Porous 2D CuO nanosheets for efficient triethylamine detection at low temperature

The freshness of seafood can be judged by detecting the concentration of triethylamine(TEA). In this work, 2D Cu O porous nanosheets(Cu O PNs) were prepared by a graphene oxide template method and their particle sizes were regulated by changing the calcination temperature. Their structure, morphology and gas sensing performances were investigated by various characterization methods. The response(Rg/Ra) of the gas sensor based on Cu O PNs calcined at 700oC was as high as 440-100 ppm TEA at the operating temperature of 40 ℃. The detection limit was as low as 0.25 ppm. In addition, the gas sensor has good selectivity and stability. The excellent TEA sensitivity is mainly resulted from the appropriate particle size and loose porous framework. This work not only paves the way to explore the novel low temperature TEA gas sensors, but also provides deep insight on improving the structure and properties of gas sensitive materials by controlling the calcination temperature.

Preparation and formaldehyde sensitive properties of N-GQDs/SnO2 nanocomposite

Graphene quantum dots(GQDs)have both the properties of graphene and semiconductor quantum dots,and exhibit stronger quantum confinement effect and boundary effect than graphene.In addition,the band gap of GQDs will transform to non-zero from 0 eV of graphene by surface functionalization,which can be dispersed in common solvents and compounded with solid materials.In this work,the SnO2 nanosheets were prepared by hydrothermal method.As the sensitizer,nitrogen-doped graphene quantum dots(N-GQDs)were prepared and composited with SnO2 nanosheets.Sensing performance of pristine SnO2 and N-GQDs/SnO2 were investigated with HCHO as the target gas.The response(Ra/Rg)of0.1%N-GQDs/SnO2 was 256 for 100 ppm HCHO at 60℃,which was about 2.2 times higher than pristine SnO2 nanosheet.In addition,the material also had excellent selectivity and low operation temperature.The high sensitivity of N-GQDs/SnO2 was attributed to the increase of active sites on materials surface and the electrical regulation of N-GQDs.This research is helpful to develop new HCHO gas sensor and expand the application field of GQDs.