Cu掺杂SnO2纳米粉体的制备及气敏特性

控制不同n(Cu2+)/n(Sn4+),用均匀共沉淀法制备了平均粒径约80 nm的金红石型结构Cu掺杂SnO2纳米粉体;并以白云母为基片制备出Cu掺杂SnO2气敏元件。用TG-DSC、XRD、SEM对样品的相变、结构、形貌进行了分析,并测试了气敏元件的阻温特性和75℃氢气敏感性能。结果表明,Cu掺杂抑制了SnO2晶核的生长,使SnO2结晶度由约75%减小到50%,晶粒尺寸由约18 nm减小到6 nm;Cu掺杂使n型半导体SnO2的空气电阻值由1~8 kΩ提高到9×105~3×107MΩ,并使元件在75℃对体积分数为2 000×10-6氢气的灵敏度提高约20倍;n(Cu2+)/n(Sn4+)≈0.01时,元件对体积分数为4 000×10-6氢气的灵敏度高达约42。

Preparation and Gas Sensing Characteristic of Cu-Doped SnO2 Nano-powders

Cu-doped SnO2 nano-powders were prepared by homogenous co-precipitation method with different n(Cu2+)/n(Sn4+).The rutile type Cu-doped SnO2 grains were about 80 nm.The phase transformation,structure and shape of samples were analyzed according to TG-DSC,XRD and SEM.The resistance-temperature characters and sensitivities in H2 atmosphere at 75 ℃ of the sensors were tested.As a result,doping of Cu2+ restrains the growth of grains.The crystalline degree of SnO2 decreases from about 75% to 50% and the crystal size of SnO2 decreases form about 18 nm to 6 nm.In addition,doping of Cu2+ increases the resistance of n-type SnO2 from 1～8 kΩ to 9×105～3×107 MΩ in the air atmosphere and improves the sensitivities of sensors by about 20 times for 2 000×10-6 H2 at 75 ℃.The sensitivity of sensors for 4 000×10-6 H2 was as good as 42 when n(Cu2+)/n(Sn4+) was about 0.01.