Regular-Hexahedron-Shaped Iron–Copper Bimetallic Oxides Engineered on Plasma-Treated Iron Foam for Enhanced Electrocatalytic Oxygen Evolution in an Alkaline Medium
Tao Sun, Guangliang Chen, Yingchun Guo, Tongtong Li, Bin He, Peisong Tang
Abstract
Designing a highly efficient transition-metal-based electrocatalyst for the oxygen evolution reaction (OER) in an alkaline electrolyte by a green and low-cost protocol is still facing many challenges. Herein, a regular-hexahedron-shaped iron–copper oxide (CuFe 2 O 4 –Fe 2 O 3 ) is engineered on plasma-treated iron foam (PFF) with a one-step hydrothermal process. Benefiting from the formed rich heterointerfaces, the obtained CuFe 2 O 4 –Fe 2 O 3 /PFF exhibits an outstanding OER activity and stability in the alkaline medium, and the overpotential for delivering a current density of 10 mA cm –2 ( j 10 ) is only 190 mV. Meanwhile, thanks to the micronized hexahedron profile, CuFe 2 O 4 –Fe 2 O 3 /PFF also shows an excellent electrocatalytic stability, and the OER activity decays only 8% after a 90 h OER test under a high current density ( j 100 ). Furthermore, the theory calculation (DFT) indicates that Fe sites exposed on the heterointerface of CuFe 2 O 4 and Fe 2 O 3 are the main active centers for O 2 evolution in an alkaline medium.