【作者】 刘英；

【导师】 郭影；

【作者基本信息】 北京化工大学 ， 化学， 2024， 硕士

【摘要】 进入二十世纪以来,人们开始越来越多的关注能源损耗与环境污染问题,为了实现社会的可持续发展,构建绿色安全的生活环境,我们需要对有毒有害气体进行监测。由于成本低、简便易携,气体传感器在人类的生产生活中得到了广泛的应用。本文的主要工作是:以Zn₂SnO₄金属氧化物为研究对象,通过与Ti₃C₂T_xMXene复合以及紫外光激发的手段,提高了Zn₂SnO₄金属氧化物的灵敏度,降低了它的最佳工作温度。主要研究内容如下:1.采用简单的水热合成法获得了纳米粒子、八面体和花状结构三种形貌的Zn₂SnO₄,通过调控Ti₃C₂T_xMXene的添加量,将两者加入到乙醇和去离子水的混合溶液中,复合搅拌烘干后,置于马弗炉中以500^oC原位焙烧3 h,获得了三组不同Zn₂SnO₄形貌的Zn₂SnO₄/TiO₂/Ti₃C₂T_x复合材料。根据XRD、SEM、mapping、XPS、BET和固体紫外等表征测试,分析了不同Zn₂SnO₄形貌复合材料的晶体结构、元素组成和形貌特征。在紫外光激发下,纳米粒子形貌的Zn₂SnO₄/TiO₂/Ti₃C₂T_x复合材料对正己醇的气敏性能相比较八面体和花状结构最佳。其中Ti₃C₂T_xMXene所占比例为4%的样品气敏性能最好,对100 ppm正己醇气体的响应灵敏度可达到68.1,比自然光测试条件下的响应提高了3倍,并且工作温度也从300^oC降低到了245^oC,稳定性和选择性较好。在紫外光激发下,复合材料气敏性能的提高主要有两个原因,分别是材料复合后较大的比表面积以及内部形成了氧空位。紫外光激发是提升气体传感器性能并且降低金属氧化物材料工作温度的有效手段。2.采用简单的水热合成法获得了Zn₂SnO₄/ZnO/SnO₂复合材料,通过控制Ti₃C₂T_xMXene的添加量,将一定量的Zn₂SnO₄/ZnO/SnO₂与不同量的Ti₃C₂T_xMXene加入到乙醇和去离子水的混合溶液中,复合搅拌烘干后,制备了Zn₂SnO₄/ZnO/SnO₂/Ti₃C₂T_x复合材料。用XRD、SEM、mapping、XPS、BET和固体紫外对材料的晶体结构和形貌特征进行了表征。相比较自然光条件,在紫外光激发下,Zn₂SnO₄/ZnO/SnO₂/Ti₃C₂T_x复合材料对乙醇的响应性能更好,工作温度更低。其中Ti₃C₂T_xMXene添加量为11%的复合材料气敏性能最好,对100 ppm乙醇的灵敏度响应为36,是自然光条件下的2倍,同时响应时间和恢复时间较短,稳定性和选择性较好。在紫外光激发下,复合材料较好的气敏响应性能主要有两个原因,分别是材料复合后较大的比表面积以及内部形成的p-n异质结。紫外光激发气体传感器对于提升材料的气敏性能、降低材料的工作温度、节约投入成本都具有良好的作用,未来仍然有着广阔的发展前景。更多还原

【Abstract】 Since the 20th century,people have begun to pay more and more attention to the problem of energy loss and environmental pollution,in order to realize the sustainable development of society and build a green and safe living environment,we need to monitor toxic and harmful gases.Due to the low cost,simplicity and portability,gas sensors have been widely used in human production and life.The main work of this paper is that we have improved the sensitivity of Zn₂SnO₄metal oxide and reduced its optimum operating temperature by means of complexation with Ti₃C₂T_xMXene and UV excitation.The main research contents are as follows:1.Three morphologies of Zn₂SnO₄,nanoparticles,octahedra and flower-like structure were obtained by simple hydrothermal synthesis.by regulating the addition amount of Ti₃C₂T_xMXene,both of them were added to a mixed solution of ethanol and deionised water,compounded and stirred and dried,and then placed in a muffle furnace for 3 h with in situ roasting at 500^oC,three groups of different Zn₂SnO₄morphologies were obtained Zn₂SnO₄/TiO₂/Ti₃C₂T_xcomposites.The crystal structures,elemental compositions and morphological features of the composites with different Zn₂SnO₄morphologies were analysed based on characterization tests such as XRD,SEM,mapping,XPS,BET and solid-state UV.The gas-sensitive sensing performance of the composites for hexanol gas was investigated under UV excitation and natural light conditions,respectively.It was found that the nanoparticle morphology of Zn₂SnO₄/TiO₂/Ti₃C₂T_xcomposites had the best gas sensing performance under UV excitation compared to the octahedral and flower-like structures.Among them,the sample with 4%of Ti₃C₂T_xMXene has the best gas-sensitive performance,and the response sensitivity to 100 ppm hexanol gas can reach 68.1,which is three times higher than that of the response under the natural light test condition,and the operating temperature is also reduced from 300^oC to 245^oC with better stability and selectivity.There are two main reasons for the improvement of the gas-sensitive performance of the composites under UV excitation,which are the larger specific surface area of the composite material and the formation of oxygen vacancies inside.UV excitation is an effective means to enhance the performance of gas sensors and reduce the operating temperature of metal oxide materials.2.We obtained Zn₂SnO₄/ZnO/SnO₂composites by a simple hydrothermal synthesis method,and by controlling the addition amount of Ti₃C₂T_xMXene,Zn₂SnO₄/ZnO/SnO₂and Ti₃C₂T_xMXene were successfully prepared with high specific surface area by stirring and drying them in a mixed solution of ethanol and deionized water.Zn₂SnO₄/ZnO/SnO₂/Ti₃C₂T_xcomposites.The crystal structure and morphological features of the samples were characterized by XRD,SEM,mapping,XPS,BET and solid-state UV.The gas-sensitive sensing performance of the composites for ethanol gas was tested under UV excitation and natural light conditions,respectively.The results show that the Zn₂SnO₄/ZnO/SnO₂/Ti₃C₂T_xcomposites have better response performance under UV excitation and lower operating temperature compared to natural light conditions.Among them,the composite with Ti₃C₂T_xMXene addition of 11%has the best gas-sensitive performance,with a response sensitivity of 36 to 100 ppm ethanol,which is twice as much as that under natural light conditions,as well as a shorter response time and recovery time,and higher stability and selectivity.There are two main reasons for the better gas-sensitive response performance of the composites under UV excitation,which are the larger specific surface area of the materials after composite and the p-n heterojunction formed inside.The excited gas sensors are good for improving the gas-sensitive performance of the materials,lowering the operating temperature of the materials,and saving the input cost,and still have a broad development prospect in the future.更多还原