Evaluation of a molybdenum sulfide reference electrode in hot alkaline solutions

TAPPI Journal ◽  
2010 ◽  
Vol 9 (7) ◽  
pp. 35-41
Author(s):  
OUTI A. HYÖKYVIRTA ◽  
TOM E. GUSTAFSSON
Keyword(s):  
Molybdenum Disulfide ◽  
Surface Film ◽  
Reference Electrode ◽  
Exposure Period ◽  
Molybdenum Sulfide ◽  
Alkaline Solutions ◽  
Internal Reference ◽  
Cell Potential ◽  
Pulp Digester ◽  
Alkaline Sulfide

This investigation evaluated the applicability of a molybdenum sulfide reference electrode (MSRE) as an internal reference electrode for use in alkaline sulfide solutions over a range of pulp digester liquors at 170°C. The electrode remained stable during the exposure period of two weeks. The experimentally determined half cell potential of the MSRE is E = -0.91 VSHE. The surface of the MSRE was examined by scanning electron microscope (SEM) and electron spectroscopy for chemical analysis (ESCA) to verify the chemical composition of the thin surface film. Based on ESCA studies, the surface film contained molybdenum disulfide and sodium disulfide. During storage of the specimens, sulfide was partly oxidized to sodium sulfite in air. Next to the metallic molybdenum, a mixed molybdenum disulfide and molybdenum hydroxide layer was detected.

scholarly journals Mechanisms of passivation and chloride-induced corrosion of mild steel in sulfide-containing alkaline solutions

2021 ◽  
Author(s):  
Shishir Mundra ◽  
John L. Provis
Keyword(s):  
Mild Steel ◽  
Surface Film ◽  
Critical Role ◽  
Chloride Concentration ◽  
Alkaline Solutions ◽  
Sulfide Concentration ◽  
Chloride Induced Corrosion ◽  
Alkaline Sulfide ◽  
High Sulfide

AbstractThe pore fluid within many concretes is highly alkaline and rich in reduced sulfur species, but the influence of such alkaline-sulfide solutions on the surface film formed on steel reinforcement is poorly understood. This study investigates the critical role of HS− in defining mild steel passivation chemistry. The surface film formed on the steel in alkaline-sulfide solutions contains Fe(OH)2 and Fe–S complexes, and the critical chloride concentration to induce corrosion increases at high sulfide concentration. However, this behavior is dependent on the duration of exposure of the steel to the electrolyte, and the nature of the sulfidic surface layer.

Guidelines for potentiometric measurements in suspensions Part B. Guidelines for practical pH measurements in soil suspensions (IUPAC Recommendations 2006)

2007 ◽  
Vol 79 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Srecko F. Oman ◽  
M. Filomena Camões ◽  
Kipton J. Powell ◽  
Raj Rajagopalan ◽  
Petra Spitzer
Keyword(s):  
Reference Electrode ◽  
Operational Definition ◽  
Indicator Electrode ◽  
Liquid Junction ◽  
Cell Potential ◽  
Technical Report ◽  
Potentiometric Measurements ◽  
Suspension Effect ◽  
The Difference ◽  
Definition Of

The measured cell potentials for suspension potentiometric cells have been interpreted and explained by a detailed analysis of the schemes for these cells ["Guidelines for potentiometric measurements in suspensions. Part A. The suspension effect (IUPAC Technical Report", Pure Appl. Chem.79, 67 (2007)]. Some former disagreements amongst investigations have been clarified. A new unambiguous operational definition of the suspension effect (SE) is presented. It is defined as the difference in cell potential for two suspension potentiometric cells, one with both electrodes in the separated equilibrium solution (eqs) and the other with both electrodes in the sediment or suspension. This potential difference is the sum of the change in the indicator electrode (IE) potential and the change in the liquid junction potential of the reference electrode (RE), when the electrodes are used for measurement, once in the sediment of the suspension and then in its eqs.

scholarly journals THE PREPARATION OF AN IODATE SELECTIVE ELECTRODE USING SILVER IODATE AS THE ACTIVE AGENT IN A CHITOSAN SUPPORT

