Improved OER performance of Co3O4/N-CNTs derived from newly designed ZIF-67/PPy NTs composite

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2020-02, Vol.858, p.113768, Article 113768
• Main Authors: Farid, Sumbal, Qiu, Weiwei, Zhao, Jialin, Song, Xuedan, Mao, Qing, Ren, Suzhen, Hao, Ce
• Format: Article
• Language: English
• Subjects: Carbon nanotubes; Charge transfer; Clean energy; Cobalt oxide/carbon material; Cobalt oxides; Electrocatalysts; Fossil fuels; Hydrogen-based energy; Metal organic framework; Nanoparticles; Nitrogen; Oxygen evolution reaction; Oxygen evolution reactions; Polypyrrole nanotubes; Polypyrroles; Reaction kinetics; Synthesis; Water splitting; ZIF-67/PPy NTs composites
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2019.113768

In recent years, a noticeable shifting from conventional fossil fuels to renewable energy based systems has embarked electrochemical splitting of water as the most promising way to produce clean energy of hydrogen. Generally, the lack of active and stable electrocatalysts for oxygen evolution reaction (OER) limits the practicability of water splitting as a renewable source of energy. In this work, interconnected 3D structure of cobalt oxides nanoparticles (Co3O4 NPs) derived from ZIF-67 with nitrogen-doped carbon nanotubes (N-CNTs) of polypyrrole (PPy) origin is successfully synthesized as OER electrocatalysts. Impressively, the highly conductive N-CNTs that run through the Co3O4 NPs not only endow the resulting product Co3O4/N-CNTs with large active surface area and enhanced charge transfer between Co3O4 NPs, but also prevent Co3O4 NPs from aggregation. As a result, the as-synthesized Co3O4/N-CNTs electrocatalyst exhibits outstanding OER activity with a low onset potential of ~1.37 V (vs RHE), overpotential of only 200 mV to attain a stable current density of 10 mA cm−2 in basic media and very small Tafel slope of 40 mV dec−1. Moreover, the enhanced nitrogen-content also improves the OER kinetics by proficient charge transfer. The superb electrocatalytic performance and higher stability make the Co3O4/N-CNTs a proficient non-precious electrocatalyst for the OER. Hierarchically porous interconnected architecture constituted of Co3O4 threaded with Ndoped carbon nanotubes (Co3O4/N-CNTs) was successfully synthesized involving simple carbonization of ZIF-67/PPy NTs to achieve more void active sites for the highly efficient oxygen evolution reaction. Co3O4/N-CNTs exhibited a low overpotential (200 mV) and a small Tafel slope (40 mV dec–1) in 1.0 M KOH. [Display omitted] •Hierarchically porous interconnected network comprised of Co3O4/N-CNTs was prepared.•Large electrochemical surface area owned by Co3O4/N-CNTs led to high electrocatalytic properties.•Co3O4/N-CNTs were evaluated as OER electrocatalysts in alkaline media.•Co3O4/N-CNTs architectures exhibited amazing OER activity and stability.