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Enhanced ammonia sensing characteristics of CeO2-decorated SiO2/PANI free-standing nanofibrous membranes

Pang, Zengyuan, Nie, Qingxin, Zhu, Yanan, Ge, Mingqiao, Chen, Mingqing
Journal of materials science 2019 v.54 no.3 pp. 2333-2342
ammonia, ceric oxide, electrospraying, nanofibers, polymerization, silica
CeO₂-decorated SiO₂/PANI free-standing nanofibrous membranes were fabricated using an approach which involved electrospinning–electrospraying, calcination and in situ polymerization. Specifically, the CeO₂ precursor deposition on the electrospun nanofibers surface was done through electrospraying, followed by the calcination which resulted in CeO₂ particles and SiO₂ free-standing nanofibers. By incorporating CeO₂, ammonia sensing properties of the as-prepared SiO₂/PANI free-standing composite nanofibers (SiO₂/PANI FCN) can be dramatically improved. The sensing response value of SiO₂/CeO₂/PANI free-standing composite nanofibers (SiO₂/CeO₂/PANI FCN), analyzed with 300 ppm ammonia, was ca. 36.98, which was superior to SiO₂/PANI composite nanofibers. The ammonia sensing mechanism of the SiO₂/CeO₂/PANI FCN can be attributed to the P–N heterojunctions formed between p-type PANI and n-type CeO₂. Furthermore, the SiO₂/CeO₂/PANI free-standing ammonia sensor presented ideal selectivity and repeatability. This work provided a new insight into the development of free-standing and high-performance gas sensors.