Optimizing Crystallite Size of Synthesized PbS Nanoparticles Using Response Surface Methodology

Abstract

Lead sulfide (PbS) nanoparticles are used in gas sensing for which it is necessary to achieve smaller PbS crystallite sizes. However, the operating conditions to produce the minimum size of PbS nanoparticles do not seem to be reported so far. In this light, this article discusses the synthesis of PbS nanoparticles using the Response Surface Methodology (RSM) choosing the face-centered central composite design (FC-CCD) for which a total of 20 (twenty) experiments are required to be conducted. X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) are used for synthesized PbS samples’ characterization. The smallest PbS crystallite size, as reveals from XRD analysis, is 14.11 nm. All samples' FTIR spectra verified the distinctive peaks of PbS phase. PbS nanoparticle formation is visible in the SEM images. A reduced quadratic polynomial model as obtained from the optimization is found to be accurate. An experiment carried out under optimum conditions confirms the model’s validity in obtaining PbS nanoparticles' crystallite size of 15.62 nm (deviation = + 3.24 %). It can be concluded that the methodology demonstrated in this article could can be applied to synthesize PbS nanoparticles with a minimum crystallite size for use as gas sensors.