engleski

Characterization of Ni, NiMo, NiW and NiFe electroactive coatings as electrocatalysts for hydrogen evolution in an acidic medium

The paper reports a study on the influence of alloying nickel by left-hand side transition metals (Fe, Mo, W) on the electrocatalytic activity in hydrogen evolution in an acidic environment. A number of experimental techniques were used in research (dc and ac electrochemical techniques, XRD, SEM, EDS, and ICP). The results clearly demonstrate that alloying nickel with Fe, Mo or W results in an increased electrocatalytic activity in hydrogen evolution when compared to pure nickel. Two effects were found to be responsible for the observed behavior ; an increase in surface roughness and intrinsic activity of the material. Ni_7.3Mo was found to yield the highest overall electrocatalytic activity among the investigated materials mainly due the highest surface roughness, while Ni_3.4W was found to yield the highest intrinsic electrocatalytic activity, which is explained on the basis of the modification of electron density in d-orbitals upon alloying nickel with tungsten. It was also noticed that an increase in crystallinity can contribute to an increased electrocatalytic activity in hydrogen evolution.

Hydrogen ; Water electrolysis ; Acidic medium ; Electrocatalytic coatings ; Nickel based alloys.

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