Preparation of porous SnO2 microcubes and their enhanced gas-sensing property

Porous SnO2 microcubes were obtained through a facile chemical solution route with subsequent calcination and acid-washing process. Their structures and morphology evolution were comprehensively characterized via X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric–differential thermal analysis, and Brunauer–Emmett–Teller N2 adsorption–desorption analyses. The process of inducing porosity starts with a crystalline single-phase MnSn(OH)6 precursor formed by the co-precipitation of the metal ions from the aqueous solution. Thermal decomposition of the precursors leads to an intimate mixture of Mn3O4 and porous tetragonal SnO2. The SnO2 microcubes are obtained after a hydrothermal acid-washing process. A decomposition–aggregation–dissolution process is proposed to demonstrate the formation of such special structure. Furthermore, the gas-sensing properties of the as-prepared porous SnO2 microcubes were investigated in toxic volatile organic compounds, such as formaldehyde, ethanol, benzene, methanol, acetone, and toluene. The enhanced sensing performance of porous SnO2 microcubes was demonstrated. The detection limits of formaldehyde and ethanol were approximately 0.09 and 0.12 ppm (signal-to-noise ratio, S/N = 3), respectively, which substantially benefitted from their unique porous structure and large surface area.