A Superlattice of Alternately Stacked Ni–Fe Hydroxide Nanosheets and Graphene for Efficient Splitting of Water

ACS Nano ◽  
2015 ◽  
Vol 9 (2) ◽  
pp. 1977-1984 ◽  
Author(s):  
Wei Ma ◽  
Renzhi Ma ◽  
Chengxiang Wang ◽  
Jianbo Liang ◽  
Xiaohe Liu ◽  
...  
Keyword(s):  
Fe Hydroxide

scholarly journals Microbial nitrification and acidification of lacustrine sediments deduced from the nature of a sedimentary kaolin deposit in central Japan

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tetsuichi Takagi ◽  
Ki-Cheol Shin ◽  
Mayumi Jige ◽  
Mihoko Hoshino ◽  
Katsuhiro Tsukimura
Keyword(s):  
Nitric Acid ◽  
Lacustrine Sediments ◽  
Kaolin Clay ◽  
Central Japan ◽  
Inland Lakes ◽  
Fe Oxidation ◽  
Stable Isotopic ◽  
Fe Hydroxide ◽  
Kaolin Deposit ◽  
Dilute Nitric Acid

AbstractKaolin deposits in the Seto-Tono district, central Japan, were formed by intense kaolinization of lacustrine arkose sediments deposited in small and shallow inland lakes in the late Miocene. Based on mineralogical and stable isotopic (Fe, C, N) studies of Motoyama kaolin deposit in the Seto area, we concluded that it was formed by microbial nitrification and acidification of lacustrine sediments underneath an inland lake. Small amounts of Fe–Ti oxides and Fe-hydroxide in the kaolin clay indicated that iron was oxidized and leached during the kaolinization. The field occurrences indicate that leached ferric iron precipitated on the bottom of the kaolin deposit as limonite crusts, and their significantly fractionated Fe isotope compositions suggest the involvement of microbial activity. The C/N ratios of most of the kaolin clay are distinctly higher than those of modern lacustrine sediment. Although, the possibility of a low-temperature hydrothermal origin of the kaolin deposit cannot be completely ruled out, it is more likely that acidification by dilute nitric acid formed from plant-derived ammonia could have caused the kaolinization, Fe oxidation and leaching. The nitrate-dependent microbial Fe oxidation is consistent with dilute nitric acid being the predominant oxidant.

Treatment of As(V) and As(III) by electrocoagulation using Al and Fe electrode

2009 ◽  
Vol 60 (5) ◽  
pp. 1341-1346 ◽  
Author(s):  
W. H. Kuan ◽  
C. Y. Hu ◽  
M. C. Chiang
Keyword(s):  
Passive Film ◽  
Potentiodynamic Polarization ◽  
Electrode Materials ◽  
Initial Period ◽  
Electrode System ◽  
Initial Solution ◽  
Alkaline Condition ◽  
Bipolar Electrode ◽  
Pitting Potential ◽  
Fe Hydroxide

A batch electrocoagulation (EC) process with bipolar electrode and potentiodynamic polarization tests with monopolar systems were investigated as methods to explore the effects of electrode materials and initial solution pH on the As(V) and As(III) removal. The results displayed that the system with Al electrode has higher reaction rate during the initial period from 0 to 25 minutes than that of Fe electrode for alkaline condition. The pH increased with the EC time because the As(V) and As(III) removal by either co-precipitation or adsorption resulted in that the OH positions in Al-hydroxide or Fe-hydroxide were substituted by As(V) and As(III). The pH in Fe electrode system elevate higher than that in Al electrode because the As(V) removal substitutes more OH position in Fe-hydroxide than that in Al-hydroxide. EC system with Fe electrode can successfully remove the As(III) but system with Al electrode cannot because As(III) can strongly bind to the surface of Fe-hydroxide with forming inner-sphere species but weakly adsorb to the Al-hydroxide surface with forming outer-sphere species. The acidic solution can destroy the deposited hydroxide passive film then allow the metallic ions liberate into the solution, therefore, the acidic initial solution can enhance the As(V) and As(III) removal. The over potential calculation and potentiodynamic polarization tests reveal that the Fe electrode systems possess higher over potential and pitting potential than that of Al electrode system due to the fast hydrolysis of and the occurrence of Fe-hydroxide passive film.

scholarly journals Ultrathin Co–Fe hydroxide nanosheet arrays for improved oxygen evolution during water splitting

RSC Advances ◽  
2017 ◽  
Vol 7 (37) ◽  
pp. 22818-22824 ◽  
Author(s):  
Tingting Zhou ◽  
Zhen Cao ◽  
Heng Wang ◽  
Zhen Gao ◽  
Long Li ◽  
...  
Keyword(s):  
Surface Area ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Active Sites ◽  
Three Dimensional ◽  
Fe Doping ◽  
Nanosheet Arrays ◽  
Fe Hydroxide

The Fe-doping of hierarchical Co hydroxide nanosheet arrays (CoyFe1−y(OH)x NSAs) integrated on a three-dimensional electrode is shown to contribute to both increasing the available surface area and number of active sites.

