TiO_2基氧化物半导体氧敏传感器的研究开发进展

综合介绍 TiO2基氧化物半导体氧敏传感器的研究发展历史和 TiO2材料的特性,比较了各 种氧敏机理、制备方法、传感器的氧敏特性,就制备方法－材料微观结构－氧敏性能关系中的几 个重要问题,进行了深入的探讨,并对今后的研究开发与产业化,结合本课题组的研究工作,提出 了几点建议。     

TiO2—Nb2O5复合氧化物氧敏响应特性及结构研究

将ＴｉＯ２和Ｎｂ２Ｏ５氧化物氧敏材料复合，研究氧敏响应特性及其与环境温度，气流转换频率的关系，并指出采样方法对响应时间的影响。在无贵金属催化条件下，烧结型复合氧敏材料的响应时间约为６０ｍｓ。对材料的结构与响应机理进行了分析与初步探讨。     

w^6＋掺杂TiO2纳米材料化学吸附与氧敏特性研究

以TiCl3为钛源，采用溶胶-凝胶法制备W^6＋掺杂TiO2纳米粉体，经400℃低温烧结1h，即可得到以金红石相为主相的TiO2基氧敏材料。采用XRD、BET、TPD等手段对其进行表征、分析，结果表明W^6＋掺杂有利于形成以金红石相为主相的晶体结构，使样品的晶粒尺寸减小、比表面积增加，使氧敏特性提高，其中12％（摩尔分数）W^6＋／TiO2的氧气化学吸附量最大，敏感层表面对氧气的活性最高；在低工作条件（115℃）及1×10^-4氧气下，W^6＋掺杂TiO2的厚膜型气敏元件氧敏特性得以明显提高，且掺杂12％（摩尔分数）W^6＋灵敏度最佳（S=16．5）。     

TiO2基陶湿敏元件的研究和发展

ＴｉＯ２基湿敏陶瓷是一类十分重要的湿敏陶瓷,应用十分广泛。本文综述了ＴｉＯ２基陶瓷湿敏元件的研究和发展,重要介绍了７种ＴｉＯ２基陶瓷湿敏元件的材料配方、制备工艺、湿敏性能及研究进展。     

新型氧化物半导体气敏传感器的研究进展

空气质量日益恶化问题引起了人们的重视.为了监控空气质量,研究者开发了很多种类的气敏传感器,其中氧化物半导体气敏传感器具有灵敏度高、制造成本低和信号测量手段简单等优点,成为了目前的主流产品.综述了该类型新型传感器的研究进展,介绍了其气敏机理、结构和制作方法,并概述了其存在的问题及今后的发展趋势.     

氧化物半导体气敏传感器的改性研究进展

氧化物半导体气敏传感器具有灵敏度高、制造成本低、信号测量手段简单、使用方便等优点,在有毒有害气体实时监测方面极具应用潜力。综述了新型氧化物半导体气敏感器改性的研究进展、存在的问题及发展趋势。     

氧化物半导体丙酮气敏传感器材料研究与应用

低浓度丙酮气体的检测在监测工业生产、食品质量、畜牧业和疾病等中有重要的作用.综述了近年来氧化物半导体丙酮气敏传感器材料的研究进展,并对传感器材料的形态、制备方法、敏感机理及存在的问题进行了分析,指出了发展方向.     

碳纳米管及其掺杂氧化物半导体气敏传感器

碳纳米管气敏传感器以其工作温度低和最低检出限较低等优点而备受关注,而碳纳米管掺杂氧化物半导体气敏传感器兼备了氧化物半导体气敏传感器和碳纳米管气敏传感器二者的优点,具有灵敏度较高、最低检出限低和工作温度低等特性。综述了这两类传感器的研究进展,介绍了其气敏机理,并对相应存在的问题及今后的发展趋势进行了概述。     

纳米金红石相TiO2块体的介电特性研究

在大气和真空条件下,对纳米金红石相TiO2块体进行介电频谱测试.发现样品在大气中的相对介电常数比其在真空中的数值高102～103倍;大气中介电损耗高于其在真空中的数值,大气中频率约在3 kHz时出现损耗最小值,真空中介电损耗则随频率增加而单调减小.分析认为纳米金红石相TiO2介电常数异常是由材料界面中的缺陷和悬键所引起的.在大气中,纳米金红石TiO2的介电损耗以极化损耗(电偶极矩转向极化和离子弛豫极化)为主,而在真空中则以电导损耗为主.     

