Disordered and oxygen vacancy-rich NiFe hydroxides/oxides in situ grown on amorphous ribbons for boosted alkaline water oxidation

Abstract The amorphous catalysts can be electrochemically activated to expose active sites during the short-range order structure, greatly increasing the number of active sites and thus significantly improving the water oxidation activity. Herein, we developed disordered sandwich-like multi-layer structure with abundant oxygen vacancies as a highly excellent electrocatalyst for the oxygen evolution reaction (OER), which was derived from amorphous Ni40Fe40B20 ribbons precursors through in situ hydroxylation and electro-oxidation in alkaline solution. The as-fabricated product shows the low overpotential of 249 mV and 338 mV at a current of 10 mA·cm−2 and 250 mA·cm−2 with a Tafel slope of 43 mV·dec−1, respectively. This excellent catalytic performance is attributed to the synergistic effect resulted from the hybrid composition of disordered α-Ni(OH)2 and γ-FeOOH, excellent electron/mass transfer due to the presence of abundant oxygen vacancies and expandable actual surface area. Moreover, the catalysts after structural reconstruction still maintain good flexibility, which is good for industrial applications. This work may provide insight into the combination of disordered structure and oxygen vacancies through in situ grown on amorphous alloys and make them as promising industrial OER electrocatalysts.