Abstract The bifunctional catalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are of importance to the development of electrochemical energy systems such as reversible fuel cells, metal-air batteries, and water electrolyzers. Here, using the first-principles methods based on density functional theory (DFT), the Co and N codoped graphene systems (CoNx-gra, x = 1–4) with high ORR activity were further suggested as efficient OER catalysts. It was found that the activity on Co site of CoNx-gra towards ORR and OER would be affected by both the N-dopant concentration and configuration. The extrapolated overpotential of 0.37 V for either ORR or OER on CoNx-gra systems is comparable to those of noble metal benchmark catalysts. The origin of the activity stems from moderate hybridization between Co 3d orbital and p-orbital from O species, governed by the neighboring N coordination environment. Our results highlight the potential application of transition metal and non-metal codoped graphene as efficient non-precious bifunctional catalysts.

中文翻译：

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用于 OER 和 ORR 的双功能 CoN x 嵌入石墨烯电催化剂：理论评估

摘要 用于氧还原反应（ORR）和析氧反应（OER）的双功能催化剂对于可逆燃料电池、金属空气电池和水电解槽等电化学能源系统的发展具有重要意义。在这里，使用基于密度泛函理论（DFT）的第一性原理方法，具有高 ORR 活性的 Co 和 N 共掺杂石墨烯系统（CoNx-gra，x = 1-4）被进一步建议为有效的 OER 催化剂。发现 CoNx-gra 的 Co 位点对 ORR 和 OER 的活性会受到 N 掺杂剂浓度和配置的影响。CoNx-gra 系统上 ORR 或 OER 的外推过电位为 0.37 V，与贵金属基准催化剂的过电位相当。活动的起源源于 Co 3d 轨道和来自 O 物种的 p 轨道之间的适度杂交，由相邻的 N 配位环境控制。我们的结果突出了过渡金属和非金属共掺杂石墨烯作为高效非贵重双功能催化剂的潜在应用。