Electrochemical oxygen reduction is key to many clean and sustainable energy technologies, including proton exchange membrane fuel cells and metal–air batteries. However, the high activation barriers in the oxygen reduction reaction often make it the bottleneck of energy conversion processes; thus, high-performance oxygen reduction electrocatalysts are desired. At present, the best commercially available oxygen reduction catalyst is based on the precious metal Pt. However, it suffers from resource scarcity and unsatisfactory operational stability, hindering its widespread and large-scale application in clean and sustainable technologies. Nitrogen-doped graphene has excellent electrocatalytic properties for oxygen reduction. In this paper, a scalable method to prepare nitrogen-doped graphene with high quality was introduced, in which the graphene oxide prepared by high-gravity technology and urea was reacted under hydrothermal conditions. Accompanying the hydrothermal reaction, graphene oxide reduction and nitrogen doping were accomplished at the same time. The effect of the content of nitrogen on the performance of nitrogen-doped graphene was investigated. When the mass ratio (graphene oxide/urea) was 1:400, the nitrogen-doped graphene had the best oxygen reduction performance. Compared with the undoped samples, the initial reduction voltage of the nitrogen-doped samples distinctly shifted 45 mV to the right. When the voltage was −1.0 V, the electron transfer number was 4.1, indicating good oxygen reduction activity. The preparation method is feasible, simple, and can be easily scaled up.

减少电化学氧气是许多清洁和可持续能源技术的关键，包括质子交换膜燃料电池和金属空气电池。但是，氧还原反应中的高活化势垒常常使它成为能量转化过程的瓶颈。因此，需要高性能的氧还原电催化剂。目前，最好的可商购的氧还原催化剂是基于贵金属Pt的。然而，它遭受资源稀缺和不能令人满意的操作稳定性的困扰，阻碍了其在清洁和可持续技术中的广泛和大规模应用。氮掺杂石墨烯具有出色的电催化氧化还原性能。本文介绍了一种可扩展的制备高质量氮掺杂石墨烯的方法，其中通过高重力技术制备的氧化石墨烯与尿素在水热条件下反应。伴随水热反应，同时完成氧化石墨烯的还原和氮的掺杂。研究了氮含量对掺氮石墨烯性能的影响。当质量比（氧化石墨烯/脲）为1：400时，氮掺杂石墨烯具有最佳的氧还原性能。与未掺杂样品相比，氮掺杂样品的初始还原电压明显向右移动了45 mV。当电压为-1.0V时，电子转移数为4.1，表明氧还原活性良好。该制备方法可行，简单，易于推广。