Solid-State Method Synthesis of SnO2-Decorated g-C3N4 Nanocomposites with Enhanced Gas-Sensing Property to Ethanol

Abstract

SnO₂/graphitic carbon nitride (g-C₃N₄) composites were synthesized via a facile solid-state method by using SnCl₄·5H₂O and urea as the precursor. The structure and morphology of the as-synthesized composites were characterized by the techniques of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), thermogravimetry-differential thermal analysis (TG-DTA), X-ray photoelectron spectroscopy (XPS), and N₂ sorption. The results indicated that the composites possessed a two-dimensional (2-D) structure, and the SnO₂ nanoparticles were highly dispersed on the surface of the g-C₃N₄ nanosheets. The gas-sensing performance of the samples to ethanol was tested, and the SnO₂/g-C₃N₄ nanocomposite-based sensor exhibited admirable properties. The response value (Ra/Rg) of the SnO₂/g-C₃N₄ nanocomposite with 10 wt % 2-D g-C₃N₄ content-based sensor to 500 ppm of ethanol was 550 at 300 °C. However, the response value of pure SnO₂ was only 320. The high surface area of SnO₂/g-C₃N₄-10 (140 m²·g^-1) and the interaction between 2-D g-C₃N₄ and SnO₂ could strongly affect the gas-sensing property.