Cobalt Single Atoms Immobilized N-Doped Carbon Nanotubes for Enhanced Bifunctional Catalysis toward Oxygen Reduction and Oxygen Evolution Reactions

Abstract

Novel Co atoms immobilized carbon nanotubes (CoSAs@CNTs) are synthesized by structural engineering of the zeolitic imidazolate framework (ZIF-67) upon treatment with dicyandiamide (DCD). A unique morphology and promising electrochemical performance are shown by the Co atoms immobilized CNTs. The electrocatalyst remarkably exhibits a highly positive onset potential of 0.99 V and half-wave potential of 0.86 V, both even more positive than the commercial Pt/C catalyst, and the current density is also greater than that of the Pt/C catalyst in alkaline media. A decent performance is observed in acidic media also. The electrocatalyst is extraordinarily stable to harsh environments. A promising performance for the oxygen evolution reaction (OER) is demonstrated by the electrocatalyst, while for bifunctional electrocatalysis a small overvoltage of 0.78 V is observed with onset potential at the lower overpotential of 300 mV announcing the advantage of its usage for practical energy conversion and storage systems. This novel study may provide a new road map for fuel cell technology.

Atomic Layer Deposition‐Assisted Fabrication of Co‐Nanoparticle/N‐Doped Carbon Nanotube Hybrids as Efficient Electrocatalysts for the Oxygen Evolution Reaction

“…The incorporation of Co into an N–C matrix can significantly affect the overall chemical environment of carbon hybrids. [ 25 ] Specifically, as the charge density of carbon in Co–N–C bridges is expected to be more positive than that in N–C bonds, carbons in such bridges may attract more hydroxyl ions or electrons because of their high electrophilicity to enhance water oxidation kinetics. Hence, for Co/N‐CNTs, the increase in the number of pyridinic N sites along with the incorporation of Co into the carbon matrix with increasing H 2 flow rate afforded multiple active sites and simultaneously facilitated charge transfer to enhance OER catalytic performance.…”

“…Thus, Co−N−C species can be easily formed in carbon matrix assisted by pyridinic‐N, which can function as a real active site for electrocatalytic reaction. [ 25,26 ]…”

Cobalt Nanoparticles and Atomic Sites in Nitrogen‐Doped Carbon Frameworks for Highly Sensitive Sensing of Hydrogen Peroxide

“…Traditional synthesis methods such as chemical vapor deposition (CVD) involve severe conditions and are difficult to control due to the introduction of small‐molecule gases (e.g., NH 3 , H 2 ) . Therefore, developing a simple solid‐phase synthetic strategy to improve both the conductivity and nitrogen content under common conditions will be more beneficial and attractive for developing MOF‐derived M–N/C electrocatalysts with more active sites …”

Cobalt Nanoparticles Encapsulated in Nitrogen-Doped Carbon Nanotube as Bifunctional-Catalyst for Rechargeable Zn-Air Batteries

“…The specific contents of all elements are summarized in Table S1. The high resolution C1s spectrum were deconvoluted into three peaks ( Figure S7a): C-C (284.6 eV), C-O (285.4 eV), and C=O (286.5 eV) (Dilpazir et al, 2018). The high resolution C1s spectrum ( Figure 2C) exhibits four types of N species at 398.5, 400.1, 401, 403.6 eV, which correspond to pyridinic N, pyrrolic N, graphitic N, and oxidized N (Zhao and Chen, 2015;Fang et al, 2016a;Zhou T. et al, 2017).…”

“…Jie et al published a one-pot pyrolysis method to obtained N-doped carbon nanotubes encapsulated the synthesized nickel-cobalt alloy, which has high catalytic performance. Yang et al designed a synthetic strategy using FeCl 3 /NH 3 as the source to obtain Fe-N-C catalyst by heat-treating defective graphene at 950 • C. Dilpazir et al synthesized novel Co nanoparticles immobilized NCNTs on the zeolitic imidazolate framework treated with dicyandiamide Jie et al, 2017;Li et al, 2017;Song et al, 2017;Dilpazir et al, 2018). However, in these experiments, the introduction of a template or the use of ammonia gas increased the cost and risk of the experiment.…”