Design And Synthesis Of Black Phosphorus-based Composites And Research On NO_x Gas Sensitivity

In recent decades,with the rapid development of industry and the increase of industrial exhaust emissions,the concentration of nitrogen oxides?NO_x?is increasing,whice leading to more and more serious air pollution,such as photochemical smog,acid rain and so on.Therefore,it is urgent to develop high sensitivity gas sensors to detect NO_x.Therefore,the research of gas sensing to NO_x detection in air at room temperature has become a hot spot.Black phosphorus?BP?is a new two-dimensional atomic crystal material.Similar to graphene?GS?,the molecular adsorption energy of BP is much larger than that of MoS2and GS,which makes BP have broad application prospects in sensing field.In this study,we used bulk black phosphorus as a raw material.After liquid phase stripping and other processes,we can obtain two-dimensional thin black phosphorus nanosheets,and use this as a base material to construct metal oxide semiconductor Co₃O₄ and precious metal Pt.Co₃O₄@BP-PEI and BP-Pt composites were synthesized from composite materials.The synthesized materials were characterized by XRD,BET,SEM,TEM and XPS.The composition,structure,morphology,specific surface area,metal atomic valence,oxygen species and concentration distribution were studied.In addition,Co₃O₄@BP-PEI and BP-Pt sensor was constructed with as sensitive materials.The selectivity,gas-sensitive response,response time,repeatability and stability of the sensor were studied.The result shows that the Co₃O₄@BP-PEI and BP-Pt composites have good gas-sensing selectivity,high responsiveness and fast response to NO_x at room temperature,which fabricated by using two-dimensional thin-layer BP nanosheets as matrix.Especially the Co₃O₄@BP-PEI sensor has good repeatability and stability.And the lower detection limit reached 10 ppb.The results of this study expand the application scope of black phosphorus based nanocomposites.And the synthesized nanocomposites with high dispersion and controllable size have good sensing properties towards NO_x gas at room temperature,which have a wide range of development and application prospects.