Rational design of amorphous NiFe-LDH/Co3O4-P heterostructure bifunctional electrocatalysts for overall water splitting

Rational design of high-performance and low-cost bifunctional electrocatalysts is critical for the overall effi-ciency of water splitting. In this paper, P-doped urchin-like Co3O4 (Co3O4-P) was fabricated on Ni foam by a hydrothermal synthesis and subsequently annealed in phosphorus source, and then amorphous NiFe hydroxide nanosheets (NiFe-LDH) was grown on the surface of Co3O4-P by an in-situ electrodeposition method to form the heterostructure. The composites show a dendritic structure, low interface resistance, and large active catalytic area, and the introduction of oxygen evolution reaction (OER) active components enables the substrate to obtain excellent performance. The heterostructure structure shows excellent OER and HER performance in alkaline media, the overpotential is only 269.9 mV and 168.5 mV for OER and HER when the current density reaches 50 mA cm- 2, respectively. The electrolyzer assembled by NiFe-LDH25/Co3O4-P as anode and cathode need only 1.51 V to reach 50 mA cm-2 for overall water splitting, it also shows excellent stability.