Prussian Blue Analogue-Assisted Formation of Iron-Nickel Selenide Porous Nanosheets for Enhanced Oxygen Evolution

The development of active and stable electrocatalysts made from earth-abundant elements to accelerate the oxygen evolution reaction (OER) kinetics is of great significance for improving the efficiency of overall water splitting. Herein, a Prussian blue analogue (PBA)-assisted strategy to synthesize FeSe-NiSe nanosheets is reported. With this approach, porous FeSe-NiSe nanosheets supported on conductive Ni foam (NF) are fabricated via controlled chemical etching of Ni(OH)2/NF with Fe(CN)63- and subsequent selenylation treatment. The as-derived FeSe-NiSe/NF electrode with unique interpenetrated porous three-dimensional (3D) network architecture successfully combines the desired merits including high conductivity and a large specific surface area. As a result, it exhibits enhanced electrocatalytic OER performance in alkaline media, which requires overpotentials of only 234 and 268 mV to deliver current densities of 10 and 100 mA cm-2, respectively, outclassing its counterpart NiSe/NF. Furthermore, the catalyst possesses a very low Tafel slope (22 mV dec-1) and excellent durability.