Novel Mn-/Co-N x Moieties Captured in N-Doped Carbon Nanotubes for Enhanced Oxygen Reduction Activity and Stability in Acidic and Alkaline Media

Syed Shoaib Ahmad Shah; Tayyaba Najam; Muhammad Sufyan Javed; Mohammed M Rahman; Panagiotis Tsiakaras

doi:10.1021/acsami.1c03477

Novel Mn-/Co-N _x Moieties Captured in N-Doped Carbon Nanotubes for Enhanced Oxygen Reduction Activity and Stability in Acidic and Alkaline Media

ACS Appl Mater Interfaces. 2021 May 19;13(19):23191-23200. doi: 10.1021/acsami.1c03477. Epub 2021 May 10.

Authors

Syed Shoaib Ahmad Shah^{1

2}, Tayyaba Najam^{3

4}, Muhammad Sufyan Javed^{5

6}, Mohammed M Rahman⁷, Panagiotis Tsiakaras^{8

9

10}

Affiliations

¹ Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Soft Matter Chemistry, School of Chemistry and Materials Science, University of Science & Technology of China, Hefei, Anhui 230026, China.
² Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan.
³ Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China.
⁴ College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
⁵ Siyuan Laboratory, Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies & New Energy Materials, Department of Physics, Jinan University, Guangzhou 510632, China.
⁶ School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China.
⁷ Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia.
⁸ Laboratory of Materials and Devices for Clean Energy, Department of Technology of Electrochemical Processes, Ural Federal University, 19 Mira Str., Yekaterinburg 620002, Russia.
⁹ Laboratory of Electrochemical Devices Based on Solid Oxide Proton Electrolytes, Institute of High Temperature Electrochemistry, RAS, Yekaterinburg 620990, Russia.
¹⁰ Laboratory of Alternative Energy Conversion Systems, Department of Mechanical Engineering, School of Engineering, University of Thessaly, Pedion Areos 38834, Greece.

PMID: 33969994
DOI: 10.1021/acsami.1c03477

Abstract

Fe-N-C-based electrocatalysts have been developed as an encouraging substitute compared to their expensive Pt-containing equivalents for the oxygen reduction reaction (ORR). However, they still face major durability challenges from the in- situ production of Fenton radicals. Therefore, the synthesis of Fe-free ORR catalysts is among the emerging concerns. Herein, we have precisely applied a multistep heating strategy to produce mesoporous N-doped carbon nanostructures with Mn-/Co-N_x dual moieties from mixed-metal zeolitic imidazolate frameworks (ZIFs). It is found that their unique structure, with dual-metallic active sites, not only offers a high electrochemical performance for the ORR (E_1/2 = 0.83 V vs reversible hydrogen electrode (RHE) in acid media), but also enhances the operational durability of the catalyst after 20 000 cycles with 97% of retention and very low H₂O₂ production (<5%) in 0.1 M HClO₄. In addition, the catalyst performs well toward the ORR also in alkaline solution (exhibiting E_1/2 = 0.90 V and 30 000 cyclic stability).

Keywords: CNTs; Fe-free catalysts for ORR; fuel cells; metal−organic frameworks (MOFs); zeolitic imidazolate frameworks (ZIFs).