Enhancing the catalytic activity of manganese oxide in oxygen reduction reaction (ORR) is a key issue for its large-scale application in metal-air fuel cells. Ag-doped [Formula: see text]-MnO2 nanowires without Ag or Ag2O have been successfully synthesized via a facile hydrothermal method, and the changes in both the structure and electrochemical catalytic performances after Ag doping are investigated. Compared with the pristine [Formula: see text]-MnO2, the as-prepared Ag-doped MnO2 exhibits a significantly enhanced catalytic activity in both ORR and Mg-air fuel cell application. With Ag/Mn ratio of 1:25, Ag-doped MnO2 exhibits a typical 4e-reaction pathway and presents a 163 mV higher half-wave potential than that of the pristine [Formula: see text]-MnO2. Furthermore, it demonstrates a power density of 75.1[Formula: see text]mW[Formula: see text]cm[Formula: see text] at current density of 134.5[Formula: see text]mA[Formula: see text]cm[Formula: see text] in the Mg-air fuel cells. The enhanced ORR performances are considered to be contributed from the activation of surface lattice oxygen, the improvement in conductivity and the increase in oxygen vacancies of [Formula: see text]-MnO2. These findings provide new understanding for developing high-performance manganese oxide catalysts.

中文翻译：

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Ag掺杂增强α-MnO2纳米线的氧还原反应活性

提高锰氧化物在氧还原反应（ORR）中的催化活性是其在金属-空气燃料电池中大规模应用的关键问题。Ag掺杂[分子式：见正文]-MnO2不含 Ag 或 Ag 的纳米线2通过简便的水热法成功合成了O，并研究了Ag掺杂后结构和电化学催化性能的变化。与原始的[公式：见正文]-MnO相比2, 制备的 Ag 掺杂 MnO2在 ORR 和镁空气燃料电池应用中表现出显着增强的催化活性。Ag/Mn 比为 1:25，Ag 掺杂的 MnO2表现出典型的 4e 反应途径，并呈现出比原始 [公式：见正文]-MnO 高 163 mV 的半波电位2. 此外，在电流密度为 134.5[公式：见文本]mA[公式：见文本]cm[公式: 见正文] 在镁空气燃料电池中。增强的 ORR 性能被认为是由于表面晶格氧的活化、电导率的提高和 [分子式：见正文]-MnO 的氧空位增加2. 这些发现为开发高性能氧化锰催化剂提供了新的认识。