Tungstic oxide nano-wire and method for preparing tungstic oxide nano-wire gas-sensitive sensor

Abstract

The invention relates to a method for preparing a tungsten oxide nano-wire and a tungsten oxide nano-wire ammonia-sensitive sensor, belonging to the one dimensional nano oxide material preparation and gas-sensitive technical field. The method comprises the following steps that: sodium tungstate is dissolved in deionized water to prepare a sodium tungstate solution; a hydrochloric acid is dripped slowly to prepare a flaxen micellar solution which is then centrifugally separated; products are uniformly dispersed in a potassium sulfate solution which is then transferred into a reaction kettle for hydrothermal reaction, and then the tungsten oxide nano-wire is prepared; adhesives and frit are added into the tungsten oxide nano-wire, and then the tungsten oxide nano-wire ammonia-sensitive sensor is prepared after element sintering and ageing. The method has simple steps, easily controlled technological parameters during the preparation process, and very low energy consumption during the whole preparation process; the tungsten oxide nano-wire prepared has a large specific surface area and high thermal stability; and the tungsten oxide nano-wire ammonia-sensitive sensor prepared has high sensitivity on low-concentration (between 1 and 100 pars per million) H2, CO and NH3, good repeatability and high stability.

Description

technical field [0001] The invention relates to a wide-range hydrothermal preparation method of hexagonal tungsten oxide (WO3) nanowires and gas-sensing applications, and belongs to the technical field of preparation of one-dimensional nano-oxide materials and gas-sensing. Background technique [0002] Among many metal oxides, tungsten oxide is a transition metal oxide, which belongs to n-type semiconductor and has a wide range of uses. At present, a large number of studies have found that tungsten-based oxides not only serve as catalytic, electrochromic, solar absorbing materials, and stealth materials, but also have the characteristics of semiconductor functional materials such as heat-sensitive, pressure-sensitive, and gas-sensitive materials. The application and research of tungsten oxide nanocrystalline films in gas sensors, photocatalysis, photoconductivity, etc. are attracting more and more people's attention, especially in the application field of oxide semiconductor...

AI Technical Summary

Problems solved by technology

[0004] At present, the preparation technology of tungsten oxide nanowires still has many problems such as complex process, high energy consumption, and difficulty in large-scale promotion.

For example, Andrea Ponzoni et al. (Andrea Ponzoni et al. Applied Physics Letters, 88: 203101-1-203101-3, 2006) prepared WO3-X nanowire network structure by evaporating tungsten powder at 1400-1450°C. The wire network structure is composed of nanowires with a diameter of tens of nanometers to 200nm, but the temperature, pressure, evaporation time and other parameters must be strictly controlled during the preparation process, and the entire reaction is carried out in a vacuum chamber with argon at a certain flow rate. , the preparation temperature is as high as 1400-1450°C, which increases energy consumption to a great extent and makes it difficult to achieve large-scale production

At the same time, at present, most of the application research on tungsten oxide-based gas-sensing materials at home and abroad is mainly focused on the research of polycrystalline films composed of large grain sizes. Sensitivity and selectivity of sensors made of sensitive materials are not ideal, and high sensitivity and repeatability can only be obtained by increasing the test temperature or by doping other materials

There are only a few reports on the application of tungsten oxide nanowire gas-sensing materials, and most of these studies are still in the laboratory research stage, and all of them have the following shortcomings to varying degrees: the preparation process of tungsten oxide nanowires is very complicated; Raw materials are expensive; precursors need to be treated at high temperature; the later film formation cycle is long; it is very difficult to obtain a sensitive film with good sensitivity and stable gas sensitivity

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