Rutile‐Structured (RuSnSbReF)Ox High Entropy Solid Solution for Acidic Oxygen Evolution Reaction

Abstract Developing efficient and low‐cost electrocatalysts with exceptional durability and electrocatalytic activity for the acidic oxygen evolution reaction (OER) presents a significant challenge, primarily owing to the irreversible dissolution of the electrocatalysts in acidic electrolytes. Here, a rutile‐structured (RuSnSbReF)O x high entropy solid solution is successfully fabricated on the substrate of corrosion‐resistant titanium via a high‐temperature sintering technique. The (RuSnSbReF)O x electrocatalyst for the OER achieves a super‐low overpotential of 156 mV and a small Tafel slope of 23.87 mV dec −1 at a current density of 10 mA cm −2 in a 0.5 M H 2 SO 4 solution. A high‐stable operation potential is performed for the long‐term measurement of 213 h at a current density of 100 mA cm −2 . There is a lower energy barrier of the rate‐determining step (RDS) on the Ruthenium (Ru)‐Rhenium (Re) bridge site of the (RuSnSbReF)O x electrocatalyst in comparison with that of other sites for acidic OER. The reservoir‐like Re species in the (RuSnSbReF)O x can bestow/save the electrons to the Ru site through O‐bridges, favorably adjusting the electronic structure and the oxidation state. This investigation opens a feasible avenue to develop an efficient and durable Ru‐based electrocatalysts of rutile‐structured high entropy solid solution for the OER toward the practical applications of electrochemical industry in acidic media.