Abstract
Co–N–C is a promising oxygen electrochemical catalyst due to its high stability and good durability. However, due to the limited adsorption ability improvement for oxygen-containing intermediates, it usually exhibits inadequate catalytic activity with 2-electron pathway and high selectivity of hydrogen peroxide. Herein, the adsorption of Co–N–C to these intermediates is modulated by constructing heterostructures using transition metals and their derivatives based on d-band theory. The heterostructured nanobelts with MoC core and pomegranate-like carbon shell consisting of Co nanoparticles and N dopant (MoC/Co–N–C) are engineered to successfully modulate the d band center of active Co–N–C sites, resulting in a remarkably enhanced electrocatalysis performance. The optimally performing MoC/Co–N–C exhibits outstanding bi-catalytic activity and stability for the oxygen electrochemistry, featuring a high wave-half potential of 0.865 V for the oxygen reduction reaction (ORR) and low overpotential of 370 mV for the oxygen evolution reaction (OER) at 10 mA cm−2. The zinc air batteries with the MoC/Co–N–C catalyst demonstrate a large power density of 180 mW cm−2 and a long cycling lifespan (2000 cycles). The density functional theory calculations with Hubbard correction (DFT + U) reveal the electron transferring from Co to Mo atoms that effectively modulate the d band center of the active Co sites and achieve optimum adsorption ability with “single site double adsorption” mode.
Original language | English |
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Pages (from-to) | 459-469 |
Number of pages | 11 |
Journal | Green Energy and Environment |
Volume | 8 |
Issue number | 2 |
Early online date | 21 May 2021 |
DOIs | |
Publication status | Published - Apr 2023 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2021 Institute of Process Engineering, Chinese Academy of Sciences
Funding
This work was financially supported by the National Natural Science Foundation of China (No. 21975163), the Shenzhen Innovative Research Team Program (KQTD20190929173914967) and the Senior Talent Research Start-up Fund of Shenzhen University (000265). The authors sincerely acknowledge the Instrumental Analysis Center of Shenzhen University (Xili Campus) for HRTEM measurements and analysis.
Keywords
- Bifunctional oxygen catalysts
- D band theory
- Enhanced synergistic effect
- Pomegranate-like shell
- Rechargeable zinc air battery