Room-temperature synthesis of Bi4Ge3O12from aqueous solution

Single-phase bismuth germanate (Bi4Ge3O12 abbreviated as BGO) powder was successfully synthesized by means of a room-temperature chemical process under atmospheric pressure. This was achieved by mixing ammonia with a homogeneous aqueous solution of bismuth nitrate containing excess nitric acid and ammonium germanate. The resulting BGO powder exhibited a peculiar morphology of nanoscale indentations that gave each particle a flower-like shape. The main peak of its photoluminescence (PL) spectrum was almost the same as that observed with commercial high-purity BGO powder, but additional weak luminescence peaks were observed at about 370 and 820 nm that showed good agreement with the PL peaks of BiGeO2(OH)2(NO3) powder. Furthermore, the synthesized BGO powder was confirmed to be a single BGO phase through X-ray diffraction and Rietveld analysis, and the existence on the adsorbed H2O, HNO3, and chemisorbed NO3 were detected through Fourier transform infrared spectroscopy.