研究実績の概要 |
Covalent organic frameworks (COFs) are a unique class of crystalline porous organic polymer that enables the construction of ordered one-dimensional mesoporous channels with a wide range of promising applications such as adsorption, catalysis, semiconductor, sensing and super capacitors. I introduced crystalline H3PO4 to the pores of a stable TAPT-DMTP-COF and produced H3PO4@TAPT-DMTP-COF with different contents of H3PO4 in the pores. Notably, the H3PO4@TAPT-DMTP-COF achieves an exceptional proton conductivity up to 10^-2 S cm^-1at 160 °C. Previously our group has been successfully developed the concept that the mesoporous channels of crystalline covalent organic frameworks can be designed to be the container of the proton carriers and the proton conductivity has been 2-4 orders of magnitude higher than those of microporous and nonporous polymers. Then I also designed and synthesized COFs with polyelectrolyte units on pore walls by using pore surface engineering method and stable COFs as a precursor. The OH--appended COFs exhibited high OH- conduction. The conductivity of hydroxide ions along the ordered chains reached to 10^-4 S cm^-1 at 80 °C in water, which are four orders of magnitude higher than those of porous polymers reported. The hydroxide ion conduction requires low activation energy of 0.16 eV and occurs via a mechanism of proton hopping in the hydrogen network. These results suggest a new way based on crystalline porous covalent organic frameworks for designing anion-conducting materials.
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