The α-Fe2O3/g-C3N4 heterostructural nanocomposites with enhanced ethanol gas sensing performance

• The α-Fe2O3/g-C3N4 heterostructures were successfully synthesized.
• The heterostructures demonstrate a excellent gas sensing performance.
• The heterostructure accelerates electron transfer and improves the gas sensing response.

The α-Fe2O3/g-C3N4 nanocomposites were synthesized by a hydrothermal and pyrolysis method. The structure and morphology of the nanocomposites were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques, which indicates porous α-Fe2O3 nanotubes wrapped by lamellar g-C3N4 structure. Due to the formation of heterojunctions, the α-Fe2O3/g-C3N4 nanocomposites demonstrate a better gas sensing performance than the pure α-Fe2O3 and g-C3N4. The α-Fe2O3/g-C3N4 heterojunctional composites with g-C3N4 60% weight present a maximum gas-sensing response of 7.76 toward 100 ppm ethanol at the optimum operating temperature of 340 °C, which is about 3 and 7 times higher than that of the pure α-Fe2O3 porous nanotubes and pure g-C3N4 nanopowders, respectively. Furthermore, the α-Fe2O3/g-C3N4 nanocomposites exhibit excellent selectivity to ethanol gas, faster response and recovery time than those of the pure α-Fe2O3 porous nanotubes and pure g-C3N4 powders. The possible reason for the enhanced sensing performance obtained from the α-Fe2O3/g-C3N4 nanocomposites is attributed to the porous α-Fe2O3 nanotubes wrapped by lamellar g-C3N4 nanostructures and the formation of heterojunction. The findings reported in this study will be useful to the design and construction of metal oxide nanostructures based heterojunctional structures with enhanced gas sensing performance.