Hydrothermal Synthesis of Tin Oxide Nanostructures

Abstract

A concise overview based on research is presented for method development on hydrothermal synthesis tin oxide nanostructures along with the optimization of the operational conditions, with two salts, three salts, and cheap seawater electrolyte as conductor. This method is implemented to the production of porous SnO2 nanostructure for application of gas sensing.

In the past decade, a lot of works have been carried out aiming to develop SnO2 nanostructures due to their various potential applications, especially in the field of gas sensors. Several methods have been used either as top-down or bottom-up approach. One of the most popular methods to fabricate metal oxide nanostructures is a hydrothermal growth. The benefits of this method are the low processing temperature, mildness, simplicity, and the high purity of the final products. This method is also effective in controlling the morphology of metal oxide nanostructures. The optimization of the ideal controlling parameters must be done to obtain metal oxide structures with good properties. The structure of the metal oxides that are formed, and thus their properties are strongly influenced by the synthesize parameters, such as reaction temperature and time, the composition of precursors, solvent nature, the different pH value of the solvent, surfactant additive and the structure of a substrate for constant surface area.

Hydrothermal SnO2 nanostructures have been successfully synthesized by optimizing the reaction temperature of 200 °C and the reaction time of 4-6 hours. The use of a mixture of SnCl2·2H2O and SnSO4·2H2O metal salts with metal seawater electrolyte in growth solution show a more uniform nanorod shape. SnO2 nanorods with the best optic, high values of absorption coefficient and wide bandgap energy of 3.52 eV, have been prepared with up to the highest metal salts seawater electrolytes of good on glass substrates coated with the white electrophoretic layer.