scholarly journals Electrodeposition and characterization of Fe–Mo alloys as cathodes for hydrogen evolution in the process of chlorate production

2005 ◽  
Vol 70 (6) ◽  
pp. 879-889 ◽  
Author(s):  
Branimir Grgur ◽  
Nedeljko Krstajic ◽  
Nevenka Elezovic ◽  
Vladimir Jovic
Keyword(s):  
Mild Steel ◽  
Hydrogen Evolution ◽  
Current Density ◽  
Alloy Composition ◽  
Bath Composition ◽  
Alloy Electrodeposition ◽  
Ac Current ◽  
Deposition Conditions ◽  
Chlorate Production

Fe?Mo alloys were electrodeposited from a pyrophosphate bath using a single diode rectified AC current. Their composition and morphology were investigated by SEM, optical microscopy and EDS, in order to determine the influence of the deposition conditions on the morphology and composition of these alloys. It was shown that the electrodeposition parameters, such as chemical bath composition and current density, influenced both the composition of the Fe?Mo alloys and the current efficiency for their deposition, while the micro and macro-morphology did not change significantly with changing conditions of alloy electrodeposition. It was found that the electrodeposited Fe?Mo alloys possessed a 0.15 V to 0.30 V lower overvoltage than mild steel for hydrogen evolution in an electrolyte commonly used in commercial chlorate production, depending on the alloy composition, i.e., the conditions of alloy electrodeposition.

Study of Optimum Conditions for Zinc Plating on Mild Steel

2010 ◽  
Vol 2 ◽  
pp. 31-39 ◽  
Author(s):  
Muhammed Olawale Hakeem Amuda ◽  
W. Subair ◽  
O.W. Obitayo
Keyword(s):  
Mild Steel ◽  
Process Parameters ◽  
Current Density ◽  
Optimum Conditions ◽  
Plating Bath ◽  
Zinc Plating ◽  
Electroplating Process ◽  
Deposition Conditions

The effect of some process parameters on the weight of zinc deposited on mild steel in a typical electroplating process is reported. The study indicates that the weight of zinc deposited on mild steel during the process is affected by plating temperature, current density, plating bath pH and plating time. The study established that optimum deposition of zinc is achieved at plating temperature of 320C, plating bath pH of 4.4, current density 40mA/cm2 and plating time of 30 minutes. 8.7mg of zinc was deposited at optimum deposition conditions. The profile of the zinc deposited decreases after optimum deposition is attained.

scholarly journals MORPHOLOGY AND PROPERTIES OF ELECTRODEPOSITED ZN-NI ALLOY COATINGS ON MILD STEEL

1970 ◽  
Vol 40 (1) ◽  
pp. 9-14 ◽  
Author(s):  
M J Rahman ◽  
S R Sen ◽  
M Moniruzzaman ◽  
K M Shorowordi
Keyword(s):  
Corrosion Resistance ◽  
Mild Steel ◽  
Current Density ◽  
Perfect Crystal ◽  
Corrosion Property ◽  
Alloy Electrodeposition ◽  
Sulfate Bath ◽  
Ni Alloy ◽  
Electrochemically Deposited ◽  
A Current

Zinc-nickel alloys electrochemically deposited on mild steel under various deposition conditions were investigated. The effect of plating variables (bath composition, pH, current density) on the coating composition, morphology, corrosion property and microhardness were investigated. Modified morphology with perfect crystal growth, uniform arrangement of crystals, refinement in crystal size and hence bright deposit was obtained from sulfate Bath-3 containing 30 g/l H3BO3 at a current density of 75 mA/cm2. Corrosion resistance as well as microhardness of Zn-Ni alloy coatings increased with the increase of %Ni in the deposit for all the sulphate baths studied. Optimum conditions for good deposition are also discussed. Keywords: Zn-Ni alloy, electrodeposition, morphology, corrosion resistance.   doi: 10.3329/jme.v40i1.3468 Journal of Mechanical Engineering, Vol. ME40, No. 1, June 2009 9-14

scholarly journals Fe-Mo alloy coatings as cathodes in chlorate production process

2016 ◽  
Vol 70 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Ljiljana Gajic-Krstajic ◽  
Nevenka Elezovic ◽  
Borka Jovic ◽  
Gian Martelli ◽  
Vladimir Jovic ◽  
...  
Keyword(s):  
Mild Steel ◽  
Current Efficiency ◽  
Hydrogen Evolution ◽  
Partial Replacement ◽  
Complete Suppression ◽  
Cathode Reaction ◽  
Mo Catalyst ◽  
Potentiometric Titration Method ◽  
Steel Cathode ◽  
Chlorate Production

The aim of this study was to gain a better understanding of the feasibility of partial replacement of dichromate, Cr(VI), with phosphate buffer, focusing on the cathode reaction selectivity for hydrogen evolution on mild steel and Fe-Mo cathodes in undivided cell for chlorate production. To evaluate the ability of phosphate and Cr(VI) additions to hinder hypochlorite and chlorate reduction, overall current efficiency (CE) measurements in laboratory cell for chlorate production on stationary electrodes were performed. The concentration of hypochlorite was determined by a conventional potentiometric titration method using 0.01 mol dm-3 As2O3 solution as a titrant. The chlorate concentration was determined by excess of 1.0 mol dm-3 As2O3 solution and excess of arsenic oxide was titrated with 0.1 mol dm-3 KBrO3 solution in a strong acidic solution. Cathodic hypochlorite and chlorate reduction were suppressed efficiently by addition of 3 g dm-3 dichromate at both cathodes, except that Fe-Mo cathode exhibited higher catalytic activity for hydrogen evolution reaction (HER). The overvoltage for the HER was around 0.17 V lower on Fe-Mo cathode than on mild steel at the current density of 3 kA m-2. It was found that a dichromate content as low as 0.1 g dm-3 is sufficient for complete suppression of cathodic hypochlorite and chlorate reduction onto Fe-Mo catalyst in phosphate buffering system (3 g dm-3 Na2HPO4 + NaH2PO4). The overall current efficiency was practically the same as in the case of the presence of 3 g dm-3 dichromate buffer (98 %). However, for the mild steel cathode, the overall current efficiency for the chlorate production was somewhat lower in the above mentioned mixed phosphate + dichromate buffering system (95%) than in the pure dichromate buffering solution (97.5%).

A highly stable CoMo2S4/Ni3S2 heterojunction electrocatalyst for efficient hydrogen evolution

2021 ◽  
Author(s):  
Minmin Wang ◽  
Mengke Zhang ◽  
Wenwu Song ◽  
Weiting Zhong ◽  
Xunyue Wang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Current Density ◽  
A Current

A CoMo2S4/Ni3S2 heterojunction is prepared with an overpotential of only 51 mV to drive a current density of 10 mA cm−2 in 1 M KOH solution and ∼100% of the potential remains in the ∼50 h chronopotentiometric curve at 10 mA cm−2.

scholarly journals Lamellar Polypyrene Based on Attapulgite–Sulfur Composite for Lithium–Sulfur Battery

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 483
Author(s):  
Jing Wang ◽  
Riwei Xu ◽  
Chengzhong Wang ◽  
Jinping Xiong
Keyword(s):  
Cathode Material ◽  
Current Density ◽  
High Current Density ◽  
Specific Capacity ◽  
Lithium Sulfur Batteries ◽  
Rate Test ◽  
Sulfur Battery ◽  
Lower Capacity ◽  
Lithium Sulfur

We report on the preparation and characterization of a novel lamellar polypyrrole using an attapulgite–sulfur composite as a hard template. Pretreated attapulgite was utilized as the carrier of elemental sulfur and the attapulgite–sulfur–polypyrrole (AT @400 °C–S–PPy) composite with 50 wt.% sulfur was obtained. The structure and morphology of the composite were characterized with infrared spectroscopy (IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). An AT @400 °C–S–PPy composite was further utilized as the cathode material for lithium–sulfur batteries. The first discharge specific capacity of this kind of battery reached 1175 mAh/g at a 0.1 C current rate and remained at 518 mAh/g after 100 cycles with capacity retention close to 44%. In the rate test, compared with the polypyrrole–sulfur (PPy–S) cathode material, the AT @400 °C–S–PPy cathode material showed lower capacity at a high current density, but it showed higher capacity when the current came back to a low current density, which was attributed to the “recycling” of pores and channels of attapulgite. Therefore, the lamellar composite with special pore structure has great value in improving the performance of lithium–sulfur batteries.

scholarly journals Microwave-Assisted vs. Conventional Hydrothermal Synthesis of MoS2 Nanosheets: Application towards Hydrogen Evolution Reaction

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1040 ◽  
Author(s):  
Getachew Solomon ◽  
Raffaello Mazzaro ◽  
Vittorio Morandi ◽  
Isabella Concina ◽  
Alberto Vomiero
Keyword(s):  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Crystal Morphology ◽  
Synthesis Method ◽  
Synthesis Methods ◽  
Mos2 Nanosheets ◽  
Microwave Assisted

Molybdenum sulfide (MoS2) has emerged as a promising catalyst for hydrogen evolution applications. The synthesis method mainly employed is a conventional hydrothermal method. This method requires a longer time compared to other methods such as microwave synthesis methods. There is a lack of comparison of the two synthesis methods in terms of crystal morphology and its electrochemical activities. In this work, MoS2 nanosheets are synthesized using both hydrothermal (HT-MoS2) and advanced microwave methods (MW-MoS2), their crystal morphology, and catalytical efficiency towards hydrogen evolution reaction (HER) were compared. MoS2 nanosheet is obtained using microwave-assisted synthesis in a very short time (30 min) compared to the 24 h hydrothermal synthesis method. Both methods produce thin and aggregated nanosheets. However, the nanosheets synthesized by the microwave method have a less crumpled structure and smoother edges compared to the hydrothermal method. The as-prepared nanosheets are tested and used as a catalyst for hydrogen evolution results in nearly similar electrocatalytic performance. Experimental results showed that: HT-MoS2 displays a current density of 10 mA/cm2 at overpotential (−280 mV) compared to MW-MoS2 which requires −320 mV to produce a similar current density, suggesting that the HT-MoS2 more active towards hydrogen evolutions reaction.

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