A 3D open-framework iron hydrogenophosphate showing high proton conductance under water and aqua-ammonia vapor

摘要

Herein we report the first example of the proton conductivity of an open-framework metal phosphate (NH _(3) (CH _(2) ) _(3) NH _(3) ) _(2) –[Fe _(4) (OH) _(3) (HPO _(4) ) _(2) (PO _(4) ) _(3) ]·4H _(2) O under aqua-ammonia vapor. Its optimized proton conductivity is 5 × 10 ~(?2) S cm ~(?1) at 313 K and aqua-ammonium vapor from 1 M NH _(3) ·H _(2) O solution. That is approximately two orders of magnitude greater than the maximum value under water vapor (8.0 × 10 ~(?4) S cm ~(?1) at 317 K and 99% RH). The proton transfer mechanism has been proposed in terms of the structural analyses, activation energy calculations, and PXRD determinations.