Porous amorphous high entropy oxide coated dimensionally stable anode for oxygen evolution reaction in acidic media

Abstract

Oxygen evolution reaction (OER) has been the subject of considerable attention as a pivotal reaction in the hydrogen production and hydrometallurical electrowinning. Precious metal-coated dimensionally stable anodes (DSAs) have wide applications in electrochemical industry, functioning as high-performance and stable electrocatalysts for OER. Given the broad development prospects opened up by the advocacy of green energy, the key to the electrochemical industry lies in improving the catalytic performance and durability of DSA. In this study, a novel porous amorphous Ir-based high-entropy oxides-coated DSA was prepared by thermal decomposition method, and its OER activity and durability in acidic media were investigated. The Ir-based high-entropy oxides coatings exhibit a hierarchical porous morphology at the surface, coupled with an amorphous structure. The coatings display a high proportion of Ir3+, unsaturated bonds and oxygen vacancies/hydroxyl groups, which collectively impart excellent OER activity. The achievement of current densities of 10 and 100 mA cm⁻² at potentials of 1.45 and 1.51 V vs. RHE in 0.5 mol L⁻¹ H₂SO₄ solution represents a significant outcome. The coatings demonstrated remarkable electrochemical durability without decay after 5000 cycles and are able to withstand a cumulative 504-hour durability test under the current density of 1000, 2000, and 3000 mA cm⁻².