Pechini法制备(La_(0.8)Sr_(0.2))_2FeNiO_(6-δ)材料以及烧结温度对其NO_2敏感性的影响

Preparation of (La_(0.8)Sr_(0.2))_2FeNiO_(6-δ) Materials by Pechini Method and Effect of Sintering Temperature on Its NO_2 Sensitivity

为开发高性能车载NO_2气体传感器敏感电极材料,以La_2O_3和Sr、Fe、Ni的硝酸盐、柠檬酸和乙二醇为原料,在pH=8～9的碱性条件采用Pechini法合成了约80～90 nm的复合氧化物(La_(0.8)Sr_(0.2))_2FeNiO_(6-δ)(LSFN)双钙钛矿粉末材料,并对合成工艺中柠檬酸(CA)与金属阳离子(M)的配比进行了研究。采用丝网印刷将其制备成基于氧化钇稳定氧化锆(YSZ)的NO_2传感器的敏感电极。运用TG/DTA、XRD、FSEM和ESEM对粉末材料和敏感电极进行了表征,并研究了烧结温度对LSFN敏感电极的NO_2敏感性的影响。研究结果表明:适当的柠檬酸与金属阳离子(CA/M)配比可降低材料的成相温度。XRD测试结果表明,LSFN的结构对称性会被烧结温度改变。对不同温度下烧结的LSFN敏感电极在550℃下的NO_2敏感性测试结果表明,其敏感性受烧结温度的影响,不同烧结温度下敏感电极形态可调控其NO_2敏感性。1300℃烧结的LSFN敏感电极的传感器具有较好的三维网络结构和最薄的电极厚度,表现出最高的NO_2敏感性,其灵敏度高达130. 17 m V/decade。

In order to develop sensitive electrode(SE)materials for high-performance on-vehicle NO 2 gas sensors,La 2O 3 and Sr,Fe,Ni nitrates,citric acid,and ethylene glycol were used as raw materials.A composite oxide(La 0.8 Sr 0.2)2FeNiO 6-δ(LSFN)double perovskite powder with a particle size of about 80-90 nm was synthesized by the Pechini method at alkaline conditions with pH=8 to 9.The ratio of citric acid(CA)and metal cation(M)in the synthesis process was studied.LSFN was prepared by screen printing as a SE of an yttria-stabilized zirconia(YSZ)-based NO 2 sensor.The TG/DTA,XRD,FSEM and ESEM were used to characterize the powder material and the SE.The effect of sintering temperature on the sensitivity of NO 2 to the LSFN-SE was studied.The results show that the appropriate acid and metal cation ratio(CA/M)can reduce the phase formation temperature of the material.XRD test results show that the structural symmetry of LSFN can be changed by the sintering temperature.The sensitivity test of NO 2 at 550℃for LSFN-SEs sintered at different temperatures shows that the sensitivity of the sensor is affected by the sintering temperature.The morphology of the LSFN-SE can modulate the NO 2 sensitivity at different sintering temperatures.The sensor of LSFN-SE sintered at 1300℃has a good three-dimensional network structure and the thinnest electrode thickness,exhibiting the highest sensitivity of NO 2,and its sensitivity is as high as 130.17 mV/decade.