烟道用ZrO2氧敏传感器测氧的仪表化方程

本文提出一个新的烟道氧敏传感器测氧的仪表化方程，并给出方程中两个重要参数的标定方法。实测结果表明，用该方程可实现恒温测氧，且快速准确、方便实用，测量误差不大于０．０５％。     

Characterization of a nanosized TiO2 gas sensor

Thin films were obtained by r.f. reactive sputtering from a Ti_.1W_.9 target onto a Si substrate followed by annealing in air at 800 °C. The thermal treatment results in a nanosized TiO₂ thin film with high surface-to-volume ratio. The nanosized structure, its stability, together with the ease of preparation, make this material suitable as a gas sensor. The sensing layer proved capable to detect 20 ppm of NO₂ at a temperature suitable for monitoring of exhaust gases of engines. Its high sensitivity suggests use of this sensor for environmental purposes.     

Ammonia room-temperature gas sensor using different TiO2 nanostructures

Journal of Materials Science: Materials in Electronics - In this study, three different TiO2 nanostructures, including nanowires, nanoparticles, and thin films, were synthesized by three different...     

Characterization of nanosized TiO2 based H2S gas sensor

The present investigation deals with the fabrication of H₂S gas sensor based on semiconducting oxide,TiO₂. Among the various metal oxide additives tested, Al₂O₃ is outstanding in promoting the sensing properties of nanosized TiO₂ based H₂S gas sensor. XRD pattern of TiO₂ /Al₂O₃ shows complete phase formation with anatase structure and grain growth 45 nm. The TiO₂ sensor loaded with 5 wt% Al₂O₃ and 0.5 wt% Pd shows increase in sensitivity to H₂S. The cross sensitivity of 0.5 wt% Pd:5 wt% Al₂O₃ doped TiO₂ also checked for CO, LPG and H₂ gases. The highest sensitivity for low concentration of H₂S was observed using TiO₂ based mixed Al₂O₃ and Pd. The H₂S sensor shows high sensitivity and undesirable cross sensitivity effect using TiO₂/Al₂O₃/Pd as sensing materials.     

S／TiO2纳米氧敏材料的结构与吸脱附特性

以TiCl3为钛源,采用溶胶一凝胶法,在500℃(1h)烧结获得非金属离子(硫)掺杂TiO2的纳米粉体,利用XRD,FT-IR,UV-vis,ESEM,Zeta电位,XRF,TPD等表征S/TiO2结构特性.结果表明,硫掺杂有利于其向金红石相转变,低掺杂浓度(2at%)时,硫主要以S4 形式存在,当掺杂量为25at%时,部分掺杂硫以S2-形式替代O2-,由于两者间的电负性差异,导致表面上Ti3 、Ti4 周围的电子云密度增加,从而提高样品对氧气的吸附活性,使其表面的富余电子向吸附氧转移,提高了氧敏特性.S/TiO2敏感体表面的吸附氧以氧分子形式脱附(≤550℃),而在高温(≥600℃)下主要以SO2形式脱附.     

Hydrothermal synthesis of different TiO2 nanostructures: structure, growth and gas sensor properties

A type of titanium precursor, H-exchanged titanate nanobelts, was used to prepare nanosized anatase titanium dioxide (TiO₂) with various morphologies by hydrothermal method. Nanorods, nanobelts, nano-polyhedrons and nanoparticles were successfully synthesized. We found that CTAB and EDTA-4Na⁺ play critical roles in synthesizing the nanorods and nano-polyhedrons. All the samples exhibit rapid response and recovery time to ethanol, but Nanorods, nanobelts and nano-polyhedrons show lager response than nanoparticles.     

