydrogen bonds and π–π interactions of H 4 TBAPy, the T/Py-HOF S-scheme heterojunction displays super stability. Furthermore, in-situ irradiated XPS, femtosecond transient absorption spectroscopy, and DFT calculations verify the S-scheme carrier migration mechanism within the T/Py-HOF heterojunction. Thanks to the ultrafast charge-transfer and excellent redox ability of the T/Py-HOF S-scheme photocatalyst, the optimally formulated T/Py-HOF-5% achieves a remarkable H 2 O 2 production rate of 1890 μmol g −1 h −1 , corresponding to approximately 15.24 and 6.19-fold enhancements compare to the pure TiO 2 and bare Py-HOF, respectively, along with excellent stability. Furthermore, the T/Py-HOF heterojunction also exhibits superior photocatalytic sterilization activity against Escherichia coli (E. coli) , achieving almost 100% of E. coli inactivation after 90 min light irradiation. Collectively, this work offers a novel insight for designing high-efficiency HOF-based S-scheme photocatalysts in energy and environment applications. A novel TiO 2 /Py-HOF S-scheme heterojunction was fabricated for efficient photocatalytic H 2 O 2 production and excellent photocatalytic E. coli sterilization. Download: Download high-res image (202KB) Download: Download full-size image