A novel, low-cost, and powerful cerium-oxide nanowire (CeO₂NW) electrode decorated with graphite felt (GF) through a one-step hydrothermal method was proposed in this study. Subsequently, hydrogen annealing was conducted to create defective-hydrogen-annealed CeO₂NWs decorated with GF (H–CeO₂NWs–GF) for use in vanadium redox flow batteries (VRFBs). The electrochemical results show that the H–CeO₂NWs–GF reveals excellent electrocatalytic effects toward the VO₂⁺/VO²⁺ redox process in VRFBs at the positive electrode to facilitate the electrochemical kinetics of the VRFBs. The VRFBs using different electrode materials were compared with a VRFB using H–CeO₂NWs–GF. The results revealed that the VRFB using H–CeO₂NWs–GF exhibits the highest voltage efficiency of 90.4% at a current density of 40 mA cm^–2, which is significantly higher than those using pristine GF (81.1%) and a CeO₂NW electrode decorated with GF (88.4%). The significant improvement in the electrochemical performance of H–CeO₂NWs–GF might be mostly ascribed to the defect-rich H–CeO₂NWs on the GF surface, which acts as active sites and reduces the electrochemical polarization of the redox reaction. Moreover, the one-dimensional nature of H–CeO₂NWs is favorable for the charge-transfer process and improves the accessibility, thus improving the electrode performance.

中文翻译：

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富氧空缺立方CeO ₂纳米线作为钒氧化还原液流电池的催化剂

提出了一种新颖，低成本，功能强大的氧化铈纳米线（CeO ₂ NW）电极，该电极通过一步水热法装饰了石墨毡（GF）。随后，进行氢退火以产生缺陷氢退火的CeO ₂ NW，并用GF装饰（H–CeO ₂ NWs–GF），用于钒氧化还原液流电池（VRFB）。电化学结果表明，H–CeO ₂ NWs–GF在正极上对VRFBs的VO ₂ ⁺ / VO ²⁺氧化还原过程显示出优异的电催化作用，从而促进了VRFBs的电化学动力学。将使用不同电极材料的VRFB与使用H–CeO ₂的VRFB进行比较NWs-GF。结果表明，使用H–CeO ₂ NWs –GF的VRFB在40 mA cm ^–2的电流密度下显示出最高的电压效率90.4％，这明显高于使用原始GF（81.1％）和CeO ₂ NW电极装饰有GF（88.4％）。H–CeO ₂ NWs–GF电化学性能的显着改善可能主要归因于GF表面上的富缺陷H–CeO ₂ NWs，它们充当活性位点并减少了氧化还原反应的电化学极化。此外，H–CeO ₂ NW的一维性质有利于电荷转移过程，并改善了可及性，从而改善了电极性能。