In situ surface Raman study of the phosphorus incorporation mechanism during electrodeposition of Ni–P alloys

Codeposition of phosphorus with nickel on an Ni–Ag alloy electrode has been investigated by means of in situ surface enhanced Raman spectroscopy (SERS) to obtain information about the phosphorus incorporation mechanism during electrodeposition of Ni–P alloys. The experimental results showed that in the solution without NiSO4, hypophosphite was reduced only to a Ni–phosphine compound, while in the case where NiSO4 coexisted in the solution, the Ni–phosphine compound, as an intermediate, was oxidized by Ni2+ to elemental phosphorus in alloys with nickel acting as the catalyst.