FeCo2S4/Ni foam: A Bimetallic Sulfide Electrocatalyst with Efficient and Robust Behavior

The development of effective, feasible, stable, and inexpensive electrocatalysts has been a great challenge in the field of overall water splitting (WS). Herein, a bifunctional electrocatalyst (BF ECS), FeCo2S4 nanowire (FCS NWs/Ni)/nickel (Ni) foam, with superior HER/OER activity and stability was designed and fabricated using a hydrothermal method. In addition, this efficient method can be used for the synthesis of other bimetallic MCo2S4 sulfides (M = Cu, Zn, Mn, etc.). Electrochemical experiments showed the as-synthesized FCS NWs/Ni exhibited overpotentials of 350.5, 203.7, 115.97, and 62.6 mV (0.05, 0.1, 0.2, and 1 M KOH) at the current density of −10 mA cm−2 for HER, including small overpotentials of 1.51, 1.36, 1.24, and 1.11 V (10 mA cm−2) in a 0.05, 0.1, 0.2, and 1 M KOH solution for OER. The FCS NWs/Ni has a splendid electrocatalytic performance which is related to the synergistic effect of cobalt, iron, and sulfur. Specifically, it has excellent electrical conductivity, a higher specific capacity, and a rich redox state of iron, cobalt, and sulfur elements. The results demonstrate a promising method for the design and fabrication of metal BF ECS for overall water splitting.