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.