Corrigendum: Cobalt–Nitrogen‐Doped Helical Carbonaceous Nanotubes as a Class of Efficient Electrocatalysts for the Oxygen Reduction Reaction. Issue 51 (11th December 2018) - Liang, Zuozhong; Fan, Xing; Lei, Haitao; Qi, Jing; Li, Youyong; Gao, Jinpeng; Huo, Meiling; Yuan, Haitao; Zhang, Wei; Lin, Haiping; Zheng, Haoquan; Cao, Rui