کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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742359 | 1462113 | 2013 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Gas sensing properties of Gd2O3 microspheres prepared in aqueous media containing pectin Gas sensing properties of Gd2O3 microspheres prepared in aqueous media containing pectin](/preview/png/742359.png)
Single phase Gd2O3 hollow microspheres were prepared by a direct aqueous solution–coprecipitation method. The synthesis was performed in presence of formic acid and pectin. The precursor dried at 170 °C was identified as gadolinium formate. The calcination at 500 °C produced single-phase Gd2O3. Hollow microspheres, with diameter between 0.7 μm and 2.5 μm were observed by SEM. Their inspection by TEM revealed that the shells of the microspheres were formed by a network of interconnected nanoparticles. Nanoporosity was also observed in these shells. The use of formic acid played a key role in the formation of Gd2O3 microspheres. The synthesis using acetic acid and pectin produced a material with an irregular shape. The CO2 and CO gas sensing characterization was performed on thick films using AC (impedance). The films were prepared by a simple deposition method, using the as-prepared microspheres. The n-type semiconductor behavior of Gd2O3 was confirmed by its response to the test gases. Repeatability and reproducibility in the detection of the gases was observed at 470 °C. A significant better performance was observed in CO2. Polarization curves qualitatively agreed with the impedance measurements.
Journal: Sensors and Actuators B: Chemical - Volume 177, February 2013, Pages 390–396