Preparation method of gas-sensitive test element based on lanthanum molybdate nano material

Abstract

The invention discloses a preparation method of a gas-sensitive test element based on a lanthanum molybdate nano material. The preparation method uses lanthanum nitrate and ammonium molybdate as raw materials, and comprises the steps of: weighing a certain amount of La(NO3)3 and (NH4)6Mo7O24 according to the stoichiometry of LMO, using distilled water as a solvent, adding citric acid, wherein the molar ratio of citric acid and metal cation is 2:1-1:1; and using a microwave assisted method to prepare the lanthanum molybdate nano material; and preparing the gas-sensitive test element based on the nano material. The method optimizes the synthetic process of LMO to endow the LMO material with nano scale, and the material has the advantages of uniform morphology, good repeatability and high chemical activity, has excellent gas-sensitive response characteristics in the middle temperature section, reaches the sensitivity of 31 to 200ppm ethanol gas at 260 DEG C and has good response recovery ability.

Description

technical field [0001] The invention belongs to the technical field of electronic functional materials, and in particular relates to a preparation method of a gas-sensing test element based on lanthanum molybdate nanometer material. Background technique [0002] Lacorre et al. reported a new type of oxygen ion conductor material, lanthanum molybdate La 2 Mo 2 o 9 (LMO), its oxygen ion conductivity at 800 °C reached 0.06S cm -1 Above, "P. Lacorre, F. Goutenoire, O. Bohnke, R. Retoux, NATURE, 2000, 404, 856". by O 18 The oxygen ion diffusion coefficients of pure and doped LMO samples at 800°C were measured by isotope to be (0.5~3)×10 -6 cm 2 the s -1 , high oxygen ion conductivity and high oxygen ion diffusion coefficient are corresponding, which are higher than traditional yttria-stabilized zirconia (YSZ) and doped lanthanum gallate materials. Due to the simple preparation process and cheap raw materials, lanthanum molybdate has a great competitive advantage as a cand...

AI Technical Summary

Problems solved by technology

However, the application of lanthanum molybdate as a gas sensor has not been reported yet.

[0003] Various methods such as solid phase sintering method, sol-gel method, freeze-drying method, polymer precursor method, hydrothermal method, and in-situ polymerization method have been used at home and abroad to prepare lanthanum molybdate materials with different shapes and sizes. It has made some scientific research progress, but there are disadvantages such as uneven morphology, poor stability, complex synthesis process, long cycle time, and high cost.

For gas sensing materials, semiconductor gas sensing materials have shortcomings such as short service life, poor stability, and strict preparation, while traditional ion conductor-based YSZ materials require higher operating temperatures and have lower activity.

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