Developing of buffer-precipitation method for lead metaborate (Pb(BO₂)₂ H₂O) nanostructures

Amorphous lead metaborate (Pb(BO₂)₂ H₂O) nanostructures were synthesized by a simpl and cost-effective synthesis method which is based on precipitation of lead ions using boric acid/sodium hydroxide buffer (pH 9.2) in the presence of polyethylene glycol (PEG). Scanning electron microscopy images showed that the average particle size is 30±9 nm and the particle shape is mostly spherical. The chemical formulation of Pb(BO₂)₂ H₂O was confirmed by infrared spectroscopy, inductively coupled plasma and thermal gravimetric analysis (TGA). The percentage of PEG molecules on the particle surface equal to 2.5 % was determined by TGA. Optical reflectance measurement was performed by UV-Vis spectroscopy. Based on the Kubelka-Munk function, it was calculated that the Pb(BO₂)₂ H₂O nanostructures have a direct band gap of 4.6 eV.