Electrodeposition of nano-structured nickel-21% tungsten alloy and evaluation of oxygen reduction reaction in a 1% sodium hydroxide solution

The nano-structured nickel-21 at.% tungsten alloys were electrodeposited onto the copper substrates from unstirred sulfate-citrate-chloride-bromide-sodium tungstate electrolyte at 60 deg. C. The maximum particle sizes of the deposits, as estimated from the atomic force microscopy (AFM), and scanning electron microscopy (SEM), respectively were 125, 75, and 100 nm. The Tafel plot for oxygen reduction reaction in oxygenated unstirred 1% sodium hydroxide solution showed a Tafel slope of 130 mV/decade. There were minor variations in the limiting current density with a change in the particle size