Large-scale selective preparation of porous SnO2 3D architectures and their gas-sensing property

Porous SnO2 cubes and rods were obtained by a facile chemical solution route combined with subsequent calcination and an acid-washing process. Techniques of X-ray diffraction, scanning electron microscopy, thermogravimetric-differential thermalgravimetric analysis, transmission electron microscopy, and Brunauer-Emmett-Teller N-2 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 CuSn(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 CuO and porous tetragonal SnO2. The porous SnO2 3D architectures are obtained after the CuO particles are 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 3D architectures were investigated using toluene and formaldehyde as the representative target gases. The porous SnO2 3D architectures exhibit excellent sensing performances due to the high porosity and 3D morphology, which can significantly facilitate gas diffusion and mass transportation in sensing materials. This work further hints that this new facile and economical approach can be extended to synthesize other porous metal oxide materials with a unique morphology or shape.