Proposed in 1968, solvated Ni ions at the catalytic surface ionized water and forms a hydroxide coordinated Ni ion. The hydrolyzed Ni2+ ion catalyzes the production of Ni, P, and H2. Water is ionized at the Ni surface [14], and Ni2+ ions coordinate with hydroxide ions [15]. The coordinated Ni2+ is reduced [16] and NiOH+ab is adsorbed on the substrate surface. At the surface H2PO2- reduces NiOH+ab to elemental Ni0 [17]. The released elemental H recombine to form hydrogen gas and [18] and elemental Ni catalyses the production of the P [19]. The deposited Ni acts as a catatalyst due continued reduction by H2PO2- [17]. Cavallotti and Salvago also proposed that the NiOH+ab [20] and water combination oxidises to Ni2+ and elemental H. The NiOH+ab participates in a competing reaction [21a] (refers to reaction [17] )and [21b] to for elemental Ni and hydrolized Ni respectively. Finally H2PO2- is oxidized [22] and elemental H [21a/21b] recombine to form and H2 evolves for both reactions. The overall reactions is shown in equation [23].
