Scientists have developed an organic framework material that simulates photosynthesis
March 3, 2024
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Scientists at the National University of Singapore (NUS) have created a microporous covalent organic structure containing dense donor-acceptor cages and engineered bonds for the efficient and clean production
Scientists at the National University of Singapore (NUS) have created a microporous covalent organic structure containing dense donor-acceptor cages and engineered bonds for the efficient and clean production of hydrogen peroxide (H).2HE2) using the process of photosynthesis with water and air.
Traditional industrial production H2HE2 The anthraquinone process using hydrogen and oxygen is very energy intensive. This approach uses toxic solvents and expensive precious metal catalysts and produces significant waste from side reactions.
The figure shows a newly developed hexavalent covalent organic material (COF) that mimics photosynthesis. (Left) Light causes the transfer of an electron from a donor site to an acceptor site within the material (shown by red arrows). This process transfers four positive charges to the donor site, which are then used to split water molecules into oxygen (indicated by green arrows). In the acceptor region, two electrons combine with oxygen to form hydrogen peroxide (indicated by the blue arrow). (Right) The structure of the material allows the efficient movement of electrons (shown in yellow), positive charges (shown in blue), water, and oxygen in a single layer. This material has the ability to convert light energy into chemical energy, similar to natural photosynthesis. Credit: National University of Singapore
In contrast, photocatalytic production of H2HE2 It provides an energy-efficient, gentle and clean pathway to oxygen and water. Most importantly, it overcomes common drawbacks of existing photocatalytic systems, such as low activity, extensive use of additional sacrificial alcohol donors, and the need to deliver pure oxygen.
Breakthrough from NUS researchers
A research team led by Professor Jiang Donglin from the NUS Department of Chemistry has developed a new type of photocatalyst for efficient artificial photosynthesis of H.2HE2 from water and air.
Researchers constructed hexavalent covalent organic frameworks (COFs) in which the skeleton was designed as donor–acceptor π pillars for high-speed light-induced charge generation and catalytic active sites. In parallel, the pores are designed with hydraulically responsive trigonal microporous channels for instant delivery of water and oxygen reagents.
As a result, these hexavalent COFs produce H2HE2 spontaneously and efficiently from water and atmospheric air under the influence of visible light in both batch and flow reactors. Under laboratory conditions, COFs exhibit a quantum efficiency of 17.5 percent in visible light at 420 nm in batch reactors. This system can be developed to create self-cleaning surfaces and for disinfection purposes.
The results of the research were recently published in the journal. Nature Catalysis.
Professor Jiang said: “In this work, we have successfully solved the problem of efficiently delivering charge and mass to catalytic centers, which is one of the important and common problems of photocatalysts, electrocatalysts and heterogeneous catalysts. We have relied on atomic-level precise structural design to explore both the skeletons and pores of COFs.” Our focus led to the creation of an artificial photosynthesis system for H production.2HE2achieves unprecedented photocatalytic efficiency.”
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