Abstract The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential to metal-air batteries and fuel cells. Highly efficient and low-cost electrocatalysts for oxygen reactions are in urgent demand. Herein, we synthesized materials through Fe2O3 and NiO depositing on carbon nanotubes (CNTs) by hydrothermal method, which can perform as efficient bifunctional electrocatalysts for the ORR and OER. These catalysts mainly contain macropores which can provide sufficient surface area for active sites. With metal oxides depositing on CNTs, it overcomes some drawbacks such as low conductivity and agglomeration of metal oxides. The catalysts show great electrocatalytic toward ORR and OER even comparing with commercial Pt-C/RuO2 catalysts. Through constructing an air battery and testing the performance of cycling, the stability of the catalyst can also be proved.

中文翻译：

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NiO-Fe 2 O 3 /碳纳米管复合材料作为可充电锌空气电池的双功能电催化剂

摘要 氧还原反应（ORR）和析氧反应（OER）是金属空气电池和燃料电池必不可少的。迫切需要高效、低成本的氧反应电催化剂。在此，我们通过水热法在碳纳米管 (CNT) 上沉积 Fe2O3 和 NiO 合成材料，该材料可以作为 ORR 和 OER 的高效双功能电催化剂。这些催化剂主要包含可以为活性位点提供足够表面积的大孔。通过将金属氧化物沉积在碳纳米管上，克服了导电率低和金属氧化物团聚等缺点。即使与商业 Pt-C/RuO2 催化剂相比，该催化剂也显示出对 ORR 和 OER 的良好电催化。通过构建空气电池并测试骑行性能，