No abstract

In this paper, pure and 1.5, 2.5 and 3.5 at.-% samarium oxide (Sm 2 O 3 ) doped tin oxide (SnO 2 ) nanorods were successfully synthesised with a facile and environment friendly hydrothermal process. All the as prepared nanostructures were carefully characterised by X-ray diffraction, field emission SEM, TEM, high resolution TEM and X-ray photoelectron spectroscopy respectively. Planar sensors were further fabricated with the as synthesised samples, and their sensing properties towards acetylene gas (C 2 H 2 ), an extremely significant fault characteristic gas dissolved in oil immersed power transformers, were systematically measured. Interestingly, the sensing properties of the fabricated SnO 2 nanorod based sensor to C 2 H 2 gas can be obviously enhanced by adding Sm 2 O 3 , and the sensor doped with 3.5 at.-%Sm 2 O 3 displays the most superior sensing characteristics, including operating temperature, sensitivity, response and recovery time, etc., as compared to other three cases. All results indicate that the synthesised Sm 2 O 3 doped SnO 2 sensing material might be a promising candidate for C 2 H 2 sensing and lay a solid foundation for exploring high performance chemical gas sensor to detect C 2 H 2 gas extracted from power transformer oil.

In this study, a facile hydrothermal method was adopted to fabricate SnO 2 and CuO-SnO 2 nanoparticles. The CuO content was chosen as 5 mol.-% (sample 1), 10 mol.-% (sample 2) and 15 mol.-% (sample 3). Microstructures and surface morphologies for all samples were characterised by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). A systematic comparison study reveals an enhanced gas sensing performance for the CuO-SnO 2 gas sensor towards CO gas. The improved gas sensing properties are attributed to the formation of p-n junctions and the absorbed oxygen species as well as to the heterojunctions of the CuO to the SnO 2 nanoparticles which provide additional reaction rooms. The results represent an advance of heterojuction nanostructures in further enhancing the functionality of gas sensors, and this simple method could be applicable to many sensing materials.

No abstract