A robust iron oxyhydroxide water oxidation catalyst operating under near neutral and alkaline conditions

2016 ◽  
Vol 4 (10) ◽  
pp. 3655-3660 ◽  
Author(s):  
Debarati Roy Chowdhury ◽  
Leone Spiccia ◽  
S. S. Amritphale ◽  
Amit Paul ◽  
Archana Singh
Keyword(s):  
Thin Films ◽  
Water Oxidation ◽  
Metal Ion ◽  
Oxidation Catalyst ◽  
Iron Oxyhydroxide ◽  
Alkaline Ph ◽  
Inorganic Complexes ◽  
Electrochemically Deposited ◽  
Alkaline Conditions ◽  
Ph Conditions

Iron oxyhydroxide thin films electrochemically deposited from a non-aqueous medium using metal inorganic complexes as a metal ion precursor have been demonstrated as an efficient electrochemical water oxidation catalyst under near neutral as well as alkaline pH conditions.

Annealing temperature dependent catalytic water oxidation activity of iron oxyhydroxide thin films

2017 ◽  
Vol 26 (4) ◽  
pp. 757-761 ◽  
Author(s):  
P.T. Babar ◽  
B.S. Pawar ◽  
A.C. Lokhande ◽  
M.G. Gang ◽  
J.S. Jang ◽  
...  
Keyword(s):  
Thin Films ◽  
Water Oxidation ◽  
Annealing Temperature ◽  
Iron Oxyhydroxide ◽  
Temperature Dependent ◽  
Oxidation Activity

scholarly journals A Tetranuclear Cobalt (II) Phosphate Possessing a D4R Core: An Efficient Water Oxidation Catalyst

2019 ◽  
Author(s):  
Atanu Dey ◽  
Virendra Kumar ◽  
Shubhadeep Pal ◽  
Anku Guha ◽  
Sumit Bawari ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Density Functional ◽  
Oxidation Catalyst ◽  
Phosphate Ester ◽  
Durability Test ◽  
Efficient Catalyst ◽  
Functional Theory ◽  
Faradaic Efficiency ◽  
Alkaline Conditions ◽  
Current Densities

<p>The reaction of Co(OAc)<sub>2</sub>·4H<sub>2</sub>O with the sterically hindered phosphate ester, LH<sub>2</sub>, afforded the tetranuclear complex, [Co<sup>II</sup>(L)(CH<sub>3</sub>CN)]<sub>4</sub>∙5CH<sub>3</sub>CN (<b>1</b>) [LH<sub>2</sub> = <a>2,6</a>‐(diphenylmethyl)‐4‐isopropyl‐phenyl phosphate]. The molecular structure of <b>1</b> reveals that it is a tetranuclear assembly where the Co(II) centers are present in the alternate corners of a cube. The four Co(II) centers are held together by four di-anionic [L]<sup>2-</sup> ligands. The fourth coordination site on Co(II) is taken by an acetonitrile ligand. Changing the Co(II) precursor from Co(OAc)<sub>2</sub>·4H<sub>2</sub>O to Co(NO<sub>3</sub>)<sub>2</sub>.6H<sub>2</sub>O afforded the mononuclear complex [Co<sup>II</sup>(LH)<sub>2</sub>(CH<sub>3</sub>CN)<sub>2</sub>(MeOH)<sub>2</sub>](MeOH)<sub>2 </sub>(<b>2). </b>In<b> 2, </b>the Co(II) is surrounded by two monoanionic [LH]<sup>‒</sup> ligands, and a pair of methanol and acetonitrile solvents in a six-coordinate arrangement. <b>1</b> has been found to be an efficient catalyst for the electrochemical water oxidation under high basic conditions while the mononuclear analogue, <b>2</b>, does not respond towards electrochemical water oxidation. The tetranuclear catalyst has excellent electrochemcial stability and longevity, as established by the chronoamperometry and >1000 cycles durability test in high alkaline conditions. Excellent current densities of 1 and 10 mAcm<sup>‒2</sup> were achieved with the overpotential of 354 and 452 mV respectively. The turnover frequency of this catalyst was calculated as 5.23 s<sup>−1 </sup>with excellent faradaic efficiency of 97%, indicating the selective oxygen evolution (OER) process happening with the aid of this catalyst. A mechanistic insight in to the higher activity of complex <b>1</b> towards OER compared to complex <b>2 </b>is also provided with the help of density functional theory based calculations.</p>

scholarly journals A Tetranuclear Cobalt (II) Phosphate Possessing a D4R Core: An Efficient Water Oxidation Catalyst

