Electrodeposition of Self-Supported High-Entropy Spinel Oxides for Stable Oxygen Evolution.

Spinel oxides have attracted increasing interest due to their excellent activity in the oxygen evolution reaction (OER). However, despite the high intrinsic OER activity, their poor electrical conductivity and weak structural stability prevented their application for a long time. These shortcomings can be solved by effectively adjusting the electronic structures of spinel oxides through a high-entropy strategy. Herein, a rapid two-step method was developed to prepare self-supported high-entropy spinel-type oxides on a carbon cloth (CC) to yield (Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 Cr 0.2 ) 3 O 4 @CC (abbreviated as FeCoNiMnCr@CC). The unique electronic structure and stable crystal configuration of the resulting FeCoNiMnCr@CC materials required only an overpotential of 287 mV for the OER at a current density of 10 mA cm -2 coupled with excellent cyclic stability. In summary, the proposed high-entropy strategy looks promising for improving the catalytic performance of spinel oxides.