Ti3+-self-doped TiO2 with multiple crystal-phases anchored on acid-pickled ZIF-67-derived Co3O4@N-doped graphitized-carbon as a durable catalyst for oxygen reduction in alkaline and acid media

Yu Yang, Shijie You, Jiannan Du, Peng Zhang, Ying Dai, Mingyang Liu, Baojiang Jiang, Nanqi Ren, Jinlong Zou