The design and development of highly active non-noble metal electrocatalysts for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are crucial for metal-air batteries. In this work, the electrocatalytic performance of different p-block metal (PM = Sn, Sb, Pb and Bi) atoms embedded in the g-CN monolayer (PM_x@g-CN, x = 1–3) for the OER and ORR was systematically investigated by density functional theory (DFT). The strong interaction between PM_x atoms and g-CN substrates indicates the good stability of PM_x@g-CN catalysts. Among all the designed catalysts, Bi₃@g-CN is found to be a promising bifunctional electrocatalyst for both the OER and ORR with the calculated overpotential η^OER and η^ORR of 0.23 and 0.25 V, respectively. With the atomic active sites of PM_x increasing from x = 1 to 3, the OER and ORR catalytic activity is enhanced. The correlations between the overpotentials of the OER/ORR and Bader charge values of the anchored PM_x atoms of the catalysts were established. Our findings contribute to searching for noble metal-free bifunctional electrocatalysts and shed light on the rational design of atomic active sites on electrocatalysts.

中文翻译：

---

锚定在 g-CN 单层上的单、双和-嵌段金属用于氧电催化的理论研究


用于析氧反应 （OER） 和氧还原反应 （ORR） 的高活性非贵金属电催化剂的设计和开发对于金属空气电池至关重要。在这项工作中，通过密度泛函理论 （DFT） 系统研究了嵌入 g-CN 单层 （PM_x@g-CN， x = 1–3） 中的不同 p 嵌段金属 （PM = Sn、Sb、Pb 和 Bi） 原子对 OER 和 ORR 的电催化性能。PM_x 原子与 g-CN 底物之间的强相互作用表明 PM_x@g-CN 催化剂具有良好的稳定性。在所有设计的催化剂中，Bi₃@g-CN 被发现是一种很有前途的 OER 和 ORR 双功能电催化剂，计算η^OER 和 η^ORR 的过电位分别为 0.23 和 0.25 V。随着 PM_x 的原子活性位点从 x = 1 增加到 3，OER 和 ORR 催化活性增强。建立了 OER/ORR 的过电位与催化剂锚定 PM_x 原子的 Bader 电荷值之间的相关性。我们的发现有助于寻找无贵金属的双功能电催化剂，并阐明电催化剂上原子活性位点的合理设计。