Revealing the dependence of active site configuration of N doped and N, S-co-doped carbon nanospheres on six-membered heterocyclic precursors for oxygen reduction reaction

Xiaoran Zhang, Sixian Yao, Pinsong Chen, Yunqiu Wang, Dandan Lyu, Feng Yu, Ming Qing, Zhi Qun Tian, Pei Kang Shen