Zwitterionic hydrogen-bonded organic framework (ZHOF): a metal-free water oxidation proton relay in alkaline and neutral media. Issue 3 (4th January 2023)

• Record Type: Journal Article
• Authors: Azizi, Roghayeh; Shamsipur, Mojtaba; Taherpour, Avat (Arman); Pashabadi, Afshin
• Is Part Of: Journal of materials chemistry. Volume 11:Issue 3(2023)
• Page Start: 1491
• Page End: 1502
• Publication Date: 2023-01-04
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2ta08387f
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Graphite supported zwitterionic hydrogen-bonded organic framework (ZHOF) acts as a supercapacitor, and proton relay during water oxidation reactions in alkaline and natural media. Abstract : This work reports the synthesis of a single crystalline zwitterionic hydrogen-bonded organic framework (ZHOF) by utilizing 1, 4, 8, 11-tetraazacyclotetradecane-1, 4, 8, 11-tetraacetic acid (H4 TATA) ligand. A modified solvothermal method employs a non-bulky polar solvent system, allowing maximum interpenetration of zwitterionic skeletons (ZSs). The results of single-crystal X-ray diffraction analysis display a two-dimensional (2D) extension of ZSs through strong H-bonding (HB), asymmetric Speakman-type, between carboxyl and carboxylate groups. The sheets are latched and knotted through two-per-tecton zwitterionic intermolecular interactions of the ammonium–carboxylate motif. The 2D sheets are assembled in a third dimension through an AB pattern in the form of a pseudo-laminated 3D framework with an interlayer spacing of 3.64 Å, providing a water-included rigid proton-conduction channel in the course of the water oxidation reaction. The metal-free graphite-supported ZHOF (FGF/ZHOF) shows striking performance as a water oxidation proton relay in alkaline and neutral media. The proton/deuterium isotopic studies unraveled accelerating proton transfer (PT) on FGF/ZHOF with a secondary kinetic isotopic effect ( k H / k D, KIE) as low as 1.15. The post-metalation of ZHOF affords a primary KIE value of 3.3, with a reversible overtaking of the electron transfer against PT. The observation of Gerischer impedance approves an efficient protonic species translocation at exchange sites through a practically blocked natural diffusion. The FGF/ZHOF displays a promising charge storage ability with a specific capacitance of 903 F g −1 .