The sluggish kinetics of Oxygen Reduction Reaction (ORR) at the cathode in proton exchange membrane fuel cells or metal-air batteries requires highly effective and stable electrocatalysts to boost the reaction. The low abundance and high price of Pt-based electrocatalysts hamper the widespread application of proton exchange membrane fuel cells and metal-air batteries. As promising alternatives, metal-free carbon materials, especially upon doping heteroatoms or creating defects demonstrated excellent ORR activity, which is as efficient as or even superior to commercial platinum on carbon. Significant progress on the development of advanced carbon materials as highly stable and durable catalysts has been achieved, but the catalytic mechanisms of these materials still remain undistinguished. In present review, we summarized the up-to-date progress in the studies of carbon materials, and emphasized on the combination of experiment and theory to clarify the underlying mechanisms of these materials. At last, we proposed the perspectives on the proper strategies of elucidating the mechanisms of carbon materials as electrocatalysts towards ORR.

质子交换膜燃料电池或金属空气电池中阴极的氧还原反应（ORR）动力学缓慢，需要高效且稳定的电催化剂来促进反应。铂基电催化剂的低丰度和高价格阻碍了质子交换膜燃料电池和金属空气电池的广泛应用。作为有前途的替代品，无金属碳材料，特别是在掺杂杂原子或产生缺陷时，表现出出色的ORR活性，其活性与市售的碳载铂一样有效，甚至优于后者。在高级碳材料作为高度稳定和耐用的催化剂的开发方面已经取得了重大进展，但是这些材料的催化机理仍然没有区别。在目前的评论中，我们总结了碳材料研究的最新进展，并强调通过实验和理论的结合来阐明碳材料的潜在机理。最后，我们对阐明碳材料作为ORR电催化剂机理的正确策略提出了看法。