2019 ◽  
Author(s):  
Atanu Dey ◽  
Virendra Kumar ◽  
Shubhadeep Pal ◽  
Anku Guha ◽  
Sumit Bawari ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Density Functional ◽  
Oxidation Catalyst ◽  
Phosphate Ester ◽  
Durability Test ◽  
Efficient Catalyst ◽  
Functional Theory ◽  
Faradaic Efficiency ◽  
Alkaline Conditions ◽  
Current Densities

<p>The reaction of Co(OAc)<sub>2</sub>·4H<sub>2</sub>O with the sterically hindered phosphate ester, LH<sub>2</sub>, afforded the tetranuclear complex, [Co<sup>II</sup>(L)(CH<sub>3</sub>CN)]<sub>4</sub>∙5CH<sub>3</sub>CN (<b>1</b>) [LH<sub>2</sub> = <a>2,6</a>‐(diphenylmethyl)‐4‐isopropyl‐phenyl phosphate]. The molecular structure of <b>1</b> reveals that it is a tetranuclear assembly where the Co(II) centers are present in the alternate corners of a cube. The four Co(II) centers are held together by four di-anionic [L]<sup>2-</sup> ligands. The fourth coordination site on Co(II) is taken by an acetonitrile ligand. Changing the Co(II) precursor from Co(OAc)<sub>2</sub>·4H<sub>2</sub>O to Co(NO<sub>3</sub>)<sub>2</sub>.6H<sub>2</sub>O afforded the mononuclear complex [Co<sup>II</sup>(LH)<sub>2</sub>(CH<sub>3</sub>CN)<sub>2</sub>(MeOH)<sub>2</sub>](MeOH)<sub>2 </sub>(<b>2). </b>In<b> 2, </b>the Co(II) is surrounded by two monoanionic [LH]<sup>‒</sup> ligands, and a pair of methanol and acetonitrile solvents in a six-coordinate arrangement. <b>1</b> has been found to be an efficient catalyst for the electrochemical water oxidation under high basic conditions while the mononuclear analogue, <b>2</b>, does not respond towards electrochemical water oxidation. The tetranuclear catalyst has excellent electrochemcial stability and longevity, as established by the chronoamperometry and >1000 cycles durability test in high alkaline conditions. Excellent current densities of 1 and 10 mAcm<sup>‒2</sup> were achieved with the overpotential of 354 and 452 mV respectively. The turnover frequency of this catalyst was calculated as 5.23 s<sup>−1 </sup>with excellent faradaic efficiency of 97%, indicating the selective oxygen evolution (OER) process happening with the aid of this catalyst. A mechanistic insight in to the higher activity of complex <b>1</b> towards OER compared to complex <b>2 </b>is also provided with the help of density functional theory based calculations.</p>

scholarly journals A Study of Catechin Photostability Using Photolytic Processing

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 293
Author(s):  
Jeu-Ming P. Yuann ◽  
Shwu-Yuan Lee ◽  
Meei-Ju Yang ◽  
Shiuh-Tsuen Huang ◽  
Chien-Wei Cheng ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Alkaline Solutions ◽  
Light Illumination ◽  
Drug Resistant ◽  
Alkaline Ph ◽  
Radical Species ◽  
Alkaline Conditions ◽  
Photolytic Reaction

Catechin exhibits numerous physiological characteristics. In this study, we determined the photosensitivity of catechin to various lights under alkaline conditions, and the mechanisms by which catechin generates free radical species and polymerizes via a photoreaction. In addition to this, the application of catechin photolysis was investigated. A solution of catechin is transparent, but turns yellowish under blue light illumination (BLI) in neutral or weak alkaline solutions. When catechin is subjected to BLI, a dimeric catechin (proanthocyanidin) and a superoxide anion radical (O2•−) are generated in a photolytic reaction. When ascorbic acid or gallic acid is added to catechin and the mixture is subjected to BLI at alkaline pH, fewer catechin dimers and less O2•− are produced, because both acids inhibit the photosensitive oxidation of catechin. When AlCl3 is added to catechin and the mixture is subjected to BLI at pH 8, a photolytic reaction is suppressed by AlCl3, and AlCl3 acts as a catalyst for the disconnection of proanthocyanidin during photolysis. Under alkaline conditions, catechin generates O2•− via photosensitive oxidation, which suppresses the growth of Acinetobacter baumannii (A. baumannii) by at least 4 logs, and deactivates its multi-drug-resistant strain. This study shows that catechin photolysis is a process of oxidation, and that it can be safely applied as a tool for environmental applications.

