Three-dimensional NiCo2O4 nanosheets and nanoflowers electrodeposited with palladium nanoparticles on nickel foam for the hydrogen evolution reaction

By combining NiCo 2 O 4 with good hydrogen evolution reaction (HER) properties and palladium (Pd) nanoparticles with excellent conductivity, a highly efficient and stable catalyst is prepared for HER. The NiCo 2 O 4 nanosheets and NiCo 2 O 4 nanoflowers are produced on the nickel foam (NF) with a large specific surface area by a one-step hydrothermal method and the NiCo 2 O 4 nanoflowers are uniformly distributed in the NiCo 2 O 4 nanosheets to form a three-dimensional (3D) electrode. Compared to conventional NiCo 2 O 4 , the 3D NiCo 2 O 4 electrode provides more active sites (Ni and Co) for oxygen adsorption thus reducing the energy required to break H–O bonds to promote HER. When NiCo 2 O 4 /NF is combined with Pd nanoparticles (Pd/NiCo 2 O 4 /NF), the HER performance is improved greatly because of the synergistic effects rendered by the 3D structure of NiCo 2 O 4 and Pd nanoparticles. The overpotential of Pd/NiCo 2 O 4 /NF is 69 mV at a current density is 10 mA/cm 2 and it is stable for 10 h in alkaline environments. The materials design and properties provide useful information for future development of commercial hydrogen production .