A Simple Dip-Coating Method of SnO2-NiO Composite Thin Film on a Ceramic Tube Substrate for Methanol Sensing

In this work, SnO2-NiO composite thin film was successfully grown on a ceramic tube substrate directly by a simple dip-coating method combined with annealing. Characterization analysis demonstrates that uniform SnO2 film consists of a great number of nanospheres and NiO grows on SnO2 as an agglomerated block. In comparison to the pure SnO2 sample, the SnO2-NiO composite thin films gas sensor exhibits superior methanol sensing properties at 225 °C. The gas response to 10 ppm methanol reached 15.12 and the response and recovery times were 8 s and 7 s, respectively. The excellent selectivity and recovery rate are explained by the unique properties of the NiO semiconductor and the higher sensor response is attributed to the pivotal heterojunction effect.

Nanomaterial Preparations by Microwave-Assisted Solution Combustion Method and Material Properties of SnO2 Powder - A Status Review

A nanocrystalline tin oxide (SnO2) powders have been prepared by a simple, low-temperature initiated, self-propagating and gas producing by microwave-assisted solution combustion process. The effects of temperature on crystalline phase formation and particle size of nanocrystalline SnO2 and its structure have been investigated. It is observed that heat-treated upto 800°C shows tetragonal phase SnO2. It was observed that the average crystallite size of the annealed SnO2 samples is in the range 9 - 43 nm through controlled heat treatment process. The crystal density of the as-prepared powder is 5.850g cm-3 where as the bulk density is 6.998 g cm−3. The microstructure and morphology were studied by scanning electron microscope (SEM) and HRTEM it is interesting to note that as-prepared SnO2 sample are almost spherical in shape and average agglomerate crystal size of 0.2 – 0.4 μm with increase in calcination temperature, the samples become better morphology than the as-prepared sample. The crystallographic parameters were refined by XRD pattern and Rietveld refinement using TOPAS-3 and Diamond software was used to construct the structural parameters.