A systematic approach to achieve high energy density hybrid supercapacitors based on Ni–Co–Fe hydroxide

2020 ◽  
Vol 353 ◽  
pp. 136578
Author(s):  
Su Chan Lee ◽  
Shude Liu ◽  
Pragati A. Shinde ◽  
Kyung Yoon Chung ◽  
Seong Chan Jun
Keyword(s):  
Energy Density ◽  
Systematic Approach ◽  
High Energy ◽  
High Energy Density ◽  
Hybrid Supercapacitors ◽  
Fe Hydroxide

Phosphate Bonding on Noncrystalline Al/Fe-Hydroxide Coprecipitates

2011 ◽  
Vol 45 (15) ◽  
pp. 6283-6289 ◽  
Author(s):  
Yu-Ting Liu ◽  
Dean Hesterberg
Keyword(s):  
Phosphate Bonding ◽  
Fe Hydroxide

Ultrafast Electrodeposition of Ni−Fe Hydroxide Nanosheets on Nickel Foam as Oxygen Evolution Anode for Energy-Saving Electrolysis of Na2 CO3 /NaHCO3

2017 ◽  
Vol 4 (5) ◽  
pp. 1044-1050 ◽  
Author(s):  
Yanzhi Sun ◽  
Chunxiang Liu ◽  
Linying Zhang ◽  
Pingyu Wan ◽  
Shuxian Zhuang ◽  
...  
Keyword(s):  
Energy Saving ◽  
Oxygen Evolution ◽  
Nickel Foam ◽  
Fe Hydroxide

A Green Pre-Film for Carbon Steel by Cerium Salt in Seawater

2012 ◽  
Vol 538-541 ◽  
pp. 72-77
Author(s):  
Li Li Gao ◽  
Zheng Zhang ◽  
Wei Zhen Wang ◽  
Xiang Yu Hou ◽  
Jing Wang ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Protective Layer ◽  
Processing Parameters ◽  
Forming Process ◽  
Effective Protection ◽  
Environment Friendly ◽  
Orthogonal Experiments ◽  
Digital Microscope ◽  
Cerium Salt ◽  
Fe Hydroxide

An environment-friendly pre-film for carbon steel was obtained by using seawater with cerium salt. The influencing factors of cerium salt pre-film were discussed through orthogonal experiments, and the optimum processing parameters were confirmed. Then morphology, composition, the forming process and corrosion resistance of the pre-film were investigated. Analysis by digital microscope showed that the cerium salt pre-film was a blue uniform coating. EDS images displayed that the pre-film consisted of Ce, O and Fe, the major component of the protective layer was a mixture of Ce oxide, Ce hydroxide and Fe hydroxide. The results of electrochemical potentiodynamic polarization and gravimetric measurements indicated that the cerium salt pre-film provided effective protection to the substrate of carbon steel.

Modelling the speciation pattern of metals in Ondo coastal water with geochemical model – PHREEQCI

2012 ◽  
Vol 7 (3) ◽  
Author(s):  
Foluso O. Agunbiade ◽  
Bamidele I. Olu-Owolabi ◽  
Kayode O. Adebowale
Keyword(s):  
Coastal Water ◽  
Toxic Metals ◽  
Quality Parameters ◽  
Geochemical Model ◽  
Free Ion ◽  
Speciation Modelling ◽  
High Alkalinity ◽  
Ondo State ◽  
Fe Hydroxide ◽  
Ion Species

The speciation pattern of ten metals was studied in the coastal water of Ondo State, Nigeria using geochemical modelling software (PHREEQCI). The metals classified as macronutrients – Na, Ca, K, Mg; micronutrients – Fe, Cu, Mn, Zn; toxic metals – Cd, Pb were evaluated along with other general water quality parameters from ten sampling sites. The results served as input data for the modelling. The outcomes of the water speciation modelling revealed that the macronutrient metals exist as free ions which aid the reduction of free ion species of toxic metals. The micronutrients exist as neutral or complex salts which are less toxic according to free ion activity model theory. The self purification capacity of the coastal water was aided by the abundant formation of Fe-hydroxide precipitates; high alkalinity; pH; salinity of the coastal water which are responsible for the reduction of free ion specie of Pb and its ecotoxicity but increased the concentration of toxic Cd chloride species. Therefore, the prevailing biogeochemistry of the coast enhances demobilization of the metal contaminants and favours the reduction of their toxicity except Cd.

scholarly journals Valence Alignment of Mixed Ni–Fe Hydroxide Electrocatalysts through Preferential Templating on Graphene Edges for Enhanced Oxygen Evolution

ACS Nano ◽  
2020 ◽  
Vol 14 (9) ◽  
pp. 11327-11340
Author(s):  
Constantine Tsounis ◽  
Xunyu Lu ◽  
Nicholas M. Bedford ◽  
Bijil Subhash ◽  
Lars Thomsen ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Fe Hydroxide
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