Titanium dioxide film hydrogen sensor and preparation method thereof

Abstract

The invention provides a titanium dioxide film hydrogen sensor and a preparation method thereof. The predeposited TiO2 seed crystal layer can isolate the FTO (fluorine-doped tin oxide) conducting layer and hydrothermal growth TiO2 layer, lower the drain current passing through the FTO conducting glass layer and enhance the detection sensitivity of the titanium dioxide film hydrogen sensor; the predeposited TiO2 seed crystal layer can be used as a buffer layer and seed crystal layer, provides a higher-density seed crystal layer for the next hydrothermal synthesis step of the TiO2 nano array film, and effectively increases the density of the film TiO2 nanorod array; and magnetron sputtering and hydrothermal synthesis are combined to enhance the grain orientation performance of the TiO2 nano array film, so that the finally prepared titanium dioxide film hydrogen sensor has excellent detection sensitivity and stability, and more importantly, can satisfy the requirements for hydrogen detection at 25+ / -5 DEG C, and the method does not need any additional heating system and has the advantage of lower cost than other methods. The detection limit at 25+ / -5 DEG C can reach 1 ppm, and the resistance change is up to 4% when a 1V voltage source is used as the drive.

Description

technical field [0001] The invention relates to a hydrogen sensor, in particular to a titanium dioxide thin film hydrogen sensor and a preparation method thereof. Background technique [0002] As an emerging important renewable energy carrier and the most important industrial gas and special gas, hydrogen has been widely used in petrochemical industry, electronics industry, metallurgical industry, food processing, float glass, fine organic synthesis, aerospace, etc., but when When the hydrogen content in the air reaches 4%, it is very easy to explode, which brings great safety hazards to the application and storage of hydrogen. Therefore, a sensor that can sensitively detect hydrogen, has stable performance and is cheap has become a must in today's industrial field. Urgent needs. [0003] At present, a variety of gas sensors have appeared on the market, mainly electrochemical, semiconductor, pyroelectric, metal and optical, among which TiO 2 Because of its stable surface p...

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Problems solved by technology

[0004] Existing oxide gas sensors have the following problems: First, the operating temperature is high, and the best working condition is generally reached at 200-300°C. Studies have shown that high temperature will reduce the activation of hydrogen adsorption and analysis on the sensor surface It is beneficial to the improvement of detection sensitivity, but it also brings great safety hazards and increases energy consumption; second, the low detection limit of hydrogen needs to be improved. It has been recorded in relevant literature that a rutile phase TiO 2 The minimum detection limit of the film for hydrogen can reach 5ppm when the working temperature is 500°C (Lu, C.; Chen, Z. High-temperature resistive hydrogen sensor based on thin nanoporous rutile TiO 2 film on anodic aluminum oxide. Sens. Actuat. B 2009, 140, 109–115.), the detection limit of Mg-doped ZnO to hydrogen can reach 5ppm, and the working temperature to reach this detection limit is reduced to 150°C (Liu, Y. ; Hang, T.; Xie, Y.; Bao, Z.; Song, J.; Zhang, H.; Xie, E. Effect of Mg doping on the hydrogen-sensing characteristics of ZnO thin films. Sens. Actuat. B 2011, 160, 266–270.); Third, under working conditions, the resistance of the hydrogen sensor changes little

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