Covalent organic frameworks for direct photosynthesis of hydrogen peroxide from water, air and sunlight.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37468482.
- Also identified by DOI 10.1038/s41467-023-40007-4 and PMC identifier 10356944.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Solar-driven photosynthesis is a sustainable process for the production of hydrogen peroxide, the efficiency of which is plagued by side reactions. Metal-free covalent organic frameworks (COFs) that can form suitable intermediates and inhibit side reactions show great promise to photo-synthesize H<sub>2</sub>O<sub>2</sub>. However, the insufficient formation and separation/transfer of photogenerated charges in such materials restricts the efficiency of H<sub>2</sub>O<sub>2</sub> production. Herein, we provide a strategy for the design of donor-acceptor COFs to greatly boost H<sub>2</sub>O<sub>2</sub> photosynthesis. We demonstrate that the optimal intramolecular polarity of COFs, achieved by using suitable amounts of phenyl groups as electron donors, can maximize the free charge generation, which leads to high H<sub>2</sub>O<sub>2</sub> yield rates (605 μmol g<sup>-1</sup> h<sup>-1</sup>) from water, oxygen and visible light without sacrificial agents. Combining in-situ characterization with computational calculations, we describe how the triazine N-sites with optimal N 2p states play a crucial role in H<sub>2</sub>O activation and selective oxidation into H<sub>2</sub>O<sub>2</sub>. We further experimentally demonstrate that H<sub>2</sub>O<sub>2</sub> can be efficiently produced in tap, river or sea water with natural sunlight and air for water decontamination.