Dual-Phase Spinel MnCo2O4 and Spinel MnCo2O4/Nanocarbon Hybrids for Electrocatalytic Oxygen Reduction and Evolution

• Main Authors: Ge, Xiaoming, Liu, Yayuan, Goh, F. W. Thomas, Hor, T. S. Andy, Zong, Yun, Xiao, Peng, Zhang, Zheng, Lim, Suo Hon, Li, Bing, Wang, Xin, Liu, Zhaolin
• Other Authors: School of Chemical and Biomedical Engineering
• Format: Article
• Language: English
• Published: 2016
• Subjects: Oxygen evolution reaction; Covalent coupling; Oxygen reduction reaction; Transition-metal oxide; Spinel; Nanocarbon; Metal-air battery
• Online Access: https://hdl.handle.net/10356/82074; http://hdl.handle.net/10220/39754
• Institution: Nanyang Technological University

Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential reactions for energy-storage and -conversion devices relying on oxygen electrochemistry. High-performance, nonprecious metal-based hybrid catalysts are developed from postsynthesis integration of dual-phase spinel MnCo2O4 (dp-MnCo2O4) nanocrystals with nanocarbon materials, e.g., carbon nanotube (CNT) and nitrogen-doped reduced graphene oxide (N-rGO). The synergic covalent coupling between dp-MnCo2O4 and nanocarbons effectively enhances both the bifunctional ORR and OER activities of the spinel/nanocarbon hybrid catalysts. The dp-MnCo2O4/N-rGO hybrid catalysts exhibited comparable ORR activity and superior OER activity compared to commercial 30 wt % platinum supported on carbon black (Pt/C). An electrically rechargeable zinc–air battery using dp-MnCo2O4/CNT hybrid catalysts on the cathode was successfully operated for 64 discharge–charge cycles (or 768 h equivalent), significantly outperforming the Pt/C counterpart, which could only survive up to 108 h under similar conditions.