Study Of Preparation Of CNTs/Pd Nanoparticle Composite Structure And Construction Of The Hydrogen Sensor

As an environmentally friendly,clean and renewable energy source,hydrogen makes itself be fulled use in all important areas.However,during the use of hydrogen,it is prone to leak,which causes explosions with unpredictable adverse consequences.Therefore,it is necessary to detect hydrogen on real-time and effective for the safety of property and life.The traditional hydrogen sensors are mostly based on hard substrates?ordinary glass,quartz glass,silicon wafers,etc.?.With the development of nanotechnology,highly sensitive,low-cost,portable,and low-power gas sensors based on nanomaterials?CNTs?carbon nanotubes?,carbon nanowires,carbon nanofibers,and carbon nanoparticles?have been attract attention by people.Among them,CNTs,as one-dimensional nanomaterials,can adsorb and store gas molecules more easily because of their hollow structure with high specific surface area.Therefore,CNTs can be used to prepare flexible hydrogen sensors and can be integrated into various smart wearable electronic devices.This dissertation mainly studies the preparation of CNTs/Pd nanoparticle composite structure and the construction of hydrogen sensor.The Pd nanoparticles were modified to the surface of CNTs by physical deposition?magnetron sputtering?and chemical reduction methods to form CNTs/Pd nanoparticle composite structures.And it's for different flexible substrates to build the ideal flexible hydrogen sensor.Firstly,the formation of CNTs thin films on the surface of polydimethlsiloxane?PDMS?flexible substrates is studied.It mainly including the dispersion of CNTs,The preparation of PDMS flexible substrates and the formation of dense CNTs networks on the PDMS surface by spray coating.In order to remove the SDS?surfactant?remaining on the surface of the CNTs,it's washed with deionized water and HNO₃ successively.The CNTs films were tested by UV-Vis spectrophotometer and Raman spectroscopy to verify the effects of deionized water and HNO₃ on CNTs films from the side.Secondly,in order to better study the evolution of Pd film on the surface of PDMS flexible substrate,a series of Pd films with different thicknesses were sputtered on the surface of common glass and PDMS,and hydrogen sensitivity test was performed.It was finally found that when the Pd film of 2.25nm is sputtered on the PDMS flexible substrate surface,the deposited Pd nanoparticles are discontinuous.Next,in order to prepare a flexible hydrogen sensor of PDMS/CNTs/Pd composite structure,the Pd film of 2.25nm was sputtered on the CNTs film formed on the surface of the PDMS flexible substrate.It not only ensures that the hydrogen sensor based on this structure type is flexible,but also has good hydrogen-sensitive properties.Finally,a flexible,porous,and collapsible PTFE?polytetrafluoroethylene?filter was used as the substrate.Pd NPs were modified onto the surface of CNTs by liquid-phase chemical reduction and magnetron sputtering,and then CNTs modified with PdNPs is transferred to the surface of PTFE.A flexible hydrogen gas sensor with a PTFE membrane/CNTs/Pd composite structure was fabricated on the surface.