Preparation of porous flower-like SnO₂ micro/nano structures and their enhanced gas sensing property

Porous flower-like tin oxide (SnO₂) structures were obtained using a hydrothermal method combined with a subsequent calcination and acid-washing process. The morphologies and crystal structures of the products were characterized by field emission scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller N₂ adsorption-desorption analyses. The process of inducing porosity begins with a flower-like nickel tin sulfur precursor. Thermal decomposition of this flower-like nickel tin sulfur precursor leads to an intimate mixture of porous flower-like NiO/SnO₂ hybrids. Porous SnO₂ flowers were obtained after removing the cubic phase NiO by an acid-washing process. Furthermore, the gas sensing properties of the as-prepared porous SnO₂ flowers to VOCs, such as ethanol, formaldehyde, benzene, toluene, and acetone, were investigated. The porous SnO₂ flowers showed a good response and reversibility to some organic vapors, such as ethanol and formaldehyde. The sensing responses to 100 ppm ethanol and formaldehyde were 42.4 and 24.8, respectively. The sensors also exhibited a good response to benzene, toluene, methanol, and 2-propanol. The relationship between the gas-sensing properties and the microstructure of the as-prepared flower-like SnO₂ structures was also examined. - Highlights: • Flower-like nickel tin sulfur structures were synthesized by hydrothermal method. • Porous SnO₂ microflowers were obtained by treatment of the precursor. • Porous SnO₂ microflowers exhibited excellent sensing properties to some gases. • Excellent gas-sensing properties were attributed to the special 3D structures.