Constructing Large-Area Oriented Covalent Organic Framework Based PN Heterostructure Films to Enhance Artificial
Minghui Liu1,2, Yachao Xu3, Youxing Liu3,4
1Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P.R. China.
Abstract:
Two-dimensional conjugated covalent organic framework (COF) films exhibit enormous application potential in the photosynthesis of hydrogen peroxide (H2O2), however, they suffer from various photogenerated electron-hole recombination. Herein, we first report a new strategy of in situ constructing oriented COF-based PN heterostructure film through single-layer MoS2 induced growth, significantly enhancing the photogenerated carrier separation efficiency, which promotes the photocatalytic H2O2 synthesis. Experimental results reveal that the as-made oriented TAPB-DMTA COF/MoS2 (TAPB: 1,3,5-tris(4-aminophenyl) benzene, DMTA: 2,5-Dimethoxyterephthalaldehyde) film exhibits a high photocatalytic H2O2 yield of 8154 µmol g-1 h-1, which is ∼2.5 times and ∼4 times higher than that of non-oriented TAPB-DMTA COF films and powder. The mechanism reveals that the oriented structure of the TAPB-DMTA COF can significantly promote the generation and the transmission of photogenerated electron-hole pairs along the skeleton and layer-by-layer stacking direction, thus enhancing the photocatalytic H2O2 performance. The new strategy of in situ constructing oriented COFs-based PN heterostructure film for enhancing the photosynthesis of H2O2 will open the door to rational design of molecular films towards high photogenerated carrier separation efficiency.
