Electrocatalysis developments for hydrogen evolution reaction in alkaline solutions – A Review

High capacity conversion anodes in Li-ion batteries: A review

Electrocatalytic activity of simple and modified Fe–P electrodeposits for hydrogen evolution from alkaline media

Electrochemically deposited thin films of amorphous Fe-P alloy. Part I. Chemical composition and phase structure characterization

Amorphous Fe–P alloys were electrodeposited under galvanostatic conditions at a current density of 10Adm–2 from sulfate–chlorine solutions containing β-alanine and glycine, as well as hypophosphoric acid. It was established that an increase in the deposition temperature from 50 to 60°C causes an increase in the deposition rate and a substantial rise in current efficiency and internal stress (IS). With pH increase from 2.0 to 3.0 the phosphorus content decreases, current efficiency almost doubles and there is a substantial drop in IS. It is assumed that a higher electrolyte acidity enhances hydrogen occlusion in the coating, which then desorbs from the deposit creating tensile IS. The same correlation between IS and current efficiency is observed when glycine concentration varies. A profile of residual IS is plotted illustrating the IS distribution throughout the deposit thickness. When the samples are magnetized in the coating plane, the shape of the hysteresis loop indicates perpendicular magnetic anisotropy. This is due to the columnar structure observed in scanning electron micrographs of the coating cross-sections. There is a linear dependence between IS and coercivity of amorphous Fe–P alloys deposited under different conditions.

Internal stress and magnetic properties of electrodeposited amorphous Fe-P alloys

Optimum conditions have been established for the electrodeposition of amorphous fe-P alloys from sulphate electrolytes, containing complex-forming additives (glycine and oxalic acid) and sodium hypophosphite. It was shown that the increase of pH, current density and glycine content in the plating solution leads to a decrease of the amount of phosphorus in the Fe-P alloy. The cathodic current yield decreases with the increase of glycine concentration in the electrolyte. Small amounts of Cu2+ and Mn2+ act as brighteners. Sodium hypophosphite exerts a depolarizing effect on the alloy formation process. This effect is more pronounced at low hypophosphite concentrations and low cathodic current densities (CCD). The measurement of the cathodic potential during the deposition of the investigated alloy provides no evidence for a concentration change of phosphorus in the electrodeposited layers. No qualitative alterations of the surface morphology of the amorphous coatings studied have been established as the composition of the alloy and the plating conditions are changed.

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Papers

Electrochemical preparation of amorphous Fe-P alloys