In recent years, metal isolated site catalysts with the high exposure and maximized availability of metal species provide a new route to boost the oxygen reduction performance. However, in the absence of clusters and nanoparticles, the synthesis of this catalyst with metal high-loading, especially for copper, is still a big challenge. In this work, a metal isolated site catalyst with high copper content (1.12 wt %), copper isolated sites anchored on N-doped carbon materials (donated as Cu ISs/NC-1000), was prepared by the pyrolysis of copper acetylacetone within the metal–organic framework (ZIF-8) at 1000 °C. The successful preparation of products can be demonstrated by high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption spectra. With the merits of the atomically dispersed surface metal atoms and abundant ORR-favored copper active sites, the present Cu ISs/NC-1000 exhibits an excellent ORR electrochemical activity with a half-wave potential of 0.855 V (vs RHE) and a limiting current density of 5.2 mA cm^–2 in the electrochemical tests, superior to the results from commercial Pt/C and previously reported Cu-based materials. For the durability, the negligible activity decay after 10,000 continuous potential cycles and good resistance to methanol crossover can be noted. The outstanding catalytic activity from the present Cu ISs/NC-1000 demonstrates the superiority of metal isolated sites as electrocatalytic centers.

中文翻译：

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N掺杂碳纳米框架上的铜隔离位点，可有效减少氧气

近年来，金属隔离位催化剂具有高暴露度和金属种类的最大利用率，为提高氧还原性能提供了一条新途径。然而，在没有团簇和纳米颗粒的情况下，具有金属高载量，特别是对于铜的这种催化剂的合成仍然是巨大的挑战。在这项工作中，通过对乙酰丙酮铜进行热解制备了具有高铜含量（1.12 wt％），锚定在掺氮碳材料上的铜分离位点（捐赠为Cu ISs / NC-1000）。金属-有机骨架（ZIF-8）在1000°C下。通过高角度环形暗场扫描透射电子显微镜和X射线吸收光谱可以证明产品的成功制备。电化学测试中的^–2优于商用Pt / C和先前报道的基于铜的材料的结果。对于耐久性，可以注意到在10,000个连续电势循环后活性可忽略不计，并且具有良好的耐甲醇穿透性。当前的Cu ISs / NC-1000具有出色的催化活性，证明了金属分离位点作为电催化中心的优越性。