High-performance carbon monoxide gas sensor based on palladium/tin oxide/porous graphitic carbon nitride nanocomposite

The palladium (Pd)/tin oxide (SnO2)/porous graphitic carbon nitride (g-C3N4) nanocomposites with different Pd and g-C3N4 contents were synthesized by a facile hydrothermal route and their applications as efficient carbon monoxide (CO) gas sensors were investigated. These nanocomposites were characterized in detail by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), micrograph techniques (FESEM and TEM), and energy dispersive X-ray spectroscopy (EDS), in order to evaluate their structural and morphological properties. On the basis of the FESEM and TEM analysis, two-dimensional porous g-C3N4 nanosheets provided a large surface area suitable for growth of SnO2 nanoparticles and formation of a heterogeneous nanocomposite. Among different weight ratios of the components of Pd/SnO2/g-C3N4 nanocomposites, 5%Pd/SnO2/5%g-C3N4 exhibited excellent CO sensing characteristics such as high response, short response/recovery times, good selectivity and stability at lower operating temperature of 125 °C. The outstanding gas sensing performance of these nanocomposites could be attributed to the high surface area of porous g-C3N4, the strong spillover effect of Pd nanoparticles as well as the formation of g-C3N4/SnO2 heterojunction. [Display omitted] •Hydrothermal method was used to prepare Pd/SnO2/porous g-C3N4 nanocomposites.•Porous g-C3N4 caused nanosize SnO2 growth and heterogeneous nanocomposite creation.•Influence of the amounts of both Pd and g-C3N4 on features of CO sensor was tested.•Response, dynamic range and selectivity were great for 5%Pd/SnO2/5%g-C3N4 at 125 °C.•Spillover effect of Pd and heterojunction design enhanced sensitivity at 125 °C.