NA.3 - Importance of Hierarchical Nano-Morphology for High Performance Potentiometric Sensors
- 17th International Meeting on Chemical Sensors - IMCS 2018
2018-07-15 - 2018-07-19
- Nanoarchitectures in Sensing
- J. Yi, H. Zhang, Z. Zhang - State Key Laboratory of Fire Science, Department of Safety Science and Engineering, University of Science and Technology of China, Hefei, Anhui (China)
- 284 - 285
Hierarchical nanostructured materials have been widely studied in many fields like semiconducting gas sensors due to the peculiar properties arising from the large surface/volume ratio. Nevertheless, similar studies have been rarely conducted for mixed-potential gas sensors. The response of such sensors is governed jointly by the rate of electrochemical reactions at the three phase boundary and of the heterogeneous reaction at the electrode surface, and thus closely related with the morphology and microstructure of the electrodes. In this work, a planar mixed-potential sensor was prepared based on SnO2 sensing electrode of hierarchical porous hollow nanofibers. As compared with a similar sensor with sensing electrode of SnO2 nanoparticles, the nanofiber sensor exhibited much superior H2 sensing performance, achieving 5 times larger response values and 2.6 times shorter response time at 450 ºC for 1000 ppm H2. Moreover, excellent selectivity, long-term stability, and repeatability were also achieved. The morphology-dependent sensing behavior will be discussed in terms of the diffusion-reaction process. These results highlight the importance of morphology to mixed-potential gas sensors, and show that hierarchical nanofiber electrode is desirable for achieving high gas sensing performance.