A novel bimetallic 3-D organic-inorganic hybrid vanadoborate architecture with exceptional proton conductivity

Abstract

The synthesis of a novel bimetallic organic-inorganic hybrid vanadoborate K8Cu(en)2[(VO)12O6B18O36(OH)6]·14H2O (1, en = ethylenediamine) with a three-dimensional (3-D) open-framework was achieved through hydrothermal reactions. Compound 1 consists of anionic 1-D chains arranged in parallel along the [001] direction, constructed by corner-sharing [Cu(en)2]2+ cations and hamburger-like V12B18 anionic clusters. The K-O polyhedra act as linkers to further connect with the 1-D chains, resulting in the 3-D architecture featuring extensive hydrogen bonding networks. Significantly, compound 1 demonstrated proton conductivity values of up to 3.09 × 10–3 S/cm at a temperature of 318 K and under conditions of 100 % relative humidity. Moreover, it exhibited an activation energy of 1.46 eV at various temperatures in the presence of complete humidity, thereby establishing compound 1 as a remarkably proficient solid conductive material.