Acetylene and Diacetylene Functionalized Covalent Triazine Frameworks as Metal-Free Photocatalysts for Hydrogen Peroxide Production: A New Two-Electron Water Oxidation Pathway |
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Authors: | Liang Chen Lei Wang Yangyang Wan Ying Zhang Zeming Qi Xiaojun Wu Hangxun Xu |
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Affiliation: | 1. Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui, 230026 China;2. Hefei National Laboratory for Physical Sciences at the Microscale, CAS Center for Excellence in Nanoscience, Department of Materials Science and Engineering, CAS Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei, Anhui, 230026 China;3. National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, 230029 China |
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Abstract: | Metal-free polymer photocatalysts have shown great promise for photocatalytic H2O2 production via two-electron reduction of molecular O2. The other half-reaction, which is the two-electron oxidation of water, still remains elusive toward H2O2 production. However, enabling this water oxidation pathway is critically important to improve the yield and maximize atom utilization efficiency. It is shown that introducing acetylene ( CC ) or diacetylene ( CC CC ) moieties into covalent triazine frameworks (CTFs) can remarkably promote photocatalytic H2O2 production. This enhancement is inherent to the incorporated carbon–carbon triple bonds which are essential in modulating the electronic structures of CTFs and suppressing charge recombinations. Furthermore, the acetylene and diacetylene moieties can significantly reduce the energy associated with OH* formation and thus enable a new two-electron oxidation pathway toward H2O2 production. The study unveils an important reaction pathway toward photocatalytic H2O2 production, reflecting that precise control over the chemical structures of polymer photocatalysts is vital to achieve efficient solar-to-chemical energy conversion. |
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Keywords: | 2D polymers covalent triazine frameworks hydrogen peroxide photocatalysis two-electron process |
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