Graphene Oxide@3D Hierarchical SnO(2) Nanofiber/Nanosheets Nanocomposites for Highly Sensitive and Low-Temperature Formaldehyde Detection

In this work, we reported a formaldehyde (HCHO) gas sensor with highly sensitive and selective gas-sensing performance at low operating temperature based on graphene oxide (GO)@SnO(2) nanofiber/nanosheets (NF/NSs) nanocomposites. Hierarchical SnO(2) NF/NSs coated with GO nanosheets showed enhanced sensing performance for HCHO gas, especially at low operating temperature. A series of characterization methods, including X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) were used to characterize their microstructures, morphologies, compositions, surface areas and so on. The sensing performance of GO@SnO(2) NF/NSs nanocomposites was optimized by adjusting the loading amount of GO ranging from 0.25% to 1.25%. The results showed the optimum loading amount of 1% GO in GO@SnO(2) NF/NSs nanocomposites not only exhibited the highest sensitivity value (R(a)/R(g) = 280 to 100 ppm HCHO gas) but also lowered the optimum operation temperature from 120 °C to 60 °C. The response value was about 4.5 times higher than that of pure hierarchical SnO(2) NF/NSs (R(a)/R(g) = 64 to 100 ppm). GO@SnO(2) NF/NSs nanocomposites showed lower detection limit down to 0.25 ppm HCHO and excellent selectivity against interfering gases (ethanol (C(2)H(5)OH), acetone (CH(3)COCH(3)), methanol (CH(3)OH), ammonia (NH(3)), methylbenzene (C(7)H(8)), benzene (C(6)H(6)) and water (H(2)O)). The enhanced sensing performance for HCHO was mainly ascribed to the high specific surface area, suitable electron transfer channels and the synergistic effect of the SnO(2) NF/NSs and GO nanosheets network.