Preparation and Electrochemical Performance of Macroporous High-Entropy Perovskite Oxide La(Fe 0.25 Ni 0.25 Co 0.25 Mn 0.25 Cr 0.25 )O 3

High-entropy oxides have demonstrated considerable potential for application in the field of nonprecious metal electrocatalysis owing to their distinctive structural and compositional advantages. Herein, macroporous monoliths of La(Fe 0.25 Ni 0.25 Co 0.25 Mn 0.25 Cr 0.25 )O 3 high-entropy perovskite oxide are prepared via a sol-gel process combined with phase separation and subsequent calcination. By precisely tuning the amounts of propylene oxide (PO) and poly(acrylic acid) (PAA), along with a water/glycerol ratio, xerogels featuring interconnected macropores and cocontinuous frameworks are acquired. After calcination, high-entropy perovskite oxides of high purity and superior structural stability are obtained. As synthesized macroporous La(Fe 0.25 Ni 0.25 Co 0.25 Mn 0.25 Cr 0.25 )O 3 calcined at 1000 °C demonstrates exceptional oxygen evolution reaction (OER) catalytic activities under alkaline conditions, with an overpotential of 348 mV at 100 mA cm –2 and a Tafel slope of 42.2 mV dec –1, surpassing commercial IrO 2 under identical testing environment. This work offers interesting insights into the rational design of stable and effective high-entropy perovskite OER catalytic materials.