2010 ◽  
Vol 7 (3) ◽  
pp. 284-287
Author(s):  
Ani Mulyasuryani ◽  
Qonitah Fardiyah ◽  
Rizki Sugiri
Keyword(s):  
Detection Limit ◽  
Response Time ◽  
Active Agent ◽  
Reference Electrode ◽  
Chitosan Solution ◽  
Precipitation Reaction ◽  
Selective Electrode ◽  
Cell Potential ◽  
Chitosan Membrane ◽  
Electrode Cell

The iodate-selective electrode based on the principle of precipitation reaction could be made by coating the platinum wire with silver iodate (AgIO3). In this research was carried out optimization the iodate-selective electrode using chitosan membrane as an AgIO3 support. The AgIO3 were added in the 2 mL 1% chitosan solution, is 0.5 to 2.5 % (w/v). The thickness of the membrane used is 6 to 12 µm. The electrode cell potential is measured against Ag/AgCl electrode as a reference electrode. The optimum electrode performance was at 2.0 % of AgIO3 with thickness a membrane of 10 µm. The iodate-selective electrode has a Nernstian factor is 52.96 mV/decade and a response time of 10 seconds. The concentration range was determined from 10-3 M to 10-1 M and the detection limit is 1.12 x 10-5 M.   Keywords:  Ion Selective Electrode, Iodate, Chitosan Membrane

Properties of Copper and Molybdenum Sulfide Powders Produced by Self-Propagating High-Temperature Synthesis

2013 ◽  
Vol 872 ◽  
pp. 191-196 ◽  
Author(s):  
Farabi Bozheyev ◽  
Vladimir V. An ◽  
Yuriy Irtegov
Keyword(s):  
High Temperature ◽  
Molybdenum Disulfide ◽  
Copper Sulfide ◽  
Average Particle Size ◽  
Electrical Explosion ◽  
Molybdenum Sulfide ◽  
Average Particle ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Electrical Explosion Of Wires

Copper and molybdenum sulfide nanopowders were prepared by self-propagating high-temperature synthesis in argon. The initial copper powder and molybdenum powder were produced by electric spark dispersion in hexane and by electrical explosion of wires (EEW) in argon, respectively. The powders were studied by electron microscopy, X-ray diffraction and Raman spectroscopy. The copper sulfide main phase is hexagonal 2H-CuS, whereas hexagonal 2H-MoS2 and rhombohedral 3R-MoS2 are characteristic for molybdenum disulfide. The lattice parameters of copper and molybdenum sulfides were calculated. The average particle size of copper sulfide and molybdenum disulfide powders was about 50 nm and 80 nm, respectively.

The electrochemical formation of mercuric oxide in alkaline solution

1978 ◽  
Vol 56 (3) ◽  
pp. 336-342 ◽  
Author(s):  
Remigio Germano Barradas ◽  
Stephen Fletcher ◽  
John Douglas Porter
Keyword(s):  
Computer Simulations ◽  
Growth Mechanism ◽  
Model Test ◽  
Alkaline Solution ◽  
Reference Electrode ◽  
Electrode System ◽  
Alkaline Solutions ◽  
Mercuric Oxide ◽  
Derived Data ◽  
Theoretical Developments

The electrochemical formation of mercuric oxide on mercury in alkaline solutions is described. The reaction was investigated because of its importance as a reference electrode system, and also because it provides a model test of recent theoretical developments. Various derived data are compared to computer simulations of the growth mechanism.

