Defect Engineering in a Metal-Organic Framework System to Achieve Super-Protonic Conductivity

Controlled incorporation of missing-linker defect sites could be achieved in four sister metal-organic frameworks (MOFs) of MOF-808, namely, MOF-808 A-D via modulated synthesis. An impressive enhancement in proton conductivity is observed in these sister MOFs (increase from 10-3 to 10-1 S cm-1) as compared to a highly crystalline, low-in-defect variant of MOF-808. MOF-808 C, having optimized defect density, shows a proton conductivity of 2.6 x 10-1 S cm-1 at 80 & DEG;C and 98% relative humidity-the highest value reported to date for pure MOF-based proton conductors without extensive structural modifications. The introduction of defects induces super-protonic conductivity by modifying different properties, like porosity, water sorptivity, and acidity. Furthermore, an assembly of this super proton-conducting MOF with Pt?a versatile hydrogen evolution reaction (HER) catalyst, has been studied with the objective to influence the catalytic activity. This MOFcatalyst assembly was found to have lower overpotential requirements, owing to an increase in local acidity and efficient proton management around the catalyst.