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

摘要

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 ℃ 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 MOF-catalyst assembly was found to have lower overpotential requirements,owing to an increase in local acidity and efficient proton management around the catalyst.