Hierarchical Design of NiOOH@Amorphous Ni-P Bilayer on a 3D Mesh Substrate for High-Efficiency Oxygen Evolution Reaction.

Recently, 3d metal phosphide and metal-phosphorus alloy have been intensively studied for the oxygen evolution reaction (OER). Research work has indicated that the presence of phosphorus could lead to the formation of a phosphide/(hydro)-oxide core/shell structure. In this work, we have developed a fabrication technique for a robust NiOOH@amorphous Ni-P bilayer on a zirconia mesh support through the collaboration of electroless deposition and robocasting. During the electroless deposition, a fully amorphous structure can be obtained with a certain phosphorus content (7-8 wt %). Relatively thick films (in the order of 5 μm) had an excellent adhesion on the mesh structure because of the large curvature. A stable Ni oxy/hydroxide surface (∼200 nm) can be formed in bilayer nature (NiOOH/Ni-P) due to preactivation. The combination of catalyst active sites on the surface and high conductivity of metallic body enables good OER performance with an overpotential of 286 mV at a current density of 10 mA cm-2. Together with excellent chemical stability and mechanical strength of the ceramic substrate, this novel combination gives rather excellent adhesion and stability in alkaline solution and provides a different angle for the hierarchical design of corrosion resistant and high-performance OER electrodes for industry.