Effect of KOH concentration on the hydrothermal synthesis of Bi_(1.5)ZnNb_(1.5)O_7 nanopowder

The Bi1.5ZnNb1.5O7 nanopowder was successfully synthesized by hydrothermal method (HTM) with Bi(NO3)3·5H2O, ZnO and Nb2O5 as starting materials and KOH as mineralizer. According to the growth unit model of anion coordination polyhedron, the effects of KOH concentrations on the phase, particle size and morphology of nanopowder were investigated. The results show that the Bi1.5ZnNb1.5O7 nanopowder with cubic pyrochlore phase can be obtained by HTM, and its morphology is of granular shape. The formation of stable growth unit is the major reason that effects the particle size of Bi1.5ZnNb1.5O7 powder, which is affected by the KOH concentration, but the morphology of powder does not change. The minimum particle size of powder is 51 nm and the maximum specific surface area is 28.8 m2/g when the Bi1.5ZnNb1.5O7 powder is synthesized by HTM with a synthesis temperature of 220 ℃, a reaction time of 24 h, and a KOH molar concentration of 1.8 mol/L.