Ting Qu,Qiang Tan,Liting Liu,Shengwu Guo,Sai Li,Yongning Liu
The wide application of direct ethanol fuel cells (DEFCs) was blocked by the sluggish catalytic activity of catalysts, insufficient ionic conductivity of the polymer electrolyte membrane (PEM), and ethanol crossover issues. To overcome the problems mentioned above, a novel DEFC system with a polymer fiber membrane (PFM) and nonplatinum catalysts is proposed. In this system, the performance of the anode catalyst Pd/C is significantly promoted by homogeneous Ni-doped SnO2 nanoparticles, and the inexpensive permeable PFM is used as a substitute for the PEM. Due to the remarkable catalytic activity and the optimized resistance, the PFM-based DEFC exhibits encouraging performance, which can afford a peak power density of 47.4 mW cm−2 with a porous NiCo2O4 cathode catalyst. Moreover, it can operate continuously for 100 h with only 4.56% drop in electrical output. Therefore, this study provides a very effective strategy for optimizing DEFCs with low cost and high performance.
Ni-doped SnO 2 nanofiber array was prepared from a modified electrospinning technique followed with hot-press and calcination, which impart the nanofiber with high crystallinity as well as good adhesion to the substrate. The nanofiber array consists of well-aligned straight fibers with an average diameter of ∼200 nm and length of several millimeters. Each fiber consists of rutile-structured polycrystals with an average grain size of ∼5 nm. Conductometric gas sensors were developed from the nanofiber array using magnetron sputtering. These sensors show excellent performance for NO 2 detection at 250 °C, including high response (90.3 under 20 ppm), fast response and recovery (40 s/18 s), and above all, excellent selectivity. Beneficial for electron transport, the nanofiber array offers better device performance over random nanofibers on sensing response and time for recovery. In addition, the NO 2 sensing mechanism was probed with detailed DRIFT and XPS analysis.
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