掺Rh对纳米SnO_2的气敏性能的影响

Influence of Doping Rh on the Gas Sensitive Properties of Nanometer—sized SnO_2

以无机试剂为前驱物,采用溶胶—凝胶法合成了纳米级 SnO_2,以此为基材掺入不同量 Rh 作为气敏材料制成气敏元件。测试了它们的阻温特性和气敏性能。通过比较它们对还原性气体的灵敏度和选择性,讨论了掺入 Rh 催化剂对纳米 SnO_2的阻温特性和气敏性能的影响。结果表明,纳米 SnO_2具有特征的阻温曲线。随着 Rh 催化剂掺入,不仅引起电阻增大,同时掺杂 Rh 占据表面活性位,使纳米 SnO_2对表面氧吸附时的物种类型相互转换的影响体现不出来。不过,在工作温度为300℃时。掺入0.2%Rh 催化剂使得纳米级 SnO_2对 C_2H_5OH 和 petrol、H_2的灵敏度提高了10倍以上,而且使其对 petrol 与 C_4H_(10)的选择性检测性提高了3倍以上,对 C_2H_5OH 与 CO 的选择性检测性提高2倍以上。

A gas sensitive material,nanometer—sized SnO_2 particle,was prepared by a Sol- gel method using inorganic salt as a precursor material.Its resistivity change and the gas sensitivity varied with temperature were measured in various reducing gases.The influence of Rh on gas sensitive properties of nanometer—sized SnO_2 was studied.The results indi- cated that there is a peculiar resistance change varied with temperature for nano—SnO_2.It was relevance to the increase in surface adsorbed oxygen.When rhodium ion was doped in nano—SnO_2 as a catalyst,the selective detections to C_4H_(10) and petrol can be increase up 3 times higher and the gas sensitivities are increased largely to C_2H_5OH,petrol and H_2.