Oxygen reduction reaction (ORR) has gradually been in the limelight in recent years because of its great application potential for fuel cells and rechargeable metal-air batteries. Therefore, significant issues are increasingly focused on developing effective and economical ORR electrocatalysts. This review begins with the reaction mechanisms and theoretical calculations of ORR in acidic and alkaline media. The latest reports and challenges in ORR electrocatalysis are traced. Most importantly, the latest advances in the development of ORR electrocatalysts are presented in detail, including platinum group metal (PGM), transition metal, and carbon-based electrocatalysts with various nanostructures. Furthermore, the development prospects and challenges of ORR electrocatalysts are speculated and discussed. These insights would help to formulate the design guidelines for highly-active ORR electrocatalysts and affect future research to obtain new knowledge for ORR mechanisms.

氧还原反应（ORR）因其在燃料电池和可充电金属空气电池方面的巨大应用潜力，近年来逐渐受到关注。因此，重要的问题越来越集中在开发有效且经济的 ORR 电催化剂上。本综述从酸性和碱性介质中 ORR 的反应机理和理论计算开始。追溯了 ORR 电催化的最新报道和挑战。最重要的是，详细介绍了 ORR 电催化剂开发的最新进展，包括具有各种纳米结构的铂族金属 (PGM)、过渡金属和碳基电催化剂。此外，对ORR电催化剂的发展前景和挑战进行了推测和讨论。