In order to acquire LaNiO3 nanofibers with particular morphology and structure, electrospinning technique, for the first time, was successfully applied to fabricate LaNiO3 nanofibers in the paper. Polyvinyl alcohol（...In order to acquire LaNiO3 nanofibers with particular morphology and structure, electrospinning technique, for the first time, was successfully applied to fabricate LaNiO3 nanofibers in the paper. Polyvinyl alcohol（PVA）/ [La（NO3）3＋Ni（CH3COO）2] composite nanofibers were fabricated by electrospinning, and polycrystalline LaNiO3 nanofibers were prepared by calcination of the PVA/[La（NO3）3＋Ni（CH3COO）2] composite nanofibers at 6000C for 10 h. The samples were characterized by using thermogravimetric-differential thermal analysis （TG-DTA）, X-ray diffraction spectrometry（XRD）, scanning electron microscopy （SEM） and Fourier transform infrared spectrometry （FTIR）. The results showed that PVA/[La（NO3）3＋ Ni（CH3COO）2] composite nanofibers were amorphous in structure, and pure phase LaNiO3 nanofibers were trigonal with space group R3m. The surface of as-prepared composite nanofibers was smooth, and the diameter was about 200 nm. The diameter of LaNiO3 nanofibers was smaller than that of the relevant composite fibers. The surface of the LaNiO3 nanofibers becomes coarse with the increase of calcination temperatures. The diameter of LaNiO3 nanofibers was ca. 80 nm, and the length was greater than 100μm. The mass of the sample remained constant when the temperature was above 463℃, and the total mass loss percentage was 90.9%. Possible formation mechanism of LaNiO3 nanofibers was preliminarily proposed.展开更多
No-precious bifunctional catalysts with high electrochemical activities and stability were crucial to properties of rechargeable zinc-air batteries.Herein,LaNiO3 modified with Ag nanoparticles(Ag/LaNiO3)was prepared b...No-precious bifunctional catalysts with high electrochemical activities and stability were crucial to properties of rechargeable zinc-air batteries.Herein,LaNiO3 modified with Ag nanoparticles(Ag/LaNiO3)was prepared by the co-synthesis method and evaluated as the bifunctional oxygen catalyst for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).Compared with LaNiO3,Ag/LaNiO3 demonstrated the enhanced catalytic activity towards ORR/OER as well as higher limited current density and lower onset potential.Moreover,the potential gap between ORR potential(at-3 mA cm^-2)and OER potential(at 5 mA cm^-2)was 1.16 V.The maximum power density of the primary zinc-air battery with Ag/LaNiO3 catalyst achieved 60 mW cm^-2.Furthermore,rechargeable zinc-air batteries operated reversible charge-discharge cycles for 150 cycles without noticeable performance deterioration,which showed its excellent bifunctional activity and cycling stability as oxygen electrocatalyst for rechargeable zinc-air batteries.These results indicated that Ag/LaNiO3 prepared by the co-synthesis method was a promising bifunctional catalyst for rechargeable zinc-air batteries.展开更多
文摘In order to acquire LaNiO3 nanofibers with particular morphology and structure, electrospinning technique, for the first time, was successfully applied to fabricate LaNiO3 nanofibers in the paper. Polyvinyl alcohol（PVA）/ [La（NO3）3＋Ni（CH3COO）2] composite nanofibers were fabricated by electrospinning, and polycrystalline LaNiO3 nanofibers were prepared by calcination of the PVA/[La（NO3）3＋Ni（CH3COO）2] composite nanofibers at 6000C for 10 h. The samples were characterized by using thermogravimetric-differential thermal analysis （TG-DTA）, X-ray diffraction spectrometry（XRD）, scanning electron microscopy （SEM） and Fourier transform infrared spectrometry （FTIR）. The results showed that PVA/[La（NO3）3＋ Ni（CH3COO）2] composite nanofibers were amorphous in structure, and pure phase LaNiO3 nanofibers were trigonal with space group R3m. The surface of as-prepared composite nanofibers was smooth, and the diameter was about 200 nm. The diameter of LaNiO3 nanofibers was smaller than that of the relevant composite fibers. The surface of the LaNiO3 nanofibers becomes coarse with the increase of calcination temperatures. The diameter of LaNiO3 nanofibers was ca. 80 nm, and the length was greater than 100μm. The mass of the sample remained constant when the temperature was above 463℃, and the total mass loss percentage was 90.9%. Possible formation mechanism of LaNiO3 nanofibers was preliminarily proposed.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51372057 and 21373071).
文摘No-precious bifunctional catalysts with high electrochemical activities and stability were crucial to properties of rechargeable zinc-air batteries.Herein,LaNiO3 modified with Ag nanoparticles(Ag/LaNiO3)was prepared by the co-synthesis method and evaluated as the bifunctional oxygen catalyst for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).Compared with LaNiO3,Ag/LaNiO3 demonstrated the enhanced catalytic activity towards ORR/OER as well as higher limited current density and lower onset potential.Moreover,the potential gap between ORR potential(at-3 mA cm^-2)and OER potential(at 5 mA cm^-2)was 1.16 V.The maximum power density of the primary zinc-air battery with Ag/LaNiO3 catalyst achieved 60 mW cm^-2.Furthermore,rechargeable zinc-air batteries operated reversible charge-discharge cycles for 150 cycles without noticeable performance deterioration,which showed its excellent bifunctional activity and cycling stability as oxygen electrocatalyst for rechargeable zinc-air batteries.These results indicated that Ag/LaNiO3 prepared by the co-synthesis method was a promising bifunctional catalyst for rechargeable zinc-air batteries.
