Mechanochemical synthesis of niobium pentoxide nanoparticles

Abstract

Synthesis of Nb2O5 nanoparticles by mechanochemical processing has been investigated. The reactions 2NbCl5 + 5Na2CO3 → Nb2O5 + 10NaCl + 5CO2(g) and 2NbCl5 + 5MgO → Nb2O5 + 5MgCl2 led to the formation of Nb2O5 aggregates of 100-1000 nm in size. Addition of NaCl in the starting mixture of 2NbCl5 + 5Na2CO3 prevented the aggregates forming. After heat treatment of the as-milled powder at 300°C, amorphous Nb2O5 having a high surface area of 196 m2/g was obtained. Heat treatment at 550° resulted in a powder consisting of 10-100 nm single crystal Nb2O5 particles along with a network of ultrafine amorphous particles. Annealing at higher temperature led to the formation of the Na2Nb2O11 phase.