Prussian blue analogue assisted construction of hierarchical CoS2@(Fe,Ni)S2 heterostructures for efficient electrocatalytic oxygen evolution reaction

The large-scale application of water electrolysis technology is limited by the slow kinetics of the oxygen evolution reaction (OER) that cause vast energy loss. Rational design and construction of hierarchical heterostructures are helpful for developing efficient OER electrocatalysts due to their interesting morphological features and electrochemical properties. Herein, we prepared hierarchical CoS 2 @(Fe,Ni)S 2 heterostructures on carbon fiber paper (CoS 2 @(Fe,Ni)S 2 /CFP) with particle-on-wire morphology using prussian blue analogue as template and precursor. The unique hierarchical heterostructure maximizes accessible active sites and the synergistic effect between different components significantly improves electrocatalytic activity. Impressively, CoS 2 @(Fe,Ni)S 2 /CFP electrocatalyst requires a small overpotential of 237 mV to achieve a current density of 20 mA cm −2 with a low Tafel slope of 54 mV dec −1 and the corresponding voltage has no obvious change after 60 h stability test under a constant current density of 50 mA cm −2 in 1 M KOH solution. This work provides a new idea for the design of efficient and stable non-noble metal-based OER electrocatalysts.