The effect of the hypophosphite ion oxidation on the Ni surface electrode—an XPS study

The effect of the hypophosphite electrooxidation on the Ni surface state was analysed by XPS on electrodes previously submitted to constant-potential polarization in an alkaline solution containing the hypophosphite ion. It was found that Ni surface exhibits the same electronic states than in a hypophosphite-free solution. The XPS spectra of P 2p and P 2s revealed the formation of alloyed phosphorus on the Ni surface. Its dependence on the electrode potential allows concluding that hypophosphite ion participates in competitive surface reactions in the same potential range. The overall results are discussed in the light of the mechanisms proposed in the literature for the phosphorus incorporation process during Ni–P alloy electrodeposition.