Abstract Electrochemical oxygen evolution reaction plays a pivotal role in various clean energy conversion and storage systems for producing alternative energy sources. In this work, we have successfully synthesized a novel heterostructure material of snowflake-like Co3O4 nanomaterials attaching on the tip of CuO nanorod arrays supported on three-dimensional copper foam via facile and effective approach. The obtained Co3O4-CuO NRs/CF has been used as efficient electrocatalyst for accelerating the oxygen evolution reaction in alkaline condition, in which a very low overpotential of 340 mV, which was even lower than that of the benchmark RuO2 catalyst, was required to achieve a current density of 20 mA cm−2, together with a small Tafel slope value of 73.3 mV dec−1. The unique heterostructure and excellent mesoporous characteristic of the Co3O4-CuO NRs/CF materials were the main reasons for its large electrochemical active surface area. Furthermore, the Co3O4-CuO NRs/CF exhibited a much higher electrocatalytic activity than those of the CuO NRs/CF (384 mV at 20 mA cm−2, 139.6 mV dec−1) and Co3O4/CF (360 mV at 20 mA cm−2, 95.3 mV dec−1), as its courterparts. This deomstrated that formation of hetorostructure between snowflake Co3O4 and CuO NRs resulting in enhancing OER performance. In addition to excellent catalytic activity, this catalyst also showed remarkable stability toward the oxygen evolution reaction for at least 30 h under constant potential of 1.6 V in the alkaline condition. The highly catalytic performance for the OER reaction was ascribed to the merits of a unique heterostructure, 3D nanoarrays feature and the synergistic effect between Co3O4 and CuO.

中文翻译：

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雪花 Co3O4-CuO 异质阳极阵列支持三维框架以增强析氧能力

摘要 电化学析氧反应在用于生产替代能源的各种清洁能源转换和存储系统中起着举足轻重的作用。在这项工作中，我们通过简便有效的方法成功合成了一种新型的雪花状 Co3O4 纳米材料异质结构材料，该材料附着在支撑在三维泡沫铜上的 CuO 纳米棒阵列的尖端。获得的 Co3O4-CuO NRs/CF 已被用作在碱性条件下加速析氧反应的有效电催化剂，其中需要 340 mV 的非常低的过电位，甚至低于基准 RuO2 催化剂的过电位，以实现20 mA cm-2 的电流密度，以及 73.3 mV dec-1 的小塔菲尔斜率值。Co3O4-CuO NRs/CF 材料独特的异质结构和优异的介孔特性是其电化学活性表面积大的主要原因。此外，Co3O4-CuO NRs/CF 表现出比 CuO NRs/CF（20 mA cm-2 时 384 mV，139.6 mV dec-1）和 Co3O4/CF（20 mA cm-3 时 360 mV）更高的电催化活性。 −2, 95.3 mV dec−1)，作为它的伴侣。这证明了雪花 Co3O4 和 CuO NR 之间的异质结构的形成，从而提高了 OER 性能。除了优异的催化活性外，该催化剂还在碱性条件下在 1.6 V 的恒定电位下对析氧反应显示出显着的稳定性至少 30 小时。OER 反应的高催化性能归因于独特的异质结构的优点，