For oxygen reduction reaction (ORR), replacing the conventional electrocatalysts based on platinum-group metals (PGMs) with alternatives based on non-noble metals is vital for the large-scale applications of green energy conversion and chemical synthesis. Here, we report the discovery of ORR catalysts based on the p-block-metal bismuth (Bi); the selectivity in ORR pathways could be controlled by tailoring the size of Bi. Specifically, the metallic Bi nanoparticles gave a high selectivity (>96%) for 2e⁻ ORR, an ultra-high kinetic current density (3.8 mA·cm⁻² at 0.65 V), and an excellent stability; in contrast, the single-atomic-site Bi catalysts gave a good selectivity for 4e⁻ ORR and a corresponding half-wave potential of 0.875 V, approaching that of the best-known Fe/NC catalysts. This work presents new high-performance ORR catalysts based on the p-block-metal Bi, in contrast to the intensively studied d-block transition metals, and thus would provide new perspectives for developing PGM-free ORR catalysts.

对于氧还原反应(ORR)，将基于铂族金属 (PGM) 的传统电催化剂替换为基于非贵金属的替代品对于绿色能源转换和化学合成的大规模应用至关重要。在这里，我们报告了基于p嵌段金属铋 (Bi) 的 ORR 催化剂的发现；ORR 途径的选择性可以通过调整 Bi 的大小来控制。^{具体而言，金属铋纳米粒子对 2e - ORR}具有高选择性（>96%）、超高动力学电流密度（0.65 V 时为 3.8 mA·cm ^-2）和出色的稳定性；相比之下，单原子位点 Bi 催化剂对 4e 具有良好的选择性^-ORR 和相应的 0.875 V 半波电位，接近最著名的 Fe/NC 催化剂。与深入研究的d区过渡金属相比，这项工作提出了基于p区金属 Bi的新型高性能 ORR 催化剂，从而为开发不含 PGM 的 ORR 催化剂提供了新的视角。