engleski

Nanostructured Nickel Films: Electrocrystallization on Carbon Microelectrodes and Electrocatalytic Properties for the HER

The very initial nucleation stage of the electrocrystallization of nanostructured nickel particles has been studied on an assembly of carbon fibres, consisting of 36, 000 microdiscs randomly distributed inside the matrix of a non-conducting polymer. Microdiscs were so far apart that the crystals could not interact in any way. It was shown that electrodes with very small electroactive areas simplify the study of the nucleation and growth mechanism. Within an appropriate potential range the initial deposition kinetic corresponds to a three-dimensional progressive nucleation mechanism and diffusion controlled stable cluster growth. Relevant kinetic parameters ; the nucleation rate and the number of atoms in the critical nucleus including the diffusion coefficient were determined from the electrochemical in situ measurements. The deposit morphology was examined by ex situ methods. The electrocatalytic performance of Ni nanoparticles supported on carbon microelectrodes with respect to the hydrogen evolution reaction (HER) has been evaluated on the basis of dc-electrochemical and ac-impedance spectroscopy measurements in a 1M NaOH solution. Obtained results indicate the excellent electrocatalytic activity of the nanostructured Ni deposit towards H_2 evolution in comparison to the bulk polycrystalline Ni.

nickel nanoparticles ; carbon fibre microelectrode ; electrocrystallisation (nucleation) ; electrocatalysis ; hydrogen evolution reaction

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