Mg2Si nanocomposite converted from diatomaceous earth as a potential thermoelectric nanomaterial

With recent literature demonstrating enhancement of the thermoelectric performance of nanoscale materials relative to their corresponding bulk materials, methods to synthesize low-dimensional nanomaterials in large scale at low cost are needed. We demonstrate a method for preparing nanostructured dimagnesium silicide (Mg2Si) thermoelectric materials that are nanocomposites with MgO by the reduction of diatomaceous earth (diatoms) using a gas-displacement solid state reaction with magnesium vapor. The resulting semiconducting Mg2Si preserves the general morphology of the original diatoms and their nanosized grains at least down to the size of 30 nm. This reaction represents a possible method for the production of large quantities of low-cost nanoscale thermoelectric materials with potential for enhanced thermoelectric performance.

Graphical abstractA nanostructured Mg2Si and MgO nanocomposite thermoelectric material is synthesized in the Mg gas-displacement solid state reduction of SiO2 from diatomaceous earth. The resulting semiconducting Mg2Si nanostructures preserve the original diatom morphology, with nanosized grains at least down to the size of 30 nm.Figure optionsDownload full-size imageDownload as PowerPoint slide