Bimetallic Ir_xCo_1−x alloy nanotubes (x = 0.25, 0.50 and 0.75, the atomic ratios of Ir precursor out of the total metal precursor) were prepared via the thermal H₂-reduction of Ir_xCo_1−xO_y nanotubes which were synthesized by electrospinning and post calcination. Ir and Co atoms were well mixed to form the alloy in Ir_xCo_1−x nanotubes. Their phase structures were different depending on the composition ratios. Ir_0.75Co_0.25 and Ir_0.50Co_0.50 had Ir fcc phase where some Ir atoms were substituted with Co. In contrast, Ir_0.25Co_0.75 was in Ir-substituting Co hcp phase. Among the Ir_xCo_1−x alloy nanotubes, Ir_0.50Co_0.50 showed the highest catalytic activity for overall electrochemical water splitting in acidic, neutral, and alkaline conditions, better than pure metallic Ir and Co counterparts. The activity and stability of Ir_0.50Co_0.50 nanotubes for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) were superior to commercial Ir/C and Pt/C, respectively.

中文翻译：

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铱钴合金纳米管作为双功能电催化剂用于 pH 通用的整体水分解

双金属 Ir _x Co _{1- x}合金纳米管（x  = 0.25、0.50 和 0.75，Ir 前体在总金属前体中的原子比）通过Ir _x Co _{1- x} O _y纳米管的热 H ₂还原制备通过静电纺丝和后煅烧合成。Ir 和 Co 原子充分混合以形成 Ir _x Co _{1- x}纳米管中的合金。它们的相结构根据组成比而不同。Ir _0.75 Co _0.25和 Ir _0.50 Co _0.50具有 Ir fcc 相，其中一些 Ir 原子被Co取代。相反，Ir _0.25 Co _0.75处于 Ir 取代 Co hcp 相。在 Ir _x Co _{1− x}合金纳米管中，Ir _0.50 Co _0.50在酸性、中性和碱性条件下对整体电化学水分解表现出最高的催化活性，优于纯金属 Ir 和 Co 对应物。Ir _0.50 Co _0.50纳米管的析氧反应（OER）和析氢反应（HER）的活性和稳定性分别优于商业化的Ir/C和Pt/C。