Revealing the defect-dominated oxygen evolution activity of hematene

Mohanty, Bishnupad; Wei, Yidan; Ghorbani‐Asl, Mahdi; Krasheninnikov, Arkady V.; Rajput, Parasmani; Jena, Bikash Kumar

doi:10.1039/d0ta00422g

Cited by 63 publications

(43 citation statements)

References 52 publications

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“…Liquid exfoliated Fe 2 O 3 modified through defect engineering increases the number of active sites involving surface oxygen. [ 139 ] It provides flexible structure and increased conductivity, which results in a reduction of the potential barrier in OER process. It is widely accepted that doping with redox active cations such as Co and Ni into lattice can significantly improve the catalytic performance.…”

Section: Transition Metal‐based Oer Electrocatalystsmentioning

confidence: 99%

Advanced Transition Metal‐Based OER Electrocatalysts: Current Status, Opportunities, and Challenges

Zhang

Zou

2021

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and sustainable energy sources, which have been considered as an encouraging solution to significantly reduce the dependency on traditional fossil fuels. Hydrogen is a promising clean energy carrier by virtue of zero-carbon content and the highest gravimetric energy density. [1] In this scenario, hydrogen production through electricity-driven water splitting represents a promising strategy for renewable energy conversion.Water electrolysis involves hydrogen evolution reaction (HER) on cathode and oxygen evolution reaction (OER) on anode. Theoretically, it requires a potential difference of 1.23 V between anode and cathode for driving the overall reaction. [2] But actually, a much higher voltage is needed in a practical water electrolyzer due to the overpotentials on both electrodes. HER is a relatively simple two-electron transport process involving electrochemical H + adsorption and desorption of H 2 . In contrast, OER is an inherently more complex process and has sluggish oxygen evolution kinetics, since it needs to transfer four electrons through multi-step reactions with single-electron transfer at each step. [3] As a result, the accumulation of energy at each step makes OER kinetically hindered and a large overpotential is needed to overcome the kinetic energy barrier. On the other hand, OER is an important half reaction involved in rechargeable metal-air batteries which are also regarded as the emerging sustainable energy conversion technology. Nevertheless, the bottlenecks such as low lifetimes, inferior energy conversion efficiency, and limited stability of metal-air batteries mainly originate from the intrinsically sluggish kinetics of OER. [4] Hence, developing effective and stable OER electrocatalysts by improving oxygen electrokinetics can significantly contribute to improving energy-conversion efficiency.To date, transition metal-based OER catalysts have been extensively studied by virtue of their excellent OER catalytic activities. [5] Noble-metal-based electrocatalysts have been considered as the most powerful electrocatalysts for OER in spite of their high prices. Among them, Ru and Ir have been verified to outperform Pt, Pd, and Rh. [6] Considering the high potential applied during OER, noble-metal oxides such as IrO 2 and RuO 2 are widely chosen as the state-of-the-art electrocatalysts. Nevertheless, RuO 2 is highly unstable in both acidic and alkaline electrolytes under high anodic potential. [7] Although IrO 2 Oxygen evolution reaction (OER) is an important half-reaction involved in many electrochemical applications, such as water splitting and rechargeable metal-air batteries. However, the sluggish kinetics of its four-electron transfer process becomes a bottleneck to the performance enhancement. Thus, rational design of electrocatalysts for OER based on thorough understanding of mechanisms and structure-activity relationship is of vital significance. This review begins with the introduction of OER mechanisms which include conventional adsorbate evolution mechanism and lattice-oxygen-mediated...

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Section: Transition Metal‐based Oer Electrocatalystsmentioning

confidence: 99%

Advanced Transition Metal‐Based OER Electrocatalysts: Current Status, Opportunities, and Challenges

Zhang

Zou

2021

Small

432

273

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“…It further signifies the first direct exfoliation of Hematene with sonication method within a short period. We called it a fast process, as the time required for the formation of Hematene is 5 min, whereas in other studies it takes a long time (more than 20 hours) to exfoliate the sample [22,26,27] which finds an interesting aspect from the processing point of view, and it is first of its kind to the best of our knowledge.…”

Section: Hematene Fabrication and Its Morphological Study With Hrtemmentioning

confidence: 99%

“…There are two types of atomic layers observed. The inward layer and outer layers are repeating in ordered manners refer to the formation of a single layer Hematene sheet [22,27]. The FFT of the corresponding lattice fringes [ Figure 2J] also shows the formation of hexagonal spots corresponding to each atom constituting the Hematene crystallographic structure and its repeating in a similar pattern.…”

Section: Detail Atomic Structure Investigation Of Hematene Sheet Withmentioning

confidence: 99%

“…Not only magnetism, but Hematene also find suitable application in the biomedical sector and associated energy research with the development of it for glucose sensing application with its electrocatalytic application followed by the development of a biofuel cell operated by glucose [26]. For the oxygen evolution electrocatalysis study, recently defect enriched Hematene is shown a current density of 10 mA/cm 2 at 0.250 V overpotential [27]. The energy storage outlook of this material is recently taken into consideration and is published elsewhere [28].…”

Section: Introductionmentioning

confidence: 99%

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Fast Sonochemical Exfoliation of Hematene type Sheets and Flakes from Hematite Nanoarchitectures Shows Enhanced Photocurrent Density

Bora

2021

Preprint

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<p><a>Here, we describe the exfoliation of 2D Hematene single layer from a Hematite nanoparticle-based nanoarchitectures obtained by a water-mediated synthesis route with the ultrasonication method in a brief period which is 5 min. The Hematene obtained shows the fine structure of honeycomb lattice resembling the Hematite hexagonal crystallographic pattern. Here, we found that the ultrasonicated Hematite film with Hematene flakes shows enhanced current density than the pristine Hematite film which can be extended further to increase the efficiency of well-performing or champion photoanode for the artificial photosynthesis application. Besides this, a new photocurrent transient spike is obtained, which we ascribed as the generation of the sub-surface state by Hematene flakes. Followed by this, we have also deciphered a qualitative predictive mechanism for the fast exfoliation of Hematene in which surface energies and hydroxylation of crystal facets are proposed to be the factor responsible for the quick exfoliation process. </a></p>

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“…Whether these materials possess any characteristics for photoelectrochemical functionality, we have further studied its detailed structural, topological, morphological, optical and surface composition investigation with advanced microscopy as well as spectroscopic and diffraction tools. manners refer to the formation of a single layer Hematene sheet [22,27].…”

Section: Sonochemical Exfoliation Of Hematene Sheets and Flakesmentioning

confidence: 99%

Fast Sonochemical Exfoliation of Hematene type Sheets and Flakes from Hematite Nanoarchitectures Shows Enhanced Photocurrent Density

Agarwal

Bora

2021

Preprint

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Revealing the defect-dominated oxygen evolution activity of hematene

Abstract: Oxygen electrocatalysis is vital for advanced energy technologies, but inordinate challenges remain due to the lack of highly active earth-abundant catalysts.

Cited by 63 publications

References 52 publications

Advanced Transition Metal‐Based OER Electrocatalysts: Current Status, Opportunities, and Challenges

Advanced Transition Metal‐Based OER Electrocatalysts: Current Status, Opportunities, and Challenges

Fast Sonochemical Exfoliation of Hematene type Sheets and Flakes from Hematite Nanoarchitectures Shows Enhanced Photocurrent Density

Fast Sonochemical Exfoliation of Hematene type Sheets and Flakes from Hematite Nanoarchitectures Shows Enhanced Photocurrent Density

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