The oxygen reduction reaction (ORR) is one of the most important reactions in renewable energy conversion and storage devices. The full deployment of these devices depends on the development of highly active, stable, and low‐cost catalysts. Herein, a new hybrid material consisting of Na₂Ta₈O_21−x /Ta₂O₅/Ta₃N₅ nanocrystals grown on N‐doped reduced graphene oxide is reported. This catalyst shows a significantly enhanced ORR activity by ≈4 orders of magnitude in acidic media and by ≈2 orders of magnitude in alkaline media compared to individual Na₂Ta₈O_21−x on graphene. Moreover, it has excellent stability in both acid and alkaline media. It also has much better methanol tolerance than the commercial Pt/C, which is relevant to methanol fuel cells. The high ORR activity arises not only from the synergistic effect among the three Ta phases, but also from the concomitant nitrogen doping of the reduced graphene oxide nanosheets. A correlation between ORR activity and nitrogen content is demonstrated. Deep insights into the mechanism of the synergistic effect among these three Ta‐based phases, which boosts the ORR's kinetics, are acquired by combining specific experiments and density functional theory calculations.

中文翻译：

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低成本，高活性，耐用的钽酸盐-石墨烯混合电催化剂的氧还原工程

氧还原反应（ORR）是可再生能源转换和存储设备中最重要的反应之一。这些设备的全面部署取决于高活性，稳定和低成本催化剂的开发。本文报道了一种新的杂化材料，该杂化材料由在掺杂N的氧化石墨烯上生长的Na ₂ Ta ₈ O _{21− x} / Ta ₂ O ₅ / Ta ₃ N ₅纳米晶体组成。与单独的Na ₂ Ta ₈ O _{21- x}相比，该催化剂在酸性介质中的ORR活性显着提高了约4个数量级，而在碱性介质中的催化活性显示了约2个数量级。 在石墨烯上。此外，它在酸性和碱性介质中均具有出色的稳定性。与甲醇燃料电池相关的商用Pt / C相比，它具有更好的甲醇耐受性。高ORR活性不仅来自三个Ta相之间的协同效应，还来自还原的氧化石墨烯纳米片的氮掺杂。证明了ORR活性和氮含量之间的相关性。通过结合特定的实验和密度泛函理论计算，获得了对这三个基于Ta的相之间协同效应机理的深刻见解，从而增强了ORR的动力学。