Stable high current density operation of La0.6Sr0.4Co0.2Fe0.8O3−δ oxygen electrodes

2019 ◽  
Vol 7 (22) ◽  
pp. 13531-13539 ◽  
Author(s):  
Matthew Y. Lu ◽  
Justin G. Railsback ◽  
Hongqian Wang ◽  
Qinyuan Liu ◽  
Yvonne A. Chart ◽  
...  

Stable operation of LSCF oxygen electrodes with high current densities at high temperatures for solid oxide electrochemical cells.

Author(s):  
Takashi Fujikawa ◽  
Yoshitoshi Ogura ◽  
Koki Ishigami ◽  
Yoshihiro Kawano ◽  
Miyuki Nagamine ◽  
...  

Abstract Geobacter sulfurreducens produces high current densities and it has been used as a model organism for extracellular electron transfer studies. Nine G. sulfurreducens strains were isolated from biofilms formed on an anode poised at –0.2 V (vs. SHE) in a bioelectrochemical system in which river sediment was used as an inoculum. The maximum current density of an isolate, strain YM18 (9.29 A/m2), was higher than that of the strains PCA (5.72 A/m2), the type strain of G. sulfurreducens, and comparable to strain KN400 (8.38 A/m2), which is another high current producing strain of G. sulfurreducens. Genomic comparison of strains PCA, KN400, and YM18 revealed that omcB, xapD, spc, and ompJ, which are known to be important genes for iron reduction and current production in PCA, were not present in YM18. In the PCA and KN400 genomes, two and one region (s) encoding CRISPR/Cas systems were identified, respectively, but they were missing in the YM18 genome. These results indicate that there is genetic variation in the key components involved in extracellular electron transfer among G. sulfurreducens strains.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroyuki Shimada ◽  
Toshiaki Yamaguchi ◽  
Haruo Kishimoto ◽  
Hirofumi Sumi ◽  
Yuki Yamaguchi ◽  
...  

AbstractSolid oxide electrolysis cells can theoretically achieve high energy-conversion efficiency, but current density must be further increased to improve the hydrogen production rate, which is essential to realize widespread application. Here, we report a structure technology for solid oxide electrolysis cells to achieve a current density higher than 3 A cm−2, which exceeds that of state-of-the-art electrolyzers. Bimodal-structured nanocomposite oxygen electrodes are developed where nanometer-scale Sm0.5Sr0.5CoO3−δ and Ce0.8Sm0.2O1.9 are highly dispersed and where submicrometer-scale particles form conductive networks with broad pore channels. Such structure is realized by fabricating the electrode structure from the raw powder material stage using spray pyrolysis. The solid oxide electrolysis cells with the nanocomposite electrodes exhibit high current density in steam electrolysis operation (e.g., at 1.3 V), reaching 3.13 A cm−2 at 750 °C and 4.08 A cm−2 at 800 °C, corresponding to a hydrogen production rate of 1.31 and 1.71 L h−1 cm−2 respectively.


Author(s):  
Xiulin Yang ◽  
Defei Liu ◽  
Shenghong Zhong ◽  
Xiaofeng Zhou ◽  
Kuo-Wei Huang ◽  
...  

Selective conversion of CO2 to formate with high current densities is highly desirable but still challenging. Copper hollow fibers with interconnected pore structures were fabricated via a facile method and used as a stand-alone cathode for highly efficient electrochemical reduction of CO2 to formate. Our studies revealed that delivering the reactant CO2 gas to the inner space of the hollow fiber could build up a higher CO2 partial pressure in the pores and presumably reduce the concentration of H[Formula: see text] from the electrolyte to effectively suppress the major competing reaction, hydrogen evolution reaction (HER), from 46.9% faradaic efficiency (FE) to 15.0%. A high selectivity for CO2 reduction to formate with a maximum FE of 77.1% was achieved with a high current density of 34.7[Formula: see text]mA cm[Formula: see text], which is one of the highest FEs on Cu-based materials. Mechanistic studies suggest that the abundant active sites along with the unique crystal facets induced by the high pressure of CO2 at the pore surface in the “gas in” mode are attributed to the superior electroactivity and selectivity for the CO2 reduction to formate. The Cu hollow fiber electrodes exhibit an outstanding long-term stability at high current density, showing great potential for large-scale practical applications.


Although the spectrum of the ordinary carbon arc has been studied in great detail during the last 70 years, there seems to have been no similar study of the “High Current Density” arc which was introduced by Beck in 1914. Spectrophotometrical measurements have been made in connection with the development of this type of arc for searchlights, and photographs of the spectra obtained from the total radiation from the arc have been published. The only account, however, of the spectrum from individual parts of the arc appears in a short note by Bell and Bassett. They examined an image of the arc on a ground glass screen with a direct vision spectroscope and reported that in the arc stream 15 lines appeared when the current exceeded 100 amperes. They attributed 7 of these to helium and 2 to hydrogen.


Author(s):  
Chaoyang Sun ◽  
Hui Wang ◽  
Shan Ji ◽  
Xuyun Wang ◽  
Vladimir Linkov ◽  
...  

A layered FeCo double hydroxide bifunctional water cracking electrocatalyst with ultra-high stability at high current density was developed.


2020 ◽  
Vol 88 (4) ◽  
pp. 290-294
Author(s):  
Yuchao LI ◽  
Daan CUI ◽  
Huiying QI ◽  
Zhe ZHAO ◽  
Yibo GUO ◽  
...  

2013 ◽  
Vol 829 ◽  
pp. 451-455 ◽  
Author(s):  
Maryam Haeri far ◽  
Morteza Zandrahimi

In the present study 304 stainless steel (SS) was electrochemical plated with nanocrystallineMn-Cu alloy coatings from a bath containing ammonium sulfate.The electrochemical investigation of Mn-Cu electrodeposited films was managed by potentiodynamic scans and galvanostatic experiments. The effect of current density on the microstructure, crystallographic structure, and chemical composition of the deposits were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive x-ray spectrometry (EDS), respectively.The results showed that Mn-Cu coatings obtained at low current density contain a large amount of Cu and heterogeneous microstructure, while at high current density uniform, compact, and amorphous coatings with a small amount of Cu was obtained. The results indicated that Cu co-deposition delayed the phase transformation of as-deposited ductile γ-Mn to the brittle and hard α-Mn. However, the results did not show any specific changes in grain size of the coatings with variation of current densities.


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