MOFs have highly ordered structures and modular nature that can serve as a scaffold to anchor acidic groups and improve efficient proton transfer pathways. HKUST-1, a MOF material containing CuII–paddle wheel type nodes and 1,3,5-benzenetricarboxylate struts, feature accessible sites to which solvent or other desired molecules can be intentionally coordinated to improve proton conductivity. In spite of the fact that HKUST-1 is neutral, coordinated water molecules are contributed adequately acidic by CuII to supply protons to enhance proton conductivity. On the other hand, organic proton conductor Nafion® has high synthetic variability because they can have various chemical components. Using the concept of coordination network Nafion® is tuned by HKUST-1 that makes improved protonic channel depending on water content. In this study, coordination network formed by HKUST-1 into the Nafion® certainly improved the water content and H2O-HK yields larger proton conductivity comparing to other solvents due to the participation of coordinated water molecules as proton donors. Water molecules serve as triggers to transfer protons through reforming hydrogen bonding networks by water adsorption/desorption process. The role of CuII is to enhance the acidity of ligated H2O, a proposal for which there is ample chemical precedent.
Journal: TechConnect Briefs
Volume: 2, Materials for Energy, Efficiency and Sustainability: TechConnect Briefs 2015
Published: June 14, 2015
Pages: 53 - 56
Industry sector: Energy & Sustainability
Topic: Fuel cells & Hydrogen