scholarly journals Investigations on the Redox Characteristics and Hydrogen Evolution Efficiencies of Pd and Mo Deposited Pd Electrodes in Alkaline Electrolyte

1970 ◽  
Vol 43 (1) ◽  
pp. 103-116 ◽  
Author(s):  
M Ashraful Islam Molla ◽  
Mithun Sarker ◽  
AKM Fazle Kibria
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Adsorption ◽  
Stable Condition ◽  
Alkaline Electrolyte ◽  
Potential Range ◽  
Cyclic Voltammograms ◽  
Absorption Region ◽  
Potential Value ◽  
Density Values ◽  
Hydrogen Evolution Reactions

Redox behaviors and hydrogen evolution efficiencies of Pd and Mo deposited Pd electrodes have been investigated in 30wt.% KOH electrolyte by cyclic voltammetry. Cyclic voltammograms of Pd electrode in between the potential range - 1.05 V to + 0.75 V showed two couples of redox peaks for the transformations of Pd(0) ←→ Pd(OH)2 and Pd(OH)2 ←→ PdOOH, an anodic peak for the desorption of diffusional hydrogen (dH) and hydrogen and oxygen evolutions at the terminal potential regions. Hydrogen evolution efficiency found decreased with time and then reached to a stable condition after 35 minutes. In presence of deposited Mo, the electrode stable condition appeared after 10 minutes only. Pd found predominates over deposited Mo. Both the Pd(0) ←Pd(OH)2 and Mo(0) ← Mo(OH)2 transformations appeared at the same potential value. Mo stopped the movement of hydrogen adsorption and absorption region of Pd electrode towards negative potential direction. It increased the hydrogen evolution efficiency of Pd electrode remarkably. At the potentials - 1.1 V, - 1.2 V, - 1.25 V and - 1.3 V, currents for Pd + Mo system found 1.44, 1.25, 1.20, 1.23 times higher than those of Pd electrode. Mo also showed hydrogen migratory role to the fraction of Pd surface covered by it. Hydrogen evolution reactions (HER) over Pd and Pd + Mo surfaces seemed followed similar mechanisms. Tafel plots for the HER for both the systems showed two Tafel regions. Exchange current density values (io) for the low and high overpotential regions of Pd + Mo system showed 2.85 times and 1.29 times higher values than those of Pd electrode. Key words: Pd, Pd-Mo, Hydrogen evolution efficiency, Hydrogen evolution reactions (HER) DOI: 10.3329.bjsir.v43i1.861 Bangladesh J. Sci. Ind. Res. 43(1), 103-116, 2008

scholarly journals Oxidation-Reduction Behaviours, Electrolysis Characteristics and Efficiency of Pd-50at.%Ni Electrode in Alkaline Electrolyte

1970 ◽  
Vol 33 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Md Ashraful Islam Molla ◽  
Mithun Sarker ◽  
Rafiqul Islam ◽  
AKM Fazle Kibria
Keyword(s):  
Reaction Kinetics ◽  
Hydrogen Evolution ◽  
Surface Reaction ◽  
Alkaline Electrolyte ◽  
Potential Range ◽  
Cyclic Voltammogram ◽  
Oxidation Reduction ◽  
Density Values ◽  
Surface Reaction Kinetics ◽  
Academy Of Sciences

Convinced on the necessity of finding effective electrodes for electrolyser- the oxidation-reduction behaviors, surface reaction kinetics, stability, electrolysis characteristics and efficiency of a Pd-50at.%Ni electrode have been investigated in 30wt.%KOH electrolyte at room temperature using cyclic voltammetry. Cyclic voltammogram of the electrode showed three couples of oxidation-reduction peaks in between the potential range - 1.0 to + 0.65 V. These peaks were found to be originated from the transformation of zero valent metal to their higher oxides in three consecutive steps and vice versa. The peak potentials, potential differences of the couples and the peak currents were found remarkably different from those of Pd and Ni electrodes. The surface reaction kinetics at Pd-Ni electrode followed the surface reaction trends similar to those of Pd and Ni electrodes. The apparent stability of the electrode was found good. The electrode showed 1.6 and 6.8 times higher oxygen evolution efficiencies than the Ni and Pd electrodes. Addition of Ni with Pd caused hydrogen evolution potentials to move to the negative direction. Tafel plot for the hydrogen evolution reactions (HER) showed two well-defined Tafel regions. Kinetic parameters, i.e., Tafel slope and exchange current density values for the low and high overpotential regions were found 127 mV/dec and 273 mV/dec, and 1.72 x 10-2 mA/cm2 and 1.52 mA/cm2, respectively. Observed slopes indicated its better efficiency over the Pd electrode. Journal of Bangladesh Academy of Sciences, Vol. 33, No. 1, 1-13, 2009 doi: 10.3329/jbas.v33i1.2945

scholarly journals Electrochemistry of active chromium, part III: Effects of temperature

2003 ◽  
Vol 68 (11) ◽  
pp. 871-882 ◽  
Author(s):  
Jovan Popic ◽  
Dragutin Drazic
Keyword(s):  
Corrosion Rate ◽  
Hydrogen Evolution ◽  
Anodic Dissolution ◽  
Electrochemical Corrosion ◽  
Potential Range ◽  
Temperature Dependences ◽  
Hydrogen Evolution Reactions ◽  
Effects Of Temperature ◽  
Best Fit ◽  
Anomalous Dissolution

It was shown that the temperature in the range 20 ? 65 ?C has considerable effects on the electrochemical anodic dissolution of chromium in the active potential range as well as on the electrochemical hydrogen evolution reactions on bare and oxide covered chromium surfaces. Also, the chemical dissolution of chromium is strongly affected. The apparent energy of activation for anodic dissolution is 63.1 kJ mol-1, for hydrogen evolution on a bare Cr surface 19.5 kJ mol-1, for the same reaction on an oxide covered surface 44.0 kJ mol-1 and for the chemical ("anomalous") dissolution 66.9 kJ mol-1. The temperature dependences of the total corrosion rate, and the electrochemical corrosion rate alone, are presented in polynomial forms with the appropriate constants obtained by the best fit of the experimental data. For the hydrogen evolution reaction on both bare and oxide covered chromium, the Volmer-Heyrovsky reaction mechanism with the second step as rate determining was proposed.

