【作者】 孙娜；

【导师】 刘波； 景强；

【作者基本信息】 山东理工大学 ， 材料与化工（专业学位）， 2023， 硕士

【摘要】 工业的迅速发展以及人类生活质量的提升会带来一系列的环境污染问题,自然以及工业产生的NO₂和H₂S气体也对人类危害巨大。其中NO₂主要来自于生活中一些常见的高温燃烧过程,吸入NO₂会对人体的呼吸道造成损害,当暴露在平均浓度为82 ppb NO₂一小时以上时就会直接危害生命安全。H₂S是一种无色但具有强烈气味的有毒气体,它和人类生活密切相关,低浓度的H₂S就会诱发一系列的神经系统和呼吸系统疾病。而气体传感器依靠自身的众多优点被众多研究者探索、发掘而用来实时监测一些有毒有害气体,为我们的健康保驾护航。本文围绕二元金属氧化物氧化锌（ZnO）和三元金属氧化物钼酸铋（Bi₂MoO₆）两种n型金属氧化物半导体（MetalOxide Semiconductors,MOSs）材料进行研究,通过掺杂贵金属、构建异质结构来提升本体材料对于目标气体的灵敏度而成功合成了具有优异传感性能的NO₂气体传感器和H₂S气体传感器。具体的研究工作如下:（1）本文的第一个工作是基于静电纺丝法合成贵金属Rh掺杂ZnO纳米纤维,通过XRD、SEM、XPS等手段从晶体结构以及表面形貌均证实了Rh掺杂ZnO纳米纤维的成功合成,且该传感器的可探测下限为50 ppb的NO₂,这足以满足人类的日常所需。通过不同摩尔比的Rh掺杂进ZnO的晶格中作比较发现掺杂摩尔比为1:100时,在150℃的最佳工作温度下该传感器对NO₂的传感性能最佳,其对10 ppm和50ppb的NO₂响应分别为36.17和1.04,且该传感器拥有良好的气体选择性、可重复性和长期稳定性。掺入Rh后气敏性能提升归因于材料表面丰富的氧空位缺陷以及Rh对H₂O和NO₂的催化活性。（2）第二个工作即采用溶胶-凝胶法合成Bi₂MoO₆-CuO异质结构薄膜,XRD结果表明Bi₂MoO₆与CuO均存在于样品中,且TEM明显发现Bi₂MoO₆与CuO异质结构的形成。通过气敏测试结果发现Bi₂MoO₆-CuO复合材料在70℃的最佳工作温度下对H₂S的灵敏度最高且探测下限可达100 ppb,该传感器对1 ppm和100 ppb的H₂S响应分别为7.96和1.12。除此之外,经过一系列的浓度梯度测试、重复性测试、气体选择性测试均证明了该传感器对H₂S气体良好的传感性能,其气敏性能的提升归因于Bi₂MoO₆-CuO异质结构的成功构建。更多还原

【Abstract】 The rapid development of industry and the improvement of human quality of life will bring a series of environmental pollution problems,natural and industrial NO₂and H₂S gases are also very harmful to humans.NO₂mainly comes from some common high temperature combustion process in life,inhalation of NO₂will cause damage to the human respiratory tract,when exposed to an average concentration of 82 ppb NO₂for more than one hour will be directly endangered life safety.H₂S is a colorless but strong-smelling toxic gas,which is closely related to human life,and low concentrations of H₂S can induce a series of neurological and Respiratory system diseases.The gas sensor relies on its many advantages and has been explored and discovered by many researchers and used to monitor some toxic and harmful gases in real time to protect our health.This paper focuses on two n-type oxide semiconductor materials,binary metal oxide zinc oxide（ZnO）and ternary metal oxide bismuth molybdate（Bi₂MoO₆）.We have successfully synthesized NO₂and H₂S gas sensors with excellent sensing performance by doping precious metals and building heterostructures to enhance the sensitivity of the native materials to the target gases.The specific research work is as follows:（1）The first work in this paper is based on the synthesis of noble metal Rh-doped ZnO nanofibers by electrostatic spinning method.The successful synthesis of Rh-doped ZnO nanofibers was confirmed by XRD,SEM and XPS in terms of crystal structure as well as surface morphology,and the detectable lower limit of the sensor is 50 ppb of NO₂,which is sufficient for the daily needs of human beings.By comparing the different molar ratios of Rh doped into the lattice of ZnO,it was founded that the sensor achieved the best sensing performance for NO₂at the optimum operating temperature of 150℃with the response of36.17 and 1.04 for 10 ppm and 50 ppb NO₂,respectively,and the sensor has good gas selectivity,repeatability and long-term stability.The improved gas-sensitive performance after Rh doping is attributed to the abundant oxygen vacancy defects on the material surface and the catalytic activity of Rh for H₂O and NO₂.（2）The second work,namely,the synthesis of Bi₂MoO₆-CuO heterostructure films by sol-gel method,XRD results showed that both Bi₂MoO₆and CuO were present in the samples,and TEM obviously found the formation of Bi₂MoO₆and CuO heterostructures.The results of gas-sensitive tests showed that the Bi₂MoO₆-CuO composite had the highest sensitivity to H₂S at the optimum operating temperature of 70°C and the lower detection limit was up to 100 ppb.The response of the sensor to H₂S at 1 ppm and 100 ppb is 7.96 and 1.12 respectively.In addition,a series of concentration gradient tests,repeatability tests and gas selectivity tests have demonstrated the good sensing performance of the sensor for H₂S gas,the improved gas-sensitive performance is attributed to the successful construction of Bi₂MoO₆-CuO heterostructures.更多还原