Corrosion Testing by Measurement of Local Cell Potentials★

CORROSION ◽  
1954 ◽  
Vol 10 (1) ◽  
pp. 25-29 ◽  
Author(s):  
J. K. RICE
Keyword(s):  
Corrosion Inhibition ◽  
Reference Electrode ◽  
Water Systems ◽  
Corrosion Testing ◽  
Cell Potential ◽  
Rotating Electrode ◽  
Corrosion Rates ◽  
Local Cell

Abstract The method of studying corrosion rates by measuring the local cell potential using a rotating electrode and stationary micro-probe reference electrode is briefly reviewed. The results are presented of applying the method to the study of the effect of different variables on the corrosion inhibition properties of hexametaphosphate on steel in aerated water systems.

scholarly journals Interfacial Electronic Structure Engineering on Molybdenum Sulfide for Robust Dual-pH Hydrogen Evolution

2021 ◽  
Author(s):  
Mingqiang Liu ◽  
Jia-ao Wang ◽  
Gui-Gen Wang ◽  
Fei Li ◽  
Ya-Wei Cai ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Molybdenum Disulfide ◽  
Hydrogen Evolution ◽  
Metallic Phase ◽  
Molybdenum Sulfide ◽  
Interfacial Chemistry ◽  
Surface Electronic Structure ◽  
Interfacial Electronic Structure ◽  
Tafel Slopes ◽  
Structure Engineering

Abstract Molybdenum disulfide, as an electronic highly-adjustable catalysts material, tuning its electronic structure is crucial to enhance its intrinsic hydrogen evolution reaction (HER) activity. Nevertheless, there are yet huge challenges to the understanding and regulation of the surface electronic structure of molybdenum disulfide-based catalysts. Here we address these challenges by tuning its electronic structure of phase modulation synergistic with interfacial chemistry and defects from phosphorus or sulfur implantation, and we then successfully design and synthesize electrocatalysts with the multi-heterojunction interfaces (e.g., 1T0.81-MoS2@Ni2P), demonstrating superior HER activities and good stabilities with a small overpotentials of 38.9 and 98.5 mV at 10 mA/cm2, a low Tafel slopes of 41 and 42 mV/dec in acidic as well as alkaline surroundings, outperforming commercial Pt/C catalyst and other reported Mo-based catalysts. Theoretical calculation verified that the incorporation of metallic-phase and intrinsic HER-active Ni-based materials into molybdenum disulfide could effectively regulate its electronic structure for making the bandgap narrower. Additionally, reduced nickel possesses empty orbitals, which is helpful for additional H binding ability. All these factors can decrease Mo-H bond strength, greatly improving the HER catalytic activity of these materials.

scholarly journals OPTIMIZATION OF SCREEN PRINTED REFERENCE ELECTRODE BASED ON CHARGE BALANCE AND POLY (BUTYL ACRYLATE) PHOTOCURABLE MEBRANE

2016 ◽  
Vol 2 (1) ◽  
pp. 10 ◽  
Author(s):  
S. Alva ◽  
L. Y. Heng ◽  
M. Ahmad
Keyword(s):  
Solid State ◽  
Reference Electrode ◽  
Potassium Ions ◽  
Charge Balance ◽  
Optimum Ratio ◽  
Internal Reference ◽  
Traditional Design ◽  
State Reference ◽  
Interference Studies ◽  
Screen Printed

<p class="TRANSAffiliation"><span>This research focus on transforming the traditional design of reference electrode into all-solid-state reference electrode front-end using Ag/AgCl screen- printed electrodes. By replacing the internal reference solution of a traditional reference electrode by a solid photocurable membrane, an all-solid-state reference electrode can be achieved. The solid-state screen-printed reference electrode was designed using a photocurable acrylic film containing immobilized sodium tetrakis [3,5-bis(trifluoromethyl)phenyl] borate (NaTFPB) and trimethylocthylammonium chloride (TOMA-Cl). An optimum ratio of NaTFPB:TOMA-Cl = 1:1 produced a stable reference electrode. In the anions interference studies, all anions i.e. NO<sub>3</sub><sup>-</sup>, Cl<sup>-</sup>, Br<sup>-</sup> and SO<sub>4</sub><sup>2-</sup> does not give effect to the SPRE except perchlorate anions. The all-solid-state reference electrodes was applied to the detection of potassium ions  and ammonium ions. Validation of the all-screen-printed reference electrode was performed with reference electrode standard gel type. The validation results showed that all-solid-state screen-printed reference electrode demonstrated performance that was comparable to standard reference electrode. </span></p>

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