RT Journal Article
T1 High Surface Proton Conduction in Nanostructured ZIF-8
A1 Muñoz Gil, Daniel
A1 Figueiredo, Filipe
AB The zeolitic imidazolate framework-8 (ZIF-8) combines a significantly high microporosity with an excellent thermal, chemical, and hydrothermal stability. Here, we demonstrated that ZIF-8 can display significant levels of protonic conductivity through a water-mediated surface transport mechanism associated to the presence of di-coordinated Zn ions revealed by X-ray photoelectron spectroscopy. A set of powders with particle sizes from 2.8  m down to 80 nm studied by dynamic water vapour sorption analysis was used to demonstrate that water adsorbs predominantly in the micropore cavities of microcrystalline ZIF-8, whereas adsorption on the external surface becomes the dominant contribution for the nanostructured material. Impedance spectroscopy in turn revealed that the protonic conductivity of the nanocrystalline ZIF-8 was two orders of magnitude higher than that of the micron-sized powders, reaching approximately 0.5 mS·cm-1 at 94 ºC and 98% relative humidity. Simple relations were derived in order to estimate the potential gains in water uptake and conductivity as a function of the particle size. This new strategy combining particle nanostructuring with surface defects, demonstrated here for one of the most know metal organic framework, is of general application to potentially boost the conductivity of other materials avoiding chemical functionalization strategies that in most if not all cases compromise their chemical stability, particularly under high humidity and high temperature conditions.
PB Multidisciplinary Digital Publishing Institute
SN 2079-4991
YR 2019
FD 2019
LK https://hdl.handle.net/20.500.14352/94308
UL https://hdl.handle.net/20.500.14352/94308
LA eng
NO Muñoz-Gil, D.; Figueiredo, F.M.L. High Surface Proton Conduction in Nanostructured ZIF-8. Nanomaterials 2019, 9, 1369. https://doi.org/10.3390/nano9101369
NO European Commission
NO Portuguese Foundation for Science and Technology
DS Docta Complutense
RD 25 abr 2025