![]() ![]() ![]() The results of pulse voltage induced current (PVC), cyclic voltammetry (CV), density functional theory studies and transient light-induced voltage (TPV) tests showed that the origin of high activity in the Ru 0.5Ir 0.5O 2 catalyst is more Ru active sites with high oxidation states at low applied voltage were formed after Ir incorporation, while increasing the oxidative charge concentration on the surface of the catalyst during the OER process. RHE and a high turnover frequency (TOF) of 6.84 s −1 at 1.44 V vs. In addition, Ru 0.5Ir 0.5O 2 also achieves a high mass activity of 730.4 A g Ir + Ru −1 at 1.44 V vs. When the optimal Ru 0.5Ir 0.5O 2 used as an OER catalyst, it shows excellent OER performance in acidic media, providing an anodic current density of 10 mA cm −2 at an overpotential of only 151 mV, and together with an activity retention time over a 618.3 h stability test at 10 mA cm −2. We show that the stable and oxidative charged Ru two-dimensional RuIr oxides enhance the OER activity significantly. Here, a two-dimensional substitutional solid solution material, phase ruthenium-iridium oxide was successfully synthesized via a two-step molten-alkali process. Designing a RuIr oxide based OER catalyst that can be qualified for both requirements is quite challenging. ![]() One is the stable high oxidation state of the Ru active center, and the other one is to prevent the dissolution and inactivation of Ru species by excessive oxidation. Two sides of requirements must be met by a prospective RuIr oxide-based OER catalyst. Notably, the redox of Ru in RuIr bimetallic oxides could be affected by Ir species in RuIr bimetallic oxides system 13, 19, in which Ru exhibits a strong oxidation state 19, 20, 21, 25, 26, 28. Up to date, the OER catalysts of RuIr bimetallic oxides have been extended from their component-dependence 17, 18, 19, 20, 21, optimization of bimetallic oxide nanostructures (one-dimensional 22, three-dimensional 23 and core-shell structures 24, etc.) to modification of electronic properties 25, 26, 27. The scarcity and relatively low OER activity of Ir are insufficient to meet industrial requirements 13, 14, while, Ru-based catalysts generally suffer from poor stability on account of the formation of soluble Ru oxides (such as RuO 4) during OER process 15, 16. Currently, only Ir-based oxides 5, 6, 7, 8, Ru-based oxides 9, 10, 11, 12 and their derivatives have sufficient corrosion resistance to withstand the harsh acid corrosion and oxidation environments of OER 13. Anodic oxygen evolution reaction (OER) is the bottleneck in the hydrogen production process of water electrolysis 1, 2, 3, 4. ![]()
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