Influence of mechanochemical and microwave treatment of tin dioxide on porous structure and gas-sensitive properties of SnO2-based sensor nanomaterials

Microwave and mechanochemical treatments were used to obtain mesoporous or meso-macroporous structure of tin nanomaterials based on tin dioxide, including with cobalt additive. Samples modified using such techniques have been studied via XRD, TEM, XPS methods, and nitrogen adsorption/desorption. It has been established that calcination of modified samples at 450–620 °C results in formation of well-crystallized structure of cassiterite. Average particle and crystallite size which calculated using Sherrer formula and TEM data are 5–10 and 9–18 nm, respectively. The sample after microwave treatment has the most thermostable porous structure: the value of specific surface area is maximal for this sample after annealing at 620 °C. Therefore, microwave treatment of wet tin dioxide gel turned out to be the most promising for creating more sensitive semiconductor sensors to hydrogen in the range of its concentrations in air of 40–1000 ppm. In particular, Co-containing sensors based on microwave-modified tin dioxide have the highest sensitivity to hydrogen.