Scanning Electron Microscopy (SEM) Investigation of Morphology Changes in the Reduction of Silica Nanoparticles to Elemental Silicon

Abstract

The application of silicon nanoparticles varies from energy storage materials, to drugdelivery, and molecular recognition. Various chemical and physical properties of the Si nanoparticles arise from their morphology. This paper aims to reveal the morphology of Si nanoparticles following magnesiothermic reduction of silica (SiO 2) nanoparticles. Two sets of SiO 2 nanoparticles were used, commercially available NanoXact nanoparticles and laboratorysynthesized Stöber nanoparticles. A Zeiss Sigma VP FEG SEM was used to examine the morphology. Following the magnesiothermic reduction, the nanoparticles were etched with HF. Ten sets of images were taken of both Stöber and NanoXact nanoparticles: 1,2: the SiO 2 nanoparticle starting materials; 3,4: the products after magnesiothermic reduction using NaCl as a heat sink; 5,6: the products after magnesiothermic reduction without NaCl as a heat sink; 7,8: the products after HF etching following magnesiothermic reduction with NaCl; 9,10: the products after the HF etching following magnesiothermic reduction without NaCl. This thesis is about the morphology changes in the reduction of silica nanoparticles to elemental silicon experiment. The experiment was conducted with the aim of achieving morphology preserving, reduced silicon nanoparticles for applications in various branches of science such as medical, materials, and chemistry.