【作者】 赵佳一；

【导师】 谢全安； 王岭；

【作者基本信息】 河北理工大学 ， 化学工艺， 2010， 硕士

【摘要】 采用高温固相反应法,制备不同煅烧温度的质子导体BaCe0.7Nb0.1Y0.2O3-δ,掺杂不同浓度的质子导体BaCe0.8-xNbxGd0.2O3-δ(0≤x≤0.45)和掺杂不同元素的质子导体BaCe0.7M0.1Y0.2O3-δ(M=Zr, Ti, Zn, Sn, Nb)。采用XRD、SEM及EIS等技术分别研究所制备材料的物相结构、微观形貌和电导率。研究了其在含有水蒸气、H2和CO2气氛中的稳定性。分别以BaCe0.7Zn0.1Y0.2O3-δ:Ce0.8Y0.2O2=5:5(体积比,传感器1)和6:4(传感器2)的混合导体为致密扩散层,以质子导体BaCe0.7Zn0.1Y0.2O3-δ为固体电解质,制备了极限电流型氢气传感器,对氢气传感器的氢敏性能进行了研究。研究结果表明:所制备的质子导体均为钙钛矿结构。BaCe0.7Nb0.1Y0.2O3-δ烧结样品的致密性随着煅烧温度的升高而增加,与热力学计算结果一致;700℃时样品在含有水蒸气和氢气的气氛中稳定性良好,但在纯CO2气氛中不够稳定;在湿润4000ppmH2/Ar气氛下,粉体煅烧温度不同的样品电导率相差不大;质子导体BaCe0.7Nb0.1Y0.2O3-δ的最佳煅烧温度为1300℃。BaCe0.8-xNbxGd0.2O3-δ(0≤x≤0.45)烧结样品的致密性随着x值的增大而增加;700℃时该系列质子导体对水的稳定性良好,对纯CO2的稳定性随着x值的增大而提高,而该系列质子导体在800℃时对纯CO2的稳定性优于700℃,与热力学计算结果一致;在湿润4000ppmH2/Ar气氛下,其电导率随着x值的增大而减小;x=0.1的烧结样品性能最好。BaCe0.7M0.1Y0.2O3-δ(M=Zr, Ti, Zn, Sn, Nb)烧结样品的致密性由好到差依次为Zn、Nb、Ti、Sn、Zr。700℃时所有烧结样品在含有水蒸气和氢气的气氛中表现出良好的稳定性,但在纯CO2气氛中不够稳定;在湿润4000ppmH2/Ar气氛下,Ti掺杂的烧结样品电导率最小,Zr掺杂的烧结样品电导率最大。传感器1和传感器2在工作温度为700℃、氢浓度为50~999ppm范围内、电压为0.4V时,响应电流与氢浓度存在良好的线性关系,相关系数分别为0.998和0.995;灵敏度分别为3.137和2.349μA·ppm-1。更多还原

【Abstract】 Proton conductors BaCe0.7Nb0.1Y0.2O3-δin different calcination temperature, proton conductor BaCe0.8-xNbxGd0.2O3-δ(0≤x≤0.45) doped with different concentrations and proton conductor BaCe0.7M0.1Y0.2O3-δ(M=Zr, Ti, Zn, Sn, Nb) doped with different elements were prepared by high-temperature solid-state reaction method. Through using the technology of XRD, SEM and EIS, phase structure, micro-morphology and electrical conductivity of the materials were studied respectively. The stability in the atmosphere containing water vapor, H2 and CO2 was also studied. The limiting current hydrogen sensors were prepared with the dense diffusion layer of mixed conductors BaCe0.7Zn0.1Y0.2O3-δ: Ce0.8Y0.2O2=5:5(volume ratio, sensor 1) and 6:4(sensor 2) and with the solid electrolyte of BaCe0.7Zn0.1Y0.2O3-δ, then the hydrogen-sensitive properties of it were studied.The results showed that all of proton conductors formed perovskite structure. The densification of sintered samples of BaCe0.7Nb0.1Y0.2O3-δincreased with the calcination temperature of powders raised. This conclusion was also consistent with thermodynamic calculations. At 700℃, the stability of all the sintered samples was good in the atmosphere containing water vapor and H2, but it was poor in the atmosphere of pure CO2. In wet 4000ppmH2/Ar atmosphere, the conductivity of sintered samples of different calcination temperature was or less. The optimal calcination temperature of proton conductor BaCe0.7Nb0.1Y0.2O3-δwas at 1300℃.The densification of sintered samples of BaCe0.8-xNbxGd0.2O3-δ(0≤x≤0.45) increased with the value of x increased. At 700℃, the stability of all proton conductors was good in the atmosphere containing water vapor, and the stability increased with the value of x increased in pure CO2. But the stability of all proton conductors at 800℃was better than at 700℃in the atmosphere of pure CO2. This conclusion was also consistent with thermodynamic calculations. In wet 4000ppmH2/Ar atmosphere, the conductivity decreased with the value of x increased. When x = 0.1, the property of the sintered samples was best.The densification of sintered samples BaCe0.7M0.1Y0.2O3-δ(M=Zr, Ti, Zn, Sn, Nb) from good to poor was followed by Zn, Nb, Ti, Sn, Zr. At 700℃, the stability of all the sintered samples was poor in the atmosphere of pure CO2, but it was good in the atmosphere containing water vapor and H2. In wet 4000ppmH2/Ar atmosphere, the conductivity of sintered samples of Ti-doped and Zr-doped was the minimum and maximum respectively.At 700℃, there was a good linear relationship between response current at 0.4V and hydrogen concentration, hydrogen concentration was in the range of 50~999ppm, of sensor 1 and sensor 2. The correlation coefficient was 0.998 and 0.995, and the sensitivity was 3.137 and 2.349μA ? ppm-1 at 700℃, respectively.更多还原