Hierarchical 3D porous trimetallic palladium-iron and cobalt on nickel foam as electrocatalyst for large current density oxygen evolution reaction in alkaline seawater

Abstract

Electrolysis in seawater is a low-cost but difficult method of producing hydrogen. Herein, self-assembled hierarchical three-dimensional (3D) porous trimetallic palladium-iron and cobalt oxide anchored on a cheap and high surface area nickel foam (NF) (PdFeCo3−xO4/NF) were synthesized using a simple and low-cost impregnation-hydrothermal and thermal reduction strategy. The as-fabricated PdFeCo3−xO4/NF electrode showed both superhydrophilic and superaerophobic properties, which favored the fat removal of oxygen bubbles from the electrode surface owing to the close interaction between the electrode and electrolyte. Furthermore, the significant synergistic effect of trimetallics and the NF-matrix resulted in substantially enhanced oxygen evolution reaction (OER) intrinsic activity. The self-assembled PdFeCo3−xO4/NF catalyst exhibited critical low overpotentials of 300 and 340 mV to achieve an extremely large current density of 100 mA cm−2 in 1 M KOH solution and 1 M KOH seawater. Cell voltages as low as 1.44 and 1.51 V were required to drive 10 mA cm−2 in alkaline solution and seawater electrolytes for the full cell overall water splitting performance. This work suggests a promising strategy for developing next-generation electrocatalysts appropriate for natural seawater with cost-effective.