Synergistic effects in oxygen evolution activity of mixed iridium-ruthenium pyrochlores

Spin-related symmetry breaking induced by half-disordered hybridization in BixEr2-xRu2O7 pyrochlores for acidic oxygen evolution

“…Inspired by this consideration, spin-related symmetry breaking induced by atomic disordered-hybridization becomes an intriguing and feasible strategy to design new-type catalysts with higher reactive activity and electrochemical stability. It is important to note that this proposal is completely different from traditional doping strategy as recent reports 3 , 11 , 16 , 19 . They are as follows: (1) the host elements can be partially replaced by traditional doping atoms but that cannot lead to a controllable structural symmetry breaking; (2) the metal cations acting as active sites have been completely coordinated by the nearest-neighboring anions, which makes it cannot directly generate super-exchange interaction with metal dopants.…”

Material design and surface chemistry for advanced rechargeable zinc–air batteries

“…36,37 Nevertheless, the less active but more stable IrO 2 is used as the benchmark electrocatalyst for application. 38,39 However, the conventional PGM electrocatalysts have the following intrinsic problems, such as scarcity of resources, low stability, detachment from support materials, and CO poisoning. Thus, the practical applications of ZABs have been greatly hindered, and the utilization for a large-scale energy storage system is also limited.…”

Exploiting the flexibility of the pyrochlore composition for acid-resilient iridium oxide electrocatalysts in proton exchange membranes

“…This is consistent with recent work on mixed iridium-ruthenium pyrochlores of some lanthanides. 31 XANES analysis at the Ru K-edge (ESI †) shows that both metals have an average oxidation state close to +4.5, so the smaller size of Ru 4+ and Ru 5+ compared to the Ir 4+/5+ must be responsible for the lattice contraction. In the case of Rh, only smaller amounts can be substituted, up to y ¼ 0.3, with evidence of a lattice expansion: this would be consistent with the larger size of Rh 3+ or Rh 4+ , and the difficulty in oxidising Rh to the higher oxidation state may be the reason why only a limited amount can be included in the structure.…”