Efficient oxygen electroreduction over ordered mesoporous Co–N-doped carbon derived from cobalt porphyrin

Li, C.; Han, Zhen; Yu, Yan; Zhang, Y.; Dong, Bing; Kong, Aiguo; Shan, Yongkui

doi:10.1039/c5ra25862f

Cited by 28 publications

(11 citation statements)

References 60 publications

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“…2a ). The ORR current density at 0.8 V vs. a reversible hydrogen electrode (RHE) is 0.9 mA cm −2 for a loading of 800 µg cm −2 (12 µg Co cm −2 ), which compares well with state of art Co–N–C catalysts in acid medium, in spite of low cobalt content in Co 0.5 (refs 39 – 41 ). The Pt/C catalyst reaches 1.0 mA cm −2 at 0.91 V vs. RHE, and its higher activity is due to its higher atom-specific ORR activity (the higher Pt loading, 40 µg Pt cm −2 , resulting in identical number of metal atoms per cm 2 as for cobalt, due to the 3.3 times higher molar mass of Pt vs. Co).…”

Section: Resultsmentioning

confidence: 62%

Identification of catalytic sites in cobalt-nitrogen-carbon materials for the oxygen reduction reaction

et al. 2017

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Single-atom catalysts with full utilization of metal centers can bridge the gap between molecular and solid-state catalysis. Metal-nitrogen-carbon materials prepared via pyrolysis are promising single-atom catalysts but often also comprise metallic particles. Here, we pyrolytically synthesize a Co–N–C material only comprising atomically dispersed cobalt ions and identify with X-ray absorption spectroscopy, magnetic susceptibility measurements and density functional theory the structure and electronic state of three porphyrinic moieties, CoN4C12, CoN3C10,porp and CoN2C5. The O2 electro-reduction and operando X-ray absorption response are measured in acidic medium on Co–N–C and compared to those of a Fe–N–C catalyst prepared similarly. We show that cobalt moieties are unmodified from 0.0 to 1.0 V versus a reversible hydrogen electrode, while Fe-based moieties experience structural and electronic-state changes. On the basis of density functional theory analysis and established relationships between redox potential and O2-adsorption strength, we conclude that cobalt-based moieties bind O2 too weakly for efficient O2 reduction.

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Section: Resultsmentioning

confidence: 62%

Identification of catalytic sites in cobalt-nitrogen-carbon materials for the oxygen reduction reaction

et al. 2017

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“…Previous work have demonstrated that the presence of metal-N bond in the metal and nitrogen coexisting system is responsible for the high catalytic activity for the ORR. 54,55 In the work presented here, however, the metal-N bonds are not detected in both the XPS spectra of Co 2p and N 1s, which clearly rules out the presence of the metal-N bond in the Co-CoO@NC/NC-800 and its contribution to the higher catalytic activity of the Co-CoO@NC/NC-800. On the basis of this and the results shown above, we therefore attribute the following aspects to the main reasons responsible for the high catalytic activity of the Co-CoO@NC/NC-800: (1) strong electronic interaction between the Co-CoO nanoparticles and the NC, (2) high specic surface area of the Co-CoO@NC/NC-800, (3) small and uniformly sized Co-CoO nanoparticles, (4) good electric conductivity of the Co-CoO@NC/NC-800 due to its well carbonized structure, (5) good hydrophilicity of the Co-CoO@NC/NC-800 due to the presence of the NC.…”

Section: Electrochemical Measurementcontrasting

confidence: 53%

Core@shell structured Co–CoO@NC nanoparticles supported on nitrogen doped carbon with high catalytic activity for oxygen reduction reaction

et al. 2018

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“…Another important factor regarding to the application as electrocatalyst electrode material is number of electrons transfer during the ORR process 15 . Fig.…”

Section: Resultsmentioning

confidence: 99%

“…For alkaline ORR measurements, loading amount of Pt/C (20%) was ~0.1 mg.cm −2 , which contain loaded Pt quantity of ~20 μg cm −2 . Koutecky-Levich (K-L) relation was used to calculate the kinetic Parameters 15,16 . The mechanism of the mesoporous Fe-doped C12A7:e − composite will be discussed in detail to practically demonstrate that the Fe-doped C12A7:e − composite can exhibit higher electrocatalytic activity towards ORR in the fuel cell.…”

Section: Fe-doped C12a7:e− Composite Synthesismentioning

confidence: 99%

Fe-doped mayenite electride composite with 2D reduced Graphene Oxide: As a non-platinum based, highly durable electrocatalyst for Oxygen Reduction Reaction

Khan

Tareen

Aslam

et al. 2019

Sci Rep

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Since the last decades, non-precious metal catalysts (NPMC), especially iron based electrocatalysts show sufficient activity, potentially applicant in oxygen reduction reaction (ORR), however they only withstand considerable current densities at low operating potentials. On the other hand iron based electrocatalysts are not stable at elevated cathode potentials, which is essential for high energy competence, and its remains difficult to deal. Therefore, via this research a simple approach is demonstrated that allows synthesis of nanosize Fe-doped mayenite electride, [Ca24Al28O64]4+·(e−)4 (can also write as, C12A7−xFex:e−, where doping level, x = 1) (thereafter, Fe-doped C12A7:e−), consist of abundantly available elements with gram level powder material production, based on simple citrate sol-gel method. The maximum achieved conductivity of this first time synthesized Fe-doped C12A7:e− composite materials was 249 S/cm. Consequently, Fe-doped C12A7:e− composite is cost-effective, more active and highly durable precious-metal free electrocatalyst, with 1.03 V onset potential, 0.89 V (RHE) half-wave potential, and ~5.9 mA/cm2 current density, which is higher than benchmark 20% Pt/C (5.65 mA/cm2, and 0.84 V). The Fe-doped C12A7:e− has also higher selectivity for desired 4e− pathway, and more stable than 20 wt% Pt/C electrode with higher immunity towards methanol poisoning. Fe-doped C12A7:e− loses was almost zero of its original activity after passing 11 h compared to the absence of methanol case, indicates that to introduce methanol has almost negligible consequence for ORR performance, which makes it highly desirable, precious-metal free electrocatalyst in ORR. This is primarily described due to coexistence of Fe-doped C12A7:e− related active sites with reduced graphene oxide (rGO) with pyridinic-nitrogen, and their strong coupling consequence along their porous morphology textures. These textures assist rapid diffusion of molecules to catalyst active sites quickly. In real system maximum power densities reached to 243 and 275 mW/cm2 for Pt/C and Fe-doped C12A7:e− composite, respectively.

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Efficient oxygen electroreduction over ordered mesoporous Co–N-doped carbon derived from cobalt porphyrin

Abstract: High-performance self-supported Co–N-doped carbon electrocatalyst for ORR with comparable activity to Pt/C in both acidic and alkaline media was prepared.

Cited by 28 publications

References 60 publications

Identification of catalytic sites in cobalt-nitrogen-carbon materials for the oxygen reduction reaction

Identification of catalytic sites in cobalt-nitrogen-carbon materials for the oxygen reduction reaction

Core@shell structured Co–CoO@NC nanoparticles supported on nitrogen doped carbon with high catalytic activity for oxygen reduction reaction

Fe-doped mayenite electride composite with 2D reduced Graphene Oxide: As a non-platinum based, highly durable electrocatalyst for Oxygen Reduction Reaction

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