Effect of TiO2 on electrocatalytic behavior of Ni-Mo alloy coating for hydrogen energy
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Date
2018
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Publisher
KeAi Communications Co.
Abstract
Ni-Mo-TiO<inf>2</inf> composite coating has been developed through electrodeposition method by depositing titanium dioxide (TiO<inf>2</inf>) nanoparticles parallel to the process of Ni-Mo alloy coating. The experimental results explaining the increased electrocatalytic activity of Ni-Mo alloy coating on incorporation of TiO<inf>2</inf> nanoparticles into its alloy matrix is reported here. The effect of addition of TiO<inf>2</inf> on composition, morphology and phase structure of TiO<inf>2</inf> – composite coating is studied with special emphasis on its electrocatalytic activity for hydrogen evolution reaction (HER) in 1.0 M KOH solution. The electrocatalytic activity of alloy coatings were validated using cyclic voltammetry (CV) and chronopotentiometry (CP) techniques. Under optimal condition, TiO<inf>2</inf> – composite alloy coating represented as (Ni-Mo-TiO<inf>2</inf>)<inf>2.0 A dm?2</inf> is found to exhibit the highest electrocatalytic activity for HER compared to its binary alloy counterpart. The increased electrocatalytic activity of (Ni-Mo-TiO<inf>2</inf>)<inf>2.0 A dm?2</inf> composite coating was attributed to the increased Mo content, porosity and roughness of coating, affected due to addition of TiO<inf>2</inf> nanoparticles, supported by SEM, EDX, XRD and AFM study. The increased electrocatalytic activity of (Ni-Mo-TiO<inf>2</inf>)<inf>2.0 A dm?2</inf> coating was found due to decreased R<inf>ct</inf> and increased C<inf>dl</inf> values, demonstrated by EIS study. Better electrocatalytic activity of (Ni-Mo-TiO<inf>2</inf>)<inf>2.0 A dm?2</inf> coating, compared to (Ni-Mo)<inf>2.0 A dm?2</inf> coating has been explained through mechanism. Experimental study revealed that (Ni-Mo-TiO<inf>2</inf>)<inf>2.0 A dm?2</inf> composite coating follows Volmer-Heyrovsky mechanism, compared to Tafel mechanism in case of (Ni-Mo-TiO<inf>2</inf>)<inf>2.0 A dm?2</inf> coating, assessed on the basis of Tafel slopes. © 2018
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Keywords
Composite coatings, Cyclic voltammetry, Metallic matrix composites, Molybdenum alloys, Nanoparticles, Nickel alloys, Potassium hydroxide, Titanium alloys, Titanium dioxide, Alloy coatings, Alloy matrix, Composites coating, Electrocatalytic activity, Electrocatalytic behavior, Electrodeposition methods, Hydrogen Energy, Hydrogen evolution reactions, Ni-mo alloy coating, Ni-mo-TiO2 composite coating, Binary alloys
Citation
Materials Science for Energy Technologies, 2018, 1, 2, pp. 97-105