Improved Alkaline Hydrogen Evolution Performance of Dealloying Fe75−xCoxSi12.5B12.5 Electrocatalyst

The electrocatalytic performance of a Fe₆₅Co₁₀Si_12.5B_12.5 Fe-based compounds toward alkaline hydrogen evolution reaction (HER) is enhanced by dealloying. The dealloying process produced a large number of nanosheets on the surface of NS-Fe₆₅Co₁₀Si_12.5B_12.5, which greatly increased the specific surface area of the electrode. When the dealloying time is 3 h, the overpotential of NS-Fe₆₅Co₁₀Si_12.5B_12.5 is only 175.1 mV at 1.0 M KOH and 10 mA cm^-2, while under the same conditions, the overpotential of Fe₆₅Co₁₀Si_12.5B_12.5 is 215 mV, which is reduced. In addition, dealloying treated electrodes also show better HER performance than un-dealloying treated electrodes. With the increase in Co doping amount, the overpotential of the hydrogen evolution reaction decreases, and the hydrogen evolution activity is the best when the addition amount of Co is 10%. This work not only provides a basic understanding of the relationship between surface activity and the dealloying of HER catalysts, but also paves a new way for doping transition metal elements in Fe-based electrocatalysts working in alkaline media.