Features of the sol-gel process of formation of nanostructured gadolinium oxide

The process of dehydration of Gd(OH)₃·nH₂O obtained by the sol-gel method from a solution of Gd(NO₃)₃, to Gd₂O₃ in the temperature range of 50–700°C was explored. The hydrogel and Gd₂O₃ structurization is shown to depend on the additives (AF-12 and 2-propanol). The final average particle size of Gd₂O₃ after annealing at 700°C is 20±2 nm, depending on the conditions of the synthesis. The resulting oxide particles are larger than the particles of yttrium oxide Y₂O₃ (17±2) obtained under the same conditions of the process due to the higher basicity of gadolinium and its higher coordination number with respect to the OH groups. This promotes the formation of crystalline phases of Gd(OH)₃ at lower temperature, 50–250°C, while maintaining a favorable structural short-range order in passing through an amorphous state to a crystalline Gd₂O₃.