A Porous Pyrochlore Y₂[Ru_1.6Y_0.4]O_7–δ Electrocatalyst for Enhanced Performance towards the Oxygen Evolution Reaction in Acidic Media

A robust porous structure is often needed for practical applications in electrochemical devices, such as fuel cells, batteries, and electrolyzers. While templating approach is useful for the preparation of porous materials in general, it is not effective for the synthesis of oxide-based electrocatalysts owing to the chemical instability of disordered porous materials thus created. Now the synthesis of phase-pure porous yttrium ruthenate pyrochlore oxide using an unconventional porogen of perchloric acid is presented. The lattice oxygen defects are formed by the mixed-valence state of Ru^4+/5+ through the partial substitution of Ru⁴⁺ with Y³⁺ cations, leading to the formation of mixed B-site Y₂[Ru_1.6Y_0.4]O_7−δ. This porous Y₂[Ru_1.6Y_0.4]O_7−δ electrocatalyst exhibits a turnover frequency (TOF) of 560 s⁻¹ (at 1.5 V versus RHE) for the oxygen evolution reaction, which is two orders of magnitude higher than that of the RuO₂ reference catalyst (5.41 s⁻¹).