Study of the hydrogen evolution reaction on Fe–Mo–P coatings as cathodes for chlorate production

Binary Fe–Mo and ternary Fe–Mo–P coatings have been electrochemically deposited from citrate-based electrolyte on mild steel (MS) substrate. Galvanostatic electrodepositions have been conducted for 6 h at 20 mA cm−2 and 30 °C. The electrocatalytic activity of these alloys towards hydrogen evolution reaction (HER) was assessed using steady-state polarization and electrochemical impedance spectroscopy (EIS) techniques. Electrochemical tests were carried out in sodium chloride solutions. All electrodeposited alloys yielded the amorphous structure, revealed by X-ray diffraction patterns. At a current density of 250 mA cm−2, the Fe54Mo30P16 electrode reduced the HER overpotential by 30% in comparison with mild steel. This electrocatalyst also showed an enhancement of 16.5% for the HER overpotential as compared to the binary alloy of Fe53Mo47. The steady-state polarization and EIS results revealed that both the surface roughness and intrinsic activity could be the origin of the promising behaviour of Fe–Mo–P electrocatalyst towards HER. The ternary alloy of Fe–Mo–P could be a considerable candidate in enhancing the HER for alkaline media.