Four-electron oxygen reduction from mesoporous carbon modified with Fe2O3 nanocrystals

He, Jianan; Li, Binbin; Mao, Jing; Liang, Yanqin; Yang, Xianjin; Cui, Zhenduo; Zhu, Shengli; Li, Zhaoyang

doi:10.1007/s10853-017-1192-5

Cited by 17 publications

(10 citation statements)

References 31 publications

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“…(α‐Fe 2 O 3 ), a mineral with high abundance and stability, has been proven to be active as an electrocatalyst. [ 26,27 ] However, α‐Fe 2 O 3 is seldom used for oxygen reduction in fuel cells because of its sluggish O 2 adsorption and weak capacity for cracking OO bond, [ 28,29 ] suggesting that it may be a potential candidate for the reduction of O 2 to H 2 O 2 . In particular, the {001} facet is expected to be selective for H 2 O 2 production because this surface, which is covered with oxygen atoms, is weak in terms of its capacity for O 2 adsorption and OO cleavage.…”

Section: Introductionmentioning

confidence: 99%

Engineering Facets and Oxygen Vacancies over Hematite Single Crystal for Intensified Electrocatalytic H₂O₂ Production

Gao

Pan

et al. 2020

Adv Funct Materials

110

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Hydrogen peroxide is a highly valuable chemical, and electrocatalytic oxygen reduction towards H2O2 offers an alternative method for safe on‐site applications. Generally, low‐cost hematite (α‐Fe2O3) is not recognized as an efficient electrocatalyst because of its inert nature, but it is herein reported that α‐Fe2O3 can be endowed with high catalytic activity and selectivity via the engineering of facets and oxygen vacancies. Density‐functional theory (DFT)calculations predict that the {001} facet is intrinsically selective for H2O2 production, and that oxygen vacancies can trigger the high activity, providing sites for O2 adsorption and protonation, stabilizing the *OOH intermediate, and preventing cleavage of the OO bond. The synthesized oxygen‐defective α‐Fe2O3 single crystals with exposed {001} facets achieve high selectivities for H2O2 of >90%, >88%, and >95% in weakly acidic, neutral, and alkaline electrolytes, respectively, and the H2O2 production rate reaches 454 mmol g−1cat h−1 at 0.1 V versus RHE under alkaline conditions. In an anion exchange membrane fuel cell, a maximum H2O2 production of 546.8 mmol L−1 with a high Faradaic efficiency of 80.5% is achieved. Thus, this work details a low‐cost catalyst feasible for H2O2 synthesis, and highlights the feasibility of theoretical catalyst design for practical applications.

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Section: Introductionmentioning

confidence: 99%

Engineering Facets and Oxygen Vacancies over Hematite Single Crystal for Intensified Electrocatalytic H₂O₂ Production

Gao

Pan

et al. 2020

Adv Funct Materials

110

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“…For synthesizing mesoporous carbon material, various organic precursors such as furfuryl alcohol, sucrose,,, pitch, pyrene, acenaphthene, phenolic resin, and polyacrylonitrile have been commonly used by researchers from the last decade. Among all, the sucrose is a simple and most convenient source material for preparing mesoporous carbon owing to its highest degrees of lattice contraction yield highly ordered mesoporous structure .…”

Section: Introductionmentioning

confidence: 99%

KIT‐6 Three Dimensional Template Derived Mesoporous Carbon for Oxygen Reduction Reaction: Effect of Template Removal on Catalytic Activity

et al. 2018

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Non precious highly ordered mesoporous carbon (OMC) is of indomitable and perennial catalyst in fuel cells owing to their unique traits and abundant sources. The OMC has been synthesized using KIT-6 sacrificial template and then this removed by three different etching agents, viz, hydrofluoric acid (HF), sodium hydroxide (NaOH) and polyvinylidene fluoride (PVDF). The principle aim of the present work is that to inspect the etched OMCs for oxygen reduction reaction (ORR) activity. In order to understand the effect of etching, we have first studied their fundamental properties. Among three, the HF etched OMC possess comparative surface area (234 m 2 g -1 ), mesoporous sizes (6 nm), large pore volumes (0.13 cm 3 g -1 ) and more accessible defective active sites (I D /I G = 0.90). Hence, the HF etched OMC replica manifest better ORR activity than others in terms of having (0.83 V) onset and (0.71 V) half wave potential, and (2.6 mA/cm 2 at 0.2 V) current density in potassium hydroxide (KOH) electrolyte. From the Nyquist plot, a small semicircle (R ct = 13 Ω cm -2 ) of HF etched OMC substantiates its better ORR activity. A comparative study on etching of OMC using different etching agents could guide to find out a suitable etching agent for modifying the surface properties of OMC.

