铜掺子铜掺杂纳米TiO_2氢气敏感性研究

Hydrogen Sensitvity of Nano-TiO_2 by Doping Copper

采用溶胶-凝胶法制备锐钛矿型纳米TiO2粉体，平均颗粒直径50nm左右．在粉体中加入1-5at%Cu作为催化剂，其以CuO形式存在．在氢分压1000×10^-6／Ar，不同温度下（100-500℃）测定材料的电阻率变化，发现与纯纳米TiO2相比，掺Cu的纳米TiO2在整个温度区间均可提高材料的氢气敏感性，提高幅度在50％左右，研究了工作温度与响应时间的变化关系，发现掺Cu纳米TiO2在400℃表现有最好的气敏性，和最快的响应时间．对这种材料氧气气敏性及添加CuO的作用机理进行了分析．认为在纳米TiO2中加铜后，主要是CuO与吸附氢气的化学反应作用，后者是提高纳米TiO2材料气敏性和减少响应时间的主要原因．

The nanoparticle TiO2 powder with anatase structure was prepared by sol-gel method, and it was doped with 1-Sat% copper as a catalyst for hydrogen adsorption, and the doping copper exists as CuO form. The average particle size was about 50 nm. In the hydrogen partial pressure 1 000×10^-6/H2/Ar, the resistance of the nano-TiO2 doped or undoped copper were measured in the temperature range 100-500℃ with or without hydrogen respectively. The results showed that the resistance of the nano-TiO2 by doping copper was more sensistive for hydrogen than that of pure TiO2 in the temperature range of 100-500℃. The sensitivity of the nano-TiO2 by doping copper for hydrogen was increased about 50 %. The relationship between the sensitivity and the operating temperature and response time of the gas-sensor material for hydrogen was also researched. The results showed that there was a maximum sensitivity and the fastest response time for hydrogen at about 400℃. The catalyst mechanism of the nano-TiO2 by doping copper for hydrogen was discussed. The reduce reaction between CuO and the adsorption hydrogen was regarded as the main reason to increase the hydrogen senstivity of the nano-TiO2.