Hierarchical Ni/Ni(OH)2-NiCo2O4 Supported on Ni Foam as Efficient Bifunctional Electrocatalysts for Water Splitting

Developing efficient and cost-effective bifunctionalcatalytic electrodes is of great importance to water splitting. In thisstudy, hybrid Ni/Ni(OH)2-coated NiCo2O4nanorods were grownon Ni foam (NF) by a facile growth-conversion-epitaxyapproach. The epitaxial decoration of Ni/Ni(OH)2compositecould increase the intrinsic activity of NiCo2O4/NF and enhancethe charge-transfer rate. This self-standing hierarchical nanohybridwith unique surface chemistry and interface engineering exhibits anexcellent electrocatalytic performance. The optimized Ni/Ni-(OH)2-NiCo2O4/NF only requires overpotentials of 53 and 235mV to reach a current density of 10 mA cm-2for HER and OER,respectively. The electrolyzer achieved 10 mA cm-2at a low cellvoltage of 1.51 V for water splitting. This work offers a newperspective for rationally designing electrocatalytic materials by surface decoration.