Preparation And Application Of Self-powered Sensor For Detecting Harmful Gas In Livestock And Poultry House

As the pace of modernization in agriculture continues to accelerate,the application of sensor technology will become more widespread and profound.As an important component of agricultural modernization,sensors can not only improve the efficiency and quality of agricultural production and management but also reduce negative impacts such as resource waste and environmental pollution,achieving sustainable and high quality agriculture development.In the development of livestock and poultry farming,resistive gas sensors can be used to monitor harmful gases in livestock and poultry houses in real-time,enabling people to control them within appropriate ranges,ensuring the air quality and animal health.Currently,friction nanogenerators based on frictional electricity and electrostatic induction can effectively utilize external environmental energy,converting clean,renewable energy into electricity,providing a new solution to the power supply problem of gas sensors.This article focuses on the research of self-powered gas sensors for detecting harmful gases in livestock and poultry houses,including the preparation and characterization analysis of MXene-based composite sensitive films,the optimization design of TENG and the preparation of self-powered sensors,and the preparation and application of self-powered gas sensing systems for wind energy collection.The main contents are summarized as follows:（1）Taking harmful gases（NH₃ and H₂S）from livestock and poultry sheds as the research object,NiO and SnO₂ nanoparticles were prepared by hydrothermal method and high-temperature calcination method,respectively.Then,two composite gas-sensitive materials,NiO/MXene and SnO₂/MXene,were prepared by ultrasonic self-assembly method through doping with MXene for detection of NH₃ and H₂S.The successful synthesis of MXene-based metal oxide composite materials was verified by various characterization methods such as SEM,XRD,and XPS.The favorable effects of MXene on the use of NiO and SnO₂ nanoparticles for gas sensing were analyzed.The results showed that due to the unique accordion-like structure of MXene,metal oxide nanoparticles could be attached to the interlayer and surface of MXene,which not only reduced the aggregation behavior between nanoparticles but also provided a larger specific surface area and adsorption sites for gas adsorption on the rough surface structure of the composite material.Moreover,there are many functional groups（-O,-OH,-F）on the surface of MXene,which are conducive to the interaction between the target gas and the sensitive material.（2）A self-powered gas sensor was prepared using a contact-separation type TENG as the energy source.In the preparation of the TENG self-powered unit,PDMS and TPU films were used as the friction layers of the negative and positive electrodes of the TENG.Tests showed that PDMS and TPU have excellent electrical insulation properties and elastic characteristics,which can maintain long-term and stable output of the TENG.In addition,the impact of operating frequency and contact area on the TENG output was compared and analyzed,and a TENG with high output performance and small size was prepared.In terms of gas sensing unit testing,composite sensitive materials were compared and tested for their response to target gases at different gas concentrations at room temperature.The test results showed that the doping of MXene can effectively improve the detection performance of metal oxides for NH₃ and H₂S at room temperature.Gas sensors prepared from the two composite materials showed fast response and recovery time,good reproducibility,selectivity,and long-term stability under high and low concentrations of target gases within the target range.Finally,the sensitive mechanisms of the composite sensitive materials for NH₃ and H₂S were analyzed.（3）Using wind energy inside livestock and poultry houses as an energy source,a tremor-induced triboelectric nanogenerator（TENG）self-powered gas-sensitive sensing system was optimized based on the contact-separation frictional electrification principle.The TENG output performance of MXene/PDMS composite films with different doping ratios as the friction layer was analyzed.The effectiveness of MXene composites in improving TENG output performance was verified,and the influence of parameters such as film size,tremor distance,and wind speed on the output performance of the tremor-induced TENG was analyzed.Subsequently,a rectification and filtering voltage stabilization circuit was designed,and a gas testing system was constructed to prepare and test the gas sensitivity response performance of composite gas-sensitive materials doped with different ratios to two types of harmful gases in livestock and poultry houses.Experimental tests showed that optimizing the doping of gas-sensitive materials significantly improved the response characteristics of self-powered gas sensors,and the optimized gas sensor also had good response/recovery characteristics and repeatability.