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“…However, they found that most of the nitrogen was incorporated close to the iron oxide NPs, suggesting the presence of some Fe/N x sites, which leaves the contribution to the iron oxide to the ORR electrocatalysis uncertain. More recently, mesoporous carbon containing Fe 2 O 3 nanocrystals was reported by He et al ., templated with SBA‐15. A comparison with a metal‐free carbon also templated with SBA‐15 as well as pure Fe 2 O 3 showed the superiority of the hybrid material, which the authors attributed to the iron oxide NPs acting as active sites, while the carbon enabled a better mass transport due to is mesoporous structure.…”

Section: Fenx For Electrocatalysismentioning

confidence: 99%

“…More commonly though, findings report a favoured ORR activity for catalysts containing a combination of both, FeN x /C and Fe NPs . Other research also showed enhanced ORR activity in the presence of iron oxide, often as particles, suggesting the latter could also be a probable active site …”

Section: Identification Of Fenx Single Sitesmentioning

confidence: 99%

Homogenous Meets Heterogenous and Electro‐Catalysis: Iron‐Nitrogen Molecular Complexes within Carbon Materials for Catalytic Applications

Nicolae

Qiao

et al. 2019

ChemCatChem

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High activity, selectivity and recyclability are crucial parameters in the design of performant catalysts. Furthermore, depletion of platinum‐group metals (PGM) drives further research towards highly available metal‐based catalysts. In this framework, iron‐based active sites supported on nitrogen‐doped carbon materials (Fe/N@C) have been explored to tackle important applications in organic chemistry, for both oxidation and reduction of C−O/C−N bonds, as well as in electrocatalysis for energy applications. This versatile reactivity makes them ideal substitutes to PGM‐based catalysts, being based on abundant elements. Despite important advances in material science and characterisation techniques allowing the analysis of heterogeneous/electro‐ catalysts at the atomic scale, the nature of the catalytically active sites in Fe/N@C remains elusive. Most recent theoretical studies point at individual FeNx single sites as the origin of the catalytic activity. Although their identification is still challenging with current technology, establishing their real nature will foster further research on these PGM‐free and redox‐polyvalent catalysts. In this review, we provide an overview of their applications in both thermal and electrochemical processes. Throughout the review, we highlight the different characterisation techniques employed to gain insight into the catalyst's active sites.

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Four-electron oxygen reduction from mesoporous carbon modified with Fe2O3 nanocrystals

Cited by 17 publications

References 31 publications

Engineering Facets and Oxygen Vacancies over Hematite Single Crystal for Intensified Electrocatalytic H₂O₂ Production

Engineering Facets and Oxygen Vacancies over Hematite Single Crystal for Intensified Electrocatalytic H₂O₂ Production

KIT‐6 Three Dimensional Template Derived Mesoporous Carbon for Oxygen Reduction Reaction: Effect of Template Removal on Catalytic Activity

Homogenous Meets Heterogenous and Electro‐Catalysis: Iron‐Nitrogen Molecular Complexes within Carbon Materials for Catalytic Applications

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Four-electron oxygen reduction from mesoporous carbon modified with Fe2O3 nanocrystals

Cited by 17 publications

References 31 publications

Engineering Facets and Oxygen Vacancies over Hematite Single Crystal for Intensified Electrocatalytic H2O2 Production

Engineering Facets and Oxygen Vacancies over Hematite Single Crystal for Intensified Electrocatalytic H2O2 Production

KIT‐6 Three Dimensional Template Derived Mesoporous Carbon for Oxygen Reduction Reaction: Effect of Template Removal on Catalytic Activity

Homogenous Meets Heterogenous and Electro‐Catalysis: Iron‐Nitrogen Molecular Complexes within Carbon Materials for Catalytic Applications

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Product

Resources

About

Engineering Facets and Oxygen Vacancies over Hematite Single Crystal for Intensified Electrocatalytic H₂O₂ Production

Engineering Facets and Oxygen Vacancies over Hematite Single Crystal for Intensified Electrocatalytic H₂O₂ Production