Abstract
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)@SnO2 nanofiber/nanosheets (NF/NSs) nanocomposites. Hierarchical SnO2 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@SnO2 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@SnO2 NF/NSs nanocomposites not only exhibited the highest sensitivity value (Ra/Rg = 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 SnO2 NF/NSs (Ra/Rg = 64 to 100 ppm). GO@SnO2 NF/NSs nanocomposites showed lower detection limit down to 0.25 ppm HCHO and excellent selectivity against interfering gases (ethanol (C2H5OH), acetone (CH3COCH3), methanol (CH3OH), ammonia (NH3), methylbenzene (C7H8), benzene (C6H6) and water (H2O)). 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 SnO2 NF/NSs and GO nanosheets network.
Highlights
HCHO is a colorless gas with pungent smell, which was considered as one of the most serious indoor air pollutants [1]
In order to prepare a new gas sensor with high sensing performance, low operation temperature and excellent selectivity, the combination of graphene and metal oxide semiconductors is a new strategy to enhance sensing performance compared to pure sensing materials [16]
We reported an excellent HCHO gas sensor based on 3D hierarchical SnO2 NF/NSs coated by the graphene oxide (GO) nanosheets
Summary
HCHO is a colorless gas with pungent smell, which was considered as one of the most serious indoor air pollutants [1]. Due to its unique physical and chemical properties, many efforts have been carried out on the application of graphene as sensing elements [12] These advantages, including its high conductivity, large surface area and low electrical noise, make it a promising platform for preparing new sensors [13,14,15]. In order to prepare a new gas sensor with high sensing performance, low operation temperature and excellent selectivity, the combination of graphene and metal oxide semiconductors is a new strategy to enhance sensing performance compared to pure sensing materials [16]. Guo et al have demonstrated excellent acetone sensors by using the electrospun rGO/Fe2 O3 NFs as a sensing material [20] These sensors based on nanocomposites showed low sensitivity, higher operation temperature and poor selectivity. The sensing mechanism of GO@SnO2 NF/NSs and the role of GO were discussed
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