Three-dimensional ordered macroporous design of heterogeneous cobalt-iron phosphides as oxygen evolution electrocatalyst

Abstract Oxygen evolution reaction (OER) plays a key role in electrochemical conversion, which needs efficient and economical electrocatalyst to boost its kinetics for large-scale application. Herein, a bimetallic CoP/FeP2 heterostructure with a three-dimensional ordered macroporous structure (3DOM-CoP/FeP2) was synthesized as an OER catalyst to demonstrate a heterogeneous engineering induction strategy. By adjusting the electron distribution and producing a lot of active sites, the heterogeneous interface enhances catalytic performance. High specific surface area is provided by the 3DOM structure. Additionally, at the solid-gas-electrolyte threephase interface, the electrocatalytic reaction exhibits good mass transfer. In-situ Raman spectroscopy characterization revealed that FeOOH and CoOOH reconstructed from CoP/FeP2 were the true OER active sites. Consequently, the 3DOM-CoP/FeP2 demonstrates superior OER activity with a low overpotentials of 300/420 mV at 10/100 mA cm–2 and meritorious OER durability. It also reveals promising performance as the overall water splitting anode.