Oxygen Reduction Electrocatalyst Based on Strongly Coupled Cobalt Oxide Nanocrystals and Carbon Nanotubes

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• 作者：Yongye Liang ; Hailiang Wang ; Peng Diao ; Wesley Chang ; Guosong Hong ; Yanguang Li ; Ming Gong ; Liming Xie ; Jigang Zhou ; Jian Wang ; Tom Z. Regier ; Fei Wei ; Hongjie Dai
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：September 26, 2012
• 年：2012
• 卷：134
• 期：38
• 页码：15849-15857
• 全文大小：494K
• 年卷期：v.134,no.38(September 26, 2012)
• ISSN：1520-5126

文摘

Electrocatalyst for oxygen reduction reaction (ORR) is crucial for a variety of renewable energy applications and energy-intensive industries. The design and synthesis of highly active ORR catalysts with strong durability at low cost is extremely desirable but remains challenging. Here, we used a simple two-step method to synthesize cobalt oxide/carbon nanotube (CNT) strongly coupled hybrid as efficient ORR catalyst by directly growing nanocrystals on oxidized multiwalled CNTs. The mildly oxidized CNTs provided functional groups on the outer walls to nucleate and anchor nanocrystals, while retaining intact inner walls for highly conducting network. Cobalt oxide was in the form of CoO due to a gas-phase annealing step in NH₃. The resulting CoO/nitrogen-doped CNT (NCNT) hybrid showed high ORR current density that outperformed Co₃O₄/graphene hybrid and commercial Pt/C catalyst at medium overpotential, mainly through a 4e reduction pathway. The metal oxide/carbon nanotube hybrid was found to be advantageous over the graphene counterpart in terms of active sites and charge transport. Last, the CoO/NCNT hybrid showed high ORR activity and stability under a highly corrosive condition of 10 M NaOH at 80 掳C, demonstrating the potential of strongly coupled inorganic/nanocarbon hybrid as a novel catalyst system in oxygen depolarized cathode for chlor-alkali electrolysis.