2D/2D Hydrogen-Bonded Organic Frameworks/Covalent Organic Frameworks S-Scheme Heterojunctions for Photocatalytic Hydrogen Evolution

Abstract

Hydrogen-bonded organic frameworks (HOFs) demonstrate significant potential for application in photocatalysis. However, the low efficiency of electron-hole separation and limited stability inhibit their practical utilization in photocatalytic hydrogen evolution from water splitting. Herein, the novel dual-pyrene-base supramolecular HOF/COF 2D/2D S-scheme heterojunction between HOF-H₄TBAPy (Py-HOF, H₄TBAPy represents the 1,3,6,8-tetrakis (p-benzoic acid) pyrene) and Py-COF was successfully established using a rapid self-assembly solution dispersion method. Experimental and theoretical investigations confirm that the size-matching of two crystalline porous materials enables the integrated heterostructure material with abundant surface reaction sites, strong interaction, and an enhanced S-scheme built-in electric field, thus significantly improving the efficiency of photogenerated charge carrier separation and stability. Notably, the optimal HOF/COF heterojunction achieves a photocatalytic hydrogen evolution rate of 390.68 mmol g⁻¹ h⁻¹, which is 2.28 times higher than that of pure Py-HOF and 9.24 times higher than that of pure COF. These findings precisely acquire valuable atomic-scale insights into the ingenious design of dual-pyrene-based S-scheme heterojunction. This work presents an innovative perspective for forming supramolecular S-scheme heterojunctions over HOF-based semiconductors, offering a protocol for designing the powerful and strong-coupling S-scheme built-in electric fields for efficient solar energy utilization.