Electrocatalytic oxygen reduction via the two-electron pathway (2e-ORR) is an environmentally friendly and promising route for hydrogen peroxide (HO) production. Carbon-based catalysts with transition metal species have been widely investigated due to their high tunability. However, the HO production performance of such catalysts is still far from the requirement of practical applications, owing to their contradiction between durability and ORR activity/selectivity. In this work, metal alloy is encapsulated within the free-standing N-doped carbon nanotube arrays, named NiCo-CNTs- ( represents the duration of the cation substitution process in hours), to precisely regulate the activity and selectivity of nitrogen sites on the surface of the carbon layer, meanwhile hindering the dissolution of alloy inside the CNTs, thus realizing long-term stability and high-activity catalysis for 2e-ORR. Therefore, the NiCo-CNTs-30 demonstrates high activity (onset potential around 0.7 V) and selectivity (greater than 85% within the range of 0–0.8 V), and delivers a high yield of 11.7 mg L h with no current decay or structural damage within 24 h, showcasing its exceptional long-term stability. The catalyst can also effectively degrade organic dyes, making it highly promising for industrial applications.

中文翻译：

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氮掺杂碳纳米管阵列采用钴镍合金封装，作为用于超高速率过氧化氢生产的优质独立式电极

通过双电子途径（2e-ORR）进行电催化氧还原是一种环境友好且有前景的过氧化氢（H2O）生产途径。具有过渡金属物质的碳基催化剂由于其高可调性而得到了广泛的研究。然而，由于其耐久性和ORR活性/选择性之间的矛盾，此类催化剂的H2O生产性能仍远未达到实际应用的要求。在这项工作中，金属合金被封装在独立的氮掺杂碳纳米管阵列中，命名为NiCo-CNTs-（代表阳离子取代过程的持续时间，以小时为单位），以精确调节氮位点的活性和选择性。碳层表面，同时阻碍碳纳米管内部合金的溶解，从而实现2e-ORR的长期稳定性和高活性催化。因此，NiCo-CNTs-30表现出高活性（起始电位约为0.7 V）和选择性（在0-0.8 V范围内大于85％），并提供11.7 mg L h的高产率，且无电流衰减或24 小时内结构损坏，显示出其卓越的长期稳定性。该催化剂还可以有效降解有机染料，使其在工业应用中极具前景。