The effect of complexing agents in chemical solution deposition of metal chalcogenide thin films

2021 ◽  
Author(s):  
Sucheta Sengupta ◽  
Rinki Aggarwal ◽  
Yuval Golan
Keyword(s):  
Thin Films ◽  
Chemical Solution Deposition ◽  
Metal Ion ◽  
Chemical Deposition ◽  
Review Article ◽  
Complexing Agents ◽  
Chemical Solution ◽  
Solution Deposition ◽  
Metal Chalcogenide ◽  
Chalcogenide Thin Films

This review article gives an overview of different complexing agents used during chemical deposition of metal chalcogenide thin films and their role in controlling the resultant morphology by effective complexation of the metal ion.

Potential of arsenic bioremediation by a cyanobacterium isolated from the Salado River in the Atacama Desert

2021 ◽  
Vol 43 (2) ◽  
pp. 156-160
Author(s):  
Pablo Pérez-Portilla ◽  
Juan Araya ◽  
Karem Gallardo ◽  
Adriana Aránguiz-Acuña
Keyword(s):  
Atacama Desert ◽  
Aquatic Systems ◽  
Arid Environments ◽  
Northern Chile ◽  
Evolutionary Mechanisms ◽  
Alkaline Conditions ◽  
Ph Conditions ◽  
Removal Of Arsenic ◽  
Salado River ◽  
Over Time

Abstract Cyanobacteria and microalgae are recognized as excellent metal(loid)s-bioremediators of aquatic systems. We isolated a cyanobacterium from the Salado River in the Atacama Desert, northern Chile, which was identified as Cyanobium sp. Growth inhibition bioassays were conducted with arsenic and cadmium, and tolerance of Cyanobium to these metals was estimated. Removal of arsenic was assessed under different pH conditions and over time. We showed that the Cyanobium strain isolated from the Salado River has a greater tolerance to the arsenic and cadmium compounds than other species commonly used in metal(loid)s-bioremediation. Removal of up to 90% of arsenic was obtained in alkaline conditions, within the first 3 hours of exposure suggesting that Cyanobium sp. isolated from the Atacama Desert could be further studied with biotechnological purposes and to understand the evolutionary mechanisms of adaption to arid environments.

Water Oxidation Catalyst via Heterogenization of Iridium Oxides on Silica: A Polyamine-Mediated Route To Achieve Activity and Stability

ACS Catalysis ◽  
2016 ◽  
Vol 6 (9) ◽  
pp. 5699-5705 ◽  
Author(s):  
Nagaraju Shilpa ◽  
Joydeb Manna ◽  
Parasmani Rajput ◽  
Rohit Kumar Rana
Keyword(s):  
Water Oxidation ◽  
Oxidation Catalyst ◽  
Iridium Oxides

scholarly journals Direct measurement of the thermoelectric properties of electrochemically deposited Bi2Te3 thin films

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jose Recatala-Gomez ◽  
Pawan Kumar ◽  
Ady Suwardi ◽  
Anas Abutaha ◽  
Iris Nandhakumar ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermoelectric Properties ◽  
Bismuth Telluride ◽  
Indium Tin Oxide ◽  
Seed Layer ◽  
Room Temperature ◽  
Low Cost ◽  
Temperature Dependent ◽  
Temperature Heat ◽  
Electrochemically Deposited

Abstract The best known thermoelectric material for near room temperature heat-to-electricity conversion is bismuth telluride. Amongst the possible fabrication techniques, electrodeposition has attracted attention due to its simplicity and low cost. However, the measurement of the thermoelectric properties of electrodeposited films is challenging because of the conducting seed layer underneath the film. Here, we develop a method to directly measure the thermoelectric properties of electrodeposited bismuth telluride thin films, grown on indium tin oxide. Using this technique, the temperature dependent thermoelectric properties (Seebeck coefficient and electrical conductivity) of electrodeposited thin films have been measured down to 100 K. A parallel resistor model is employed to discern the signal of the film from the signal of the seed layer and the data are carefully analysed and contextualized with literature. Our analysis demonstrates that the thermoelectric properties of electrodeposited films can be accurately evaluated without inflicting any damage to the films.

Sign in / Sign up

Export Citation Format

Share Document