Preparation And Properties Of Gas Sensor Based On MXene@Au Composites

At present,with the development of the industry that the discharge of waste solid,waste liquid and waste gas also increasing.Different from solid and liquid pollutants could be directly observed,the gas pollutants were colorless and difficult to be directly observed until they are inhaled.With the flexible electronic sensor emerging applications in the Internet of Tings,robotics,health assessment and environmental monitoring,the flexible sensors gained considerable interest.As an effective way for detecting toxic gases,gas sensor have become increasingly important because environment pollutants and the health of human.Among toxic gases,trimethylamine(TMA),is very harmful to human health,such as eye irritation,headaches,breathing difficulty,lung infection and even death.In addition,the concentrations of TMA are markedly depending on the degree of decaying fish and seafood.It is necessary to develop a gas sensor for real-time monitoring of low concentration of TMA to guarantee people’s safety and determine the freshness of seafood.This paper has based on the MXene two-dimensional materials,doping noble metal nanoparticle and compounding MXene@Au with different polymer materials to prepare excellent performance gas sensor.Specific research contents and results are as follows:1.Doping gold nanoparticles in MXene for improves the low conductivity of MXene at room temperature.Then the MXene@Au composite material was dispersed in PVP solution and drip-coated on the finger electrode.After drying,the sensor prepared was a good gas sensor for detecting trimethylamine gas.The gas sensor detection limit was low for trimethylamine gas.The response to 0.5 PPM trimethylamine gas was 27.4% at room temperature and it has linear relationship to trimethylamine gas in the range of 0.5 to 10 ppm TMA gas.The sensor also has fast response and recovery time(response time 17.8 s,recovery time 37 s)and good stability.2.The self-healing hydrogel based on MXene@Au composite was prepared by doping MXene@Au into PVP-tannic acid self-healing hydrogel.Then testing the hydrogel mechanical properties,self-healing properties and gas sensitivity.The results show that the hydrogel sensor not only has certain mechanical properties(fracture stress is 0.12 MPa),but also has good self-healing performance.The healing efficiency was 95.83% in the absence of external stimulation.At the same time,the gas sensitivity test shows that the self-healing hydrogel has a higher response to trimethylamine.The response to 10 ppm trimethylamine at room temperature was 15.03%.The response time and recovery time were 104.2 s and 82.2 s.In the 35-day stability testing this sensor response remained basically stable during and it has a certain linear relation to trimethylamine gas in the range of 1-100 ppm.3.The antifreezing and high strength MXene@Au double network hydrogels which can be used for gas sensing materials were prepared by doping MXene@Au composites in acrylamide and CMC-Na solution.The mechanical performance and gas sensor performance tested show that the MXene@Au hydrogels have excellent mechanical properties this fracture stress was 1.22 MPa and fracture strain was 625%.In addition to the MXene@Au hydrogels has excellent gas sensitive performance,It has a good linear relationship for 0.25-200 ppm trimethylamine gas at room temperature and 5-100 ppm trimethylamine gas at 0 ℃.At the same time,the sensor could apply to monitoring fish freshness,the results show that the hydrogel sensor can quickly detect the freshness of fish in real time.