Highly selective NO2 chemiresistive gas sensor based on hierarchical In2O3 microflowers grown on clinoptilolite substrates

Abstract

Hierarchical In2O3 microflowers (HIMF) were prepared via a simple one-step hydrothermal method on the surface of the clinoptilolite substrate (CS). Structural characterizations were investigated by various techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectric spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). The results demonstrated that the HIMF were comprised of abundant ultrathin two-dimensional nanosheets with a width of about 500 nm and the thickness of approximately 20 nm. The high-yield HIMF with a hexagonal phase were loose and uniformly distributed on the surface of the CS. The CS accompanied with the HIMF was made into a gas sensor to test NO2 sensing properties. It indicated that the gas sensor exhibited excellent NO2 sensing performance of low operating temperature, fast response, high selectivity and good reversibility. The outstanding NO2 sensing properties of the HIMF could be ascribed to its unique hierarchical structure and the synergistic effect of the CS. The possible formation process and sensing mechanism of the HIMF were proposed. The results show a potential prospect for using the natural porous mineral as the substrate to synthesize high-performance sensing material.