Design of ultralong single-crystal nanowire-based bifunctional electrodes for efficient oxygen and hydrogen evolution in a mild alkaline electrolyte

2017 ◽  
Vol 5 (22) ◽  
pp. 10895-10901 ◽  
Author(s):  
Ge Li ◽  
Xiaolei Wang ◽  
Min Ho Seo ◽  
Sahar Hemmati ◽  
Aiping Yu ◽  
...  
Keyword(s):  
Single Crystal ◽  
Hydrogen Evolution ◽  
Zno Nanowires ◽  
Alkaline Electrolyte ◽  
Hydrogen Evolution Reactions ◽  
Doped Zno ◽  
Co Doped

A 3D flexible bifunctional electrode based on ultralong single-crystal Co-doped ZnO nanowires has been successfully designed and developed for efficient oxygen and hydrogen evolution reactions.

Enhanced electrochemical oxygen and hydrogen evolution reactions using an NU-1000@NiMn-LDHS composite electrode in alkaline electrolyte

2020 ◽  
Vol 56 (49) ◽  
pp. 6652-6655 ◽  
Author(s):  
Soheila Sanati ◽  
Reza Abazari ◽  
Ali Morsali
Keyword(s):  
Hydrogen Evolution ◽  
Current Density ◽  
Composite Electrode ◽  
Alkaline Electrolyte ◽  
Electrocatalytic Performance ◽  
Hydrogen Evolution Reactions ◽  
A Current ◽  
Electrochemical Oxygen

A well-designed NU-1000@NiMn-LDHS (NU@LDHS) composite can offer efficient electrocatalytic performance with ultralow HER and OER overpotentials of 93 and 129 mV, respectively, at a current density of 10 mA cm−2 in 2 M KOH.

scholarly journals Effect of Ethylene Diamine Tetra Acetic Acid (EDTA) on the Surface Reaction Behavior and the Hydrogen Evolution Efficiency of Ni-30at.%Cu Electrode in Alkaline Medium

1970 ◽  
Vol 43 (2) ◽  
pp. 145-158
Author(s):  
AKM Fazle Kibria
Keyword(s):  
Acetic Acid ◽  
Hydrogen Evolution ◽  
Surface Reaction ◽  
Ethylene Diamine ◽  
Potential Range ◽  
Cyclic Voltammogram ◽  
Oxidation Reduction ◽  
Hydrogen Evolution Reactions ◽  
Kinetics Of ◽  
Voltammetric Technique

The surface reaction characteristics, hydrogen evolution efficiency and hydrogen evolution reaction kinetics of Ni-30at.%Cu electrode have been investigated in 30wt.%KOH electrolyte in presence and absence of ethylene diamine tetra acetic acid (EDTA) at room temperature by cyclic voltammetric technique. Cyclic voltammogram of the electrode showed three couples of oxidation-reduction peaks in between the potential range - 1.1 to + 0.4 V. The peak couples were originated from the electrochemical transformations of Ni(0) ←→ Ni(OH)2, Cu(0) ←→ Cu(I) and Cu(I) ←→ Cu(OH)2. An interference of the adsorped hydrogen over Cu(0) surface on the transformation of Ni(OH) 2 → Ni(0) was found. It was realized that added EDTA forms Cu-EDTA complex over the electrode surface. With increasing the amount of EDTA, the thickness of Cu(OH) 2 layer gradually decreased. Addition of 0.04g, 0.08g and 0.12g EDTAincreased the hydrogen evolution efficiency of the electrode more than 6%, 12% and 17%. Tafel plots for both the systems showed two well-defined Tafel regions. 0.12g EDTA increased the exchange current density (i0) values 1.3 times for both the Tafel regions. The observed i0 value for the high overpotential (η) region is 1.8 and 2.9 times higher than those of Ni and Cu electrodes. The Tafel slope (b) values for both the low and high η regions are smaller than those observed for without EDTA system and also for the Ni electrode. From the achieved information, it can be concluded that addition of EDTA remarkably increased the hydrogen evolution efficiency of the Ni-30at.%Cu electrode. It seems that hydrogen evolution reactions (HER) followed like mechanisms in absence and presence of EDTA. Key words: Ni-30at.%Cu electrode, EDTA, Electrochemical transformation, Surface reactions, Hydrogen evolution, Hydrogen evolution reactions (HER)DOI: 10.3329/bjsir.v43i2.955 Bangladesh J. Sci. Ind. Res. 43(2), 145-158, 2008

Corrigendum to “rGO supported NiWO4 nanocomposites for hydrogen evolution reactions” [Mater. Lett. 240 (2019) 51–54]

2021 ◽  
Vol 285 ◽  
pp. 129209
Author(s):  
Jahangeer Ahmed ◽  
Tansir Ahamad ◽  
Mohd Ubaidullah ◽  
Abdullah M. Al-Enizi ◽  
Ameen N. Alhabarah ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reactions
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