Effective VOCs gas sensor based on porous SnO2 microcubes prepared via spontaneous phase segregation

Porous SnO2 microcubes were obtained by a facile chemical solution route combined with subsequent calcination and acid-washing process. Spontaneous phase segregation yields such a special porous structure. Several techniques, such as X-ray diffraction, scanning electron microscopy, thermogravimetric–differential thermalgravimetric analysis, transmission electron microscopy, and Brunauer–Emmett–Teller N2 adsorption–desorption analyses, were used to characterize the structure and morphology of the products. The process of inducing porosity starts with a crystalline single-phase hydroxide precursor CoSn(OH)6 formed by the co-precipitation of the metal ions from aqueous solution. Thermal decomposition of the precursors leads to an intimate mixture of Co3O4 and porous tetragonal SnO2. The porous SnO2 microcubes are obtained after the Co3O4 phase is removed by acid-washing. A decomposition–aggregation–dissolution process is proposed to demonstrate the formation of such a special structure. Furthermore, gas sensing properties of the as-prepared porous SnO2 microcubes were investigated to VOCs such as benzene, toluene, acetone, and ethanol. The results have showed that the porous SnO2 microcubes exhibit excellent sensing performances towards toluene and benzene, indicating that the special porous SnO2 structures are highly promising for the applications of gas sensors.