纳米固体超强酸 SO42- /TiO2的氧敏特性研究

采用溶胶-凝胶法制备了TiO2,再用浸渍法制备纳米固体超强酸SO42-/TiO2,用XRD、TEM、IR、XPS和比表面测量等方法进行表征。结果表明纳米固体超强酸SO42-/TiO2的粒径(≤30nm)比TiO2小,并且具有很大的比表面积,Ti4+离子与SO42-的结合形式为无机双齿螯合型结构,酸强度用乙酸乙脂合成模型实验测定,确定纳米SO42-/TiO2为超强酸(SO42-/TiO2脂产率≥H2SO4脂产率)。利用固体超强酸SO42-/TiO2和纯TiO2纳米粉体分别制作成厚膜型气敏元件,固体超强酸SO42-/TiO2氧敏元件的灵敏度和工作温度等技术指标均优于纯TiO2,还进一步讨论了其氧敏特性和结构之间的关系。     

SnO2:Ga thin films as oxygen gas sensor

Ga-doped SnO₂ thin films deposited by spray pyrolysis were investigated as oxygen gas sensors. Gallium was added to the films to enhance the catalytic activity of the surface’s film to oxygen. Film resistance was studied in an environment of dry air loaded with oxygen in excess at partial pressures in the range from 0 to 8.78×10³ Pa. The best sensitivity lies close to partial pressures of 133.3 Pa. Film sensitivity reach a maximum at 350 °C. For this temperature and a doping concentration of 3 at.% of Ga in the starting solution, a sensitivity up to 2.1 was obtained.     

Development of a detection sensor for lethal H2S gas

The gas which may be lethal to human body with short-term exposure in common industrial fields or workplaces in LAB may paralyze the olfactory sense and impose severe damages to central nervous system and lung. This study is concerned with the gas sensor which allows individuals to avoid the toxic gas that may be generated in the space with residues of organic wastes under 50 degrees C or above. This study investigates response and selectivity of the sensor to hydrogen sulfide gas with operating temperatures and catalysts. The thick-film semiconductor sensor for hydrogen sulfide gas detection was fabricated WO3/SnO2 prepared by sol-gel and precipitation methods. The nanosized SnO2 powder mixed with the various metal oxides (WO3, TiO2, and ZnO) and doped with transition metals (Au, Ru, Pd Ag and In). Particle sizes, specific surface areas and phases of sensor materials were investigated by SEM, BET and XRD analyses. The metal-WO3/SnO2 thick films were prepared by screen-printing method. The measured response to hydrogen sulfide gas is defined as the ratio (Ra/R,) of the resistance of WO3ISnO2 film in air to the resistance of WO3/SnO2 film in a hydrogen sulfide gas. It was shown that the highest response and selectivity of the sensor for hydrogen sulfide by doping with 1 wt% Ru and 10 wt% WO3 to SnO2 at the optimum operating temperature of 200 degrees C.     

TiO2膜光催化水处理设备的研制和应用

以大流量处理微污染水为目的,采用溶胶-凝胶法在炻器管内壁负载纳米TiO2膜,以150 W低压汞灯为主要光源置于管内组成光催化反应膜管,由多根膜管组成的光催化水处理设备的总膜面积为6.13 m2,总反应容积为105.38 L,低压汞灯总功率为2 100 W.当处理量为0.5 t/h时,某印染废水、制药废水和南京秦淮河水的CODCr值分别由初始的104 mg/L,63mg/L,24 mg/L降低为37 mg/L,19 mg/L,12 mg/L,去除率分别为64.4%,70%,50%.降低处理量可提高CODCr去除率,但能耗增加.南京秦淮河水样含细菌总数4.1×106个/L,大肠菌群数1.7×104个/L,经光催化设备处理后,灭菌率为100%,日光照射10 h无细菌复活.采用1 mol/L的H2SO4溶液浸泡24 h,污染的TiO2膜光催化降解能力可以恢复到初始的95%.