Electrochemically activated cobalt nickel sulfide for an efficient oxygen evolution reaction: partial amorphization and phase control

Hong, Yu; Mhin, Sungwook; Kim, Kang Min; Han, Won Sik; Choi, Heechae; Ali, Ghulam; Chung, Kyung Yoon; Lee, Ho Jun; Moon, Seung Il; Dutta, Soumen; Sun, Seho; Jung, Yeon Gil; Song, Taeseup; Han, Houde

doi:10.1039/c8ta10142f

Cited by 88 publications

(43 citation statements)

References 56 publications

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“…[ 9,10 ] Transition metal compounds, specifically, those containing Co, Ni, or Fe along with non‐metals such as O, N, S, Se, and P, are promising OER catalysts capable of outperforming benchmark IrO 2 and RuO 2 catalysts in alkaline solution. [ 11–15 ]…”

Section: Introductionmentioning

confidence: 99%

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

Han

Paik

Ham

et al. 2020

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simplicity, and absence of greenhouse gases. [5-8] However, the practical application of this process is limited by a kinetic bottleneck due to the thermodynamically unfavorable nature of the oxygen evolution reaction (OER; ΔH 0 /G 0 = 237 kJ mol −1) and its sluggish kinetics. [9,10] Transition metal compounds, specifically, those containing Co, Ni, or Fe along with non-metals such as O, N, S, Se, and P, are promising OER catalysts capable of outperforming benchmark IrO 2 and RuO 2 catalysts in alkaline solution. [11-15] Among the different transition metalbased hybrids, those containing Co exhibit the highest OER catalytic activity in alkaline media owing to the favorable adsorption/desorption energies of hydroxyl ions or water molecules. [16-18] Feng et al. recently developed highly efficient Co-based nanomaterials for OER in alkaline media through a facile synthetic route, which outperforms novel metal based catalysts such as RuO 2. [19-21] Hence, much effort has been made to further increase the OER catalytic activity of Co-based hybrids via various strategies such as the incorporation of N dopants to form CoN bonds. [18,21] To be specific, pyridinic N-Co bonding facilitates electron storage and transfer between oxygen-containing adsorbed intermediates (e.g., O*, OH*, OO*, and OOH*) and the active sites, thus boosting the electrocatalytic OER performance of Co-based hybrids. Furthermore, the formation of a well-defined hetero interface between highly conductive carbon materials and catalyst nanoparticles can lead to high stability and high activity for alkaline water oxidation. [9,22] In view of the high affinity of N to transition metals, strong physicochemical contacts between metallic Co species and N (especially pyridinic-N) doped carbon supports can effectively enhance interfacial charge transfer to result in synergetic effects for enhanced oxygen electrochemistry. [16,23] Pyridinic-N is an electron-withdrawing species due to the lone pair electrons involved in the resonance, and thus tends to accept electrons from the next C atoms. This results in a number of advantageous factors for enhancing alkaline OER activity; i) favors the adsorption of OER intermediates such a s OH− or OOH− which are typical rate-determining steps (RDS) for alkaline water oxidation or ii) the electron-deficient carbon Transition metal (TM)-based carbon hybrids have numerous applications in the field of regenerative electrochemical energy. The synergetic effects of high conductivity of carbon supports and abundant catalytic active sites in TMs make these hybrids promising oxygen evolution reaction (OER) electrocatalysts. However, strategies for modulating the catalytic active species in the above hybrids are limited despite being highly sought after. Furthermore, the exact roles of chemical species in the hybrids (e.g., N, C, or TM) mainly responsible for this high OER performance remain unknown. Herein, an innovative approach based on atomic layer deposition is developed to tune the true active species in Co nanoparticle/N-doped...

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Section: Introductionmentioning

confidence: 99%

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

Han

Paik

Ham

et al. 2020

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“…In contrast, Kolyagin and Kornienko, who investigated the wetting of porous hydrophobized gas diffusion electrodes, calculated the double‐layer capacitance related to the total surface area wetted by electrolyte from the slopes of the tangents to the data obtained at low scan‐rates leaving out the higher potential scan‐rates where the plot deviates from linear behaviour [92] . Other authors, in turn, simply assume a linear relationship and calculate the double‐layer capacitance from the line of best fit [93–95] . However, the authors ascribed deviation of specific capacitance from linearity with increasing potential scan‐rate to be due to i) an easily accessible outer surface area, C outer , that can be readily charged particularly at high potential scan‐rates and ii) an inner surface area, C inner , created by the pore network within the catalyst particle structure, which is less accessible due to mass transfer/diffusion limitation of ions resulting in less charge stored and lower double‐layer capacitance values, respectively [90,91,96] .…”

Section: Resultsmentioning

confidence: 99%

“…[92] Other authors, in turn, simply assume a linear relationship and calculate the double-layer capacitance from the line of best fit. [93][94][95] However, the authors ascribed deviation of specific capacitance from linearity with increasing potential scan-rate to be due to i) an easily accessible outer surface area, C outer , that can be readily charged particularly at high potential scan-rates and ii) an inner surface area, C inner , created by the pore network within the catalyst particle structure, which is less accessible due to mass transfer/diffusion limitation of ions resulting in less charge stored and lower double-layer capacitance values, respectively. [90,91,96] Therefore, capacitance at low potential scan-rates is representative of the total surface capacitance, i. e., the capacitance due to inner and outer surface area, whereas the capacitance at higher potential scan-rates corresponds to the charge of easily accessible outer surface area.…”

Section: Orr Activity and Stability Evaluationmentioning

confidence: 99%

Bifunctional α‐MnO₂ and Co₃O₄ Catalyst for Oxygen Electrocatalysis in Alkaline Solution

et al. 2020

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This work is dedicated to Prof. Monika Willert-Porada. We kindly would like to thank her for her contribution to the project and her support. Low cost and abundant catalysts demonstrating high activity and stability towards the oxygen reactions, i. e., the oxygen reduction (ORR) and oxygen evolution reaction (OER), are crucial for the development of electrically rechargeable zinc-air batteries. Herein, the facile synthesis and systematic characterisation of two highly active and stable oxygen electrocatalysts, i. e., high surface area α-MnO 2 microspheres and nanoparticulate Co 3 O 4 , are reported. α-MnO 2 exhibits low half-wave potential and potential of À 0.197 and À 0.226 V (vs. Ag/AgCl) at À 3 mA cm À 2 , respectively, that are only marginally higher compared to commercial Pt/C (E 1/2 = À 0.161 V, E j =-3 = À 0.171 V) for ORR. Meanwhile, Co 3 O 4 needs a potential of 0.601 V (vs. Ag/ AgCl) to drive 10 mA cm À 2 being competitive to commercial Ir/C (E j = 10 = 0.60 V) for OER. In order to create a bifunctional catalyst, two approaches were pursued: i) Co 3 O 4 nanoparticles were homogeneously grown on the surface of α-MnO 2 microspheres yielding a radial hybrid composite catalyst material in the form of a core (α-MnO 2) shell (Co 3 O 4) structure and ii), much simpler, individual α-MnO 2 microspheres and Co 3 O 4 nanoparticles were physically mixed in a powder blend. The powder blend demonstrates superior overall bifunctional catalytic properties such that the individual catalysts still dominate their respective oxygen reaction and, due to synergistic interactions between both catalysts, an improved ORR activity could be achieved.

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“…The resulting phase boundaries will significantly harmonize the respective advantages of amorphous and crystalline phases. However, the study of such catalysts has rarely been reported . Iron is relatively biocompatible and often serves as a central element in biological systems .…”

Section: Figurementioning

confidence: 99%

Favorable Amorphous−Crystalline Iron Oxyhydroxide Phase Boundaries for Boosted Alkaline Water Oxidation

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Interface engineering has proven an effective strategy for designing high-performance water-oxidation catalysts. Interface construction combining the respective advantages of amorphous and crystalline phases, especially embedding amorphous phases in crystalline lattices, has been the focus of intensive research. This study concerns the construction of an amorphousÀ crystalline FeOOH phase boundary (aÀ c-FeOOH) by structural evolution of iron oxyhydroxide-isolated Fe(OH) 3 precursors from one-step hydrothermal synthesis. aÀ c-FeOOH demonstrates superb electrocatalytic activity for the oxygen evolution reaction (OER) with overpotential of 330 mV to drive a current density of 300 mA cm À 2 in 1.0 m KOH, which is among the best OER catalysts and much better than the pristine amorphous or crystalline FeOOH alone. Density functional theory calculations reveal that the high-density aÀ c phase boundaries play a critical role in determining high OER activity.

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Electrochemically activated cobalt nickel sulfide for an efficient oxygen evolution reaction: partial amorphization and phase control

Abstract: It has recently been demonstrated that the OER activity of transition metal sulfides (TMSs) could be enhanced by the introduction of a thin