Comparison Study of the Electrochemical Behavior of Vanadate in NaOH and KOH Solutions

2011 ◽  
Vol 402 ◽  
pp. 66-73
Author(s):  
Biao Liu ◽  
Shi Li Zheng ◽  
Hui Bin Liu ◽  
Hao Du ◽  
Shao Na Wang ◽  
...  
Keyword(s):  
Redox Reactions ◽  
Reduction Potential ◽  
Reduction Reaction ◽  
Carbon Electrode ◽  
Redox Behavior ◽  
Comparison Study ◽  
Oxidation Reactions ◽  
Reaction Conditions ◽  
Naoh Solution ◽  
Cyclic Voltammetry Method

The redox behavior of vanadate ions at glassy carbon electrode in KOH solutions with concentration ranging from 0.1M to 1M had been studied using cyclic voltammetry method. It is found out that vanadate ions experience similar redox reactions in both NaOH and KOH solutions, which involve a single cathodic reduction and two oxidation reactions in one cyclic sweep. Nearly same currents are obtained under the same reaction conditions in both solutions. However, vanadate ions appear more difficult to be reduced in KOH solutions than in NaOH solutions, and the reduction reaction exhibits higher irreversibility. The reduction potential is influenced by vanadate ions concentration, and is more negative in KOH solutions. The reversibility of reduction reaction is greatly dependent on alkalinity, and the reduction potential obviously decreases with the increase of alkalinity in KOH solutions. However, only a slight decrease was observed in NaOH solution, which may be due to the fact that OH-exhibits higher activity in KOH solutions.

One-pot Synthesis of Pyrazolone Sulfones by Iodine-catalyzed Sulfenylation of Pyrazolones with Aryl Sulfonyl Hydrazides Followed by Oxidation in Water

2018 ◽  
Vol 15 (3) ◽  
pp. 380-387
Author(s):  
Xia Zhao ◽  
Xiaoyu Lu ◽  
Lipeng Zhang ◽  
Tianjiao Li ◽  
Kui Lu
Keyword(s):  
Double Bond ◽  
Efficient Method ◽  
Room Temperature ◽  
Sulfonyl Chloride ◽  
Antibacterial Activities ◽  
Oxidation Reactions ◽  
Reaction Conditions ◽  
One Pot ◽  
X Ray ◽  
Amide Form

Aim and Objective: Pyrazolone sulfones have been reported to exhibit herbicidal and antibacterial activities. In spite of their good bioactivities, only a few methods have been developed to prepare pyrazolone sulfones. However, the substrate scope of these methods is limited. Moreover, the direct sulfonylation of pyrazolone by aryl sulfonyl chloride failed to give pyrazolone sulfones. Thus, developing a more efficient method to synthesize pyrazolone sulfones is very important. Materials and Method: Pyrazolone, aryl sulphonyl hydrazide, iodine, p-toluenesulphonic acid and water were mixed in a sealed tube, which was heated to 100°C for 12 hours. The mixture was cooled to 0°C and m-CPBA was added in batches. The mixture was allowed to stir for 30 min at room temperature. The crude product was purified by silica gel column chromatography to afford sulfuryl pyrazolone. Results: In all cases, the sulfenylation products were formed smoothly under the optimized reaction conditions, and were then oxidized to the corresponding sulfones in good yields by 3-chloroperoxybenzoic acid (m-CPBA) in water. Single crystal X-ray analysis of pyrazolone sulfone 4aa showed that the major tautomer of pyrazolone sulfones was the amide form instead of the enol form observed for pyrazolone thioethers. Moreover, the C=N double bond isomerized to form an α,β-unsaturated C=C double bond. Conclusion: An efficient method to synthesize pyrazolone thioethers by iodine-catalyzed sulfenylation of pyrazolones with aryl sulfonyl hydrazides in water was developed. Moreover, this method was employed to synthesize pyrazolone sulfones in one-pot by subsequent sulfenylation and oxidation reactions.

Trimetallic PtNiCo branched nanocages as efficient and durable bifunctional electrocatalysts towards oxygen reduction and methanol oxidation reactions

2021 ◽  
Author(s):  
hengrui Ma ◽  
Zhiping Zheng ◽  
Hongsheng Zhao ◽  
Cong Shen ◽  
Hanming Chen ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Methanol Oxidation ◽  
Oxidation Reaction ◽  
Reduction Reaction ◽  
Great Promise ◽  
Methanol Oxidation Reaction ◽  
Oxidation Reactions ◽  
Bifunctional Electrocatalysts ◽  
Composition And Structure

Engineering the composition and structure of Pt-based alloy electrocatalysts has exhibited great promise for enhancing activity and durability in oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR). However, it...

Durability study of platinum nanoparticles supported on gas-phase synthesized graphene in oxygen reduction reaction conditions

2019 ◽  
Vol 467-468 ◽  
pp. 1181-1186 ◽  
Author(s):  
Erwan Bertin ◽  
Adrian Münzer ◽  
Sven Reichenberger ◽  
Rene Streubel ◽  
Thomas Vinnay ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Gas Phase ◽  
Platinum Nanoparticles ◽  
Reduction Reaction ◽  
Reaction Conditions

scholarly journals Dioxygen dissociation over man-made system at room temperature to form the active α-oxygen for methane oxidation

2020 ◽  
Vol 6 (20) ◽  
pp. eaaz9776 ◽  
Author(s):  
Edyta Tabor ◽  
Jiri Dedecek ◽  
Kinga Mlekodaj ◽  
Zdenek Sobalik ◽  
Prokopis C. Andrikopoulos ◽  
...  
Keyword(s):  
Gas Phase ◽  
Room Temperature ◽  
Practical Importance ◽  
Oxidation Reactions ◽  
Reaction Conditions ◽  
Oxidation Of Methane ◽  
Oxidation Properties ◽  
Enzyme Functionality ◽  
Methane Utilization ◽  
Selective Oxidation Reactions

Activation of dioxygen attracts enormous attention due to its potential for utilization of methane and applications in other selective oxidation reactions. We report a cleavage of dioxygen at room temperature over distant binuclear Fe(II) species stabilized in an aluminosilicate matrix. A pair of formed distant α-oxygen species [i.e., (Fe(IV)═O)2+] exhibits unique oxidation properties reflected in an outstanding activity in the oxidation of methane to methanol at room temperature. Designing a man-made system that mimicks the enzyme functionality in the dioxygen activation using both a different mechanism and structure of the active site represents a breakthrough in catalysis. Our system has an enormous practical importance as a potential industrial catalyst for methane utilization because (i) the Fe(II)/Fe(IV) cycle is reversible, (ii) the active Fe centers are stable under the reaction conditions, and (iii) methanol can be released to gas phase without the necessity of water or water-organic medium extraction.

A Comparative Study on Ternary Low-Platinum Catalysts with Various Constructions for Oxygen Reduction and Methanol Oxidation Reactions

NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650081 ◽  
Author(s):  
Yan Ni Wu ◽  
Hai Fu Guo ◽  
Peng Hu ◽  
Xiao Peng Xiao ◽  
Zhao Wang Xiao ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Methanol Oxidation ◽  
Reduction Reaction ◽  
Methanol Oxidation Reaction ◽  
Core Shell ◽  
Oxidation Reactions ◽  
X Ray Diffraction ◽  
Structured Catalyst ◽  
Transmission Electron ◽  
One Step

Three types of ternary low-platinum nanocatalysts, alloy PdPtIr/C, core–shell PdPt@PtIr/C and Pd@PtIr/C, have been prepared, and their catalytic behaviors toward methanol oxidation reaction (MOR)/oxygen reduction reaction (ORR) are comparatively investigated via cyclic voltammetry and chronoamperometry analysis in an acidic medium. Through a two-step colloidal technique, the synthesized core–shell structured catalyst PtPd@PtIr/C with alloy core and alloy shell show the best catalytic activity toward MOR and the best poisoning tolerance. The alloy PdPtIr/C catalyst prepared via a one-step colloidal technique exhibits the best performance toward ORR among the three catalysts. All the three catalysts are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and other characterization techniques.

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