Effects of A‐site Cations in Quadruple Perovskite Ruthenates on Oxygen Evolution Catalysis in Acidic Aqueous Solutions

Abstract

The quadruple perovskite ruthenate CaCu3Ru4O12 is more active and stable than the benchmark catalyst RuO2 in the oxygen evolution reaction (OER) in acidic aqueous solutions, where many oxide‐based catalysts are dissolved. Studies on the crystal structures of quadruple perovskite ruthenates are rare, and the origin of OER activity or stability from a structural aspect has not been clarified in detail. This presents the need to study the effects of cations at the A site of quadruple perovskite ruthenates ACu3Ru4O12 (A = Ca, Sr, La, Nd, and Ce) on the OER catalytic activity and stability in acidic aqueous solutions. CaCu3Ru4O12 has the highest activity and stability among all quadruple perovskite samples. The type of cation at the A site changes the average Cu and Ru valence states, and the plot of OER activity versus the average Cu valence number shows a volcano‐type relationship. In addition, stability increases with a decrease in Ru–O bond length. This research provides a good design principle for OER catalysts with high activity and stability in severely acidic aqueous solutions.

Regulation engineering of the surface and structure of perovskite-based electrocatalysts for the oxygen evolution reaction

“…Shunsuke Yagi et al further investigated the effect of A-site cations on the catalytic activity and stability of ACu 3 Ru 4 O 12 (A= Ca, Sr, La, Nd, Ce) in acidic aqueous solution. 125 The different cations at A-sites change the average valence states of Cu and Ru and the bond length of Ru–O. The relationship between the activity of the OER and average Cu valence shows a volcanic type relationship (Fig.…”

“…Where hA-Oi and hB-Oi are the main distances of ABO 3 molecular perovskite. 126 125 The different cations at A-sites change the average valence states of Cu and Ru and the bond length of Ru-O. The relationship between the activity of the OER and average Cu valence shows a volcanic type relationship (Fig.…”

“…(e) A graph showing the relationship between the length of the Ru-O bond and the ratio of current density i 100 /i 1 at the 100th and 1st cycles. Reproduced with permission 125. Copyright 2022, Wiley-VCH GmbH.…”

Nanoelectrocatalysts for Anodic Oxygen Evolution in Acid: A Review

“…Copyright 2020 American Chemical Society. (w) Crystal structure of ACu 3 Ru 4 O 12 . (x) Average Cu valence state and specific activity i1 in OER catalysis at 1.55 V vs RHE for ACu 3 Ru 4 O 12 at the first cycle in the LSVs .…”

Atomically Dispersed V‐O2N3 Sites with Axial VO Coordination on Multichannel Carbon Nanofibers Achieving Superior Electrocatalytic Oxygen Evolution in Acidic Media

“…[1][2][3][4] Following the roadmap toward the carbon-neutrality, protonexchange membrane (PEM) water electrolysis in acidic media, which can be powered by temporally/spatially intermittent sustainable energy (e.g., solar energy, wind, and tide), has been considered as a promising technology for large-scale hydrogen production due to the low Ohmic resistance, minimized current loss, and high operation efficiency. [5][6][7] More attractively, the acidic electrolyzer generally exhibits several orders of magnitude in reaction rates as compared with those of the alkaline and neutral counterparts. [8,9] However, as a key half-reaction, the anodic oxygen evolution reaction (OER) is a four-proton-coupled electron-transfer process with inherently sluggish kinetics, necessitating a much higher overpotential to overcome the kinetic barrier than the two electron-transfer hydrogen evolution reaction on the cathode.…”