Dissertation > Excellent graduate degree dissertation topics show

Preparation, Doping and Gas-Sensing Properties of Indium Oxides

Author: LiPei
Tutor: LouXiangDong
School: Henan Normal
Course: Inorganic Chemistry
Keywords: In2O3 Surfactant Hydrothermal Doping
CLC: O614.372
Type: Master's thesis
Year: 2010
Downloads: 63
Quote: 1
Read: Download Dissertation

Abstract


Indium oxide （In2O3） is an n-type semiconductor that shows t a wide band-gap and a low resistance and good catalysis. In2O3 nanometer materials, is an interesting material with excellent properties in applications such as solar cells, liquid crystal displays, gas sensor, Nowadays, zinc based composite oxides materials have become a hot topic in research and development. Composite oxide gas sensor can be applied to many aspects, such as agriculture, biological process, construction, and so on.In2O3 nano-powder was prepared by several methods. Its size, phase and morphology were analyzed by XRD, SEM and TEM. The results show that the morphology of the In2O3 prepared by the room temperature solid-phase synthesis, hydrothermal method and chemical co-precipitation method were nanorods. The gas-sensing properties of the materials were tested in static state. The results show that theIn2O3 nano-powder has high sensitivity to Cl2. The In2O3 nano-powder prepared by homogeneous-precipitation method has a highest sensitivity as high as 1175 to 100ppm Cl2 at lower working temperature 110℃. The sensor based on In2O3 also has satisfactory selectivity, quickly response and short recover time.In2O3 nano–powder was prepared by hydrothermal methods with Polyethylene glycol （PEG） 400/600/1000/2000 and series of EO （Textlo）. The results show In2O3 nanorods can successfully prepared by a one–step hydrothermal method with PEG–600. In2O3 nanobelts were successfully synthesized by a one-step hydrothermal method. The average length of the nanorods reaches 150 nm, and the width 20 nm, giving an aspect ratio of a few hundreds. The In2O3 sensor has a high sensitivity up to 32.2 to 10 ppm NO2 at lower working temperature 175℃. The sensor based on In2O3 also has satisfactory selectivity, quickly response and recover times. Using Textlo138 as surfactant, In2O3 nanobelts were synthesized by a one–step hydrothermal method. The average length of the nanobelts reaches 200 nm, and the width 10 nm. The results demonstrated that the In2O3 sensor has a high sensitivity up to 10.6 to 10 ppm Cl2 at the working temperature 290℃. The response time to 10 ppm Cl2 was about 8s, and the recovery time was about 1s. In order to improve the sensitivity of In2O3, doping is an effective way. In this work, metal elements were doped to In2O3in our work, such as Fe, Co, Ni. The result show that doped with metal elements, the sensitivity to NO2 and Cl2 increased significantly. The sensor In2O3 doped with 7 wt% Fe（NO3）3 has the best gas-sensing capability. So was the sensor In2O3 doped with 5wt% Co（NO3）2 and 7wt% Ni（NO3）3. Take Ni（NO3）3 as an example, the sensor In2O3 doped with 7wt% Ni（NO3）3 has the best gas-sensing capability, its sensitivity to 100ppm Cl2 can reach 843.1 at the working temperature 350℃.When the Cl2 concentration is 10ppm, the gas response is 28.5, so the sensors can test Cl2 concentration of even lower than 10ppm. The sensor based on In2O3 also has satisfactory selectivity, quickly response and short recover time.Rare earth elements were also doped to In2O3, such as La, Ce, Pr, Nd. The result show that doped with rare earth elements, the sensitivity to NO2 and Cl2 increased significantly. The sensor In2O3 doped with 7wt% rare earth elements La（NO3）3 has the best gas-sensing capability. The sensor In2O3 doped with 3wt% Ce（NO3）3, 7wt% Pr6O11, 7wt% Nd（NO3）3 has the best gas-sensing capability, too. Take La as an example, the sensor In2O3 doped with 7wt% La（NO3）3 has the best gas-sensing capability, its sensitivity to 100ppm Cl2 can reach 1665.667 at lower working temperture110℃, and also has satisfactory selectivity; quickly response and short recover time.

Related Dissertations

  1. Preparation and Photocatalytic Properties for Water Decomposition of Titanate Photocatalyst,O643.36
  2. Hydrothermal Synthesis of Oxide Hollow Spheres,TB383.4
  3. Application of Additives’ Drag Reducing Technology in District Heating System,TU995
  4. Study of Tin Alloy Carbon Composite Used for Lithium Ion Battery,TM912.9
  5. The Study of Preparation and Photocatalytic Activity of TiO2 by Electrospinning,O614.411
  6. Study and Preparation of BaTiO3-based NTC Ceramic Thermistors,TQ174.1
  7. First- principles calculations of doped anatase titanium dioxide photocatalytic properties,O643.36
  8. Flexible,rigid,Synthesis and characterization of mixed ligand complexes,O621.1
  9. Synthesis and Characterization of Carbonate Intercalated Layered Double Hydroxides and Their Structure Recovery Properties,TQ424.2
  10. Effectiveness Comparison of Different Solvents in Organochlorine Pesticide (OCP)-Contaminated Soil Flushing and Optimization of Flushing Parameters,X592
  11. Studies on the Isolation of Oil-Degrading Bacteria with Biosurfactant Production and Their Characteristics,X172
  12. Preparation of Layered Double Hydroxide Material and Research Adsorption Capacity,O611.4
  13. Preparation of One-dimensional Nano TiO2 and Study on the Decolorization of Dyeing Wastewater,TB383.1
  14. Adsortions of Dye by Modified Activated Carbon and Heavy Metals by Rice Husk-Based Activated Carbon,X703
  15. First-Principles Studies of Cathode Material LiMO2 （M=Co, Ni, Mn） of Lithium Ion Batteries,TM912
  16. Iron, lanthanum -doped nano TiO \u003csub\u003e 2 \u003c/ sub\u003e Preparation and photocatalytic properties,O614.411
  17. Determination of Organophosphorus Pesticides Residues by Fluorescence Method and Its Application,O657.39
  18. Experimental Study of Wettability of Coal and New Wetting Agent,TD714
  19. Research on the Modified Methods of Fly Ash for Ammonia-nitrogen Wastewater Treatment,X703
  20. Copper oxide porous hollow microspheres Preparation and Characterization,O614.121
  21. High hydrothermal stability of nickel-based catalyst and hydrogenation of butyne diol,TQ223.162

CLC: > Mathematical sciences and chemical > Chemistry > Inorganic Chemistry > Metal elements and their compounds > Section III group metal elements and their compounds > The gallium Vice family ( Ⅲ A group metal elements ) > Indium In
© 2012 www.DissertationTopic.Net  Mobile