Thermal stability of lead sulfide and lead oxide nano-crystalline materials

In this study, nano-crystalline lead sulfide (PbS) and lead oxide (PbO) were synthesized using hassle-free and cost-effective chemical route. Lead oxalate (PbC 2 O 4 ) precursor was thermally decomposed to obtain the nano-crystalline PbO, while PbS nanoparticles were synthesized by microwave irradiation on a mixture of PbC 2 O 4 precursor and sodium thiosulfate. Resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, ultraviolet–visible (UV–Vis) spectrophotometry, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). XRD confirmed the tetragonal structure for PbO and face-centered cubic for PbS with average crystallite sizes varying from 20 to 30 nm for both materials. From UV–Vis spectra, direct band gap energies were calculated to be 2.51 and 2.23 eV for PbO and PbS, respectively. Various decomposition stages during heat treatment of PbO and PbS, as revealed by TGA/DSC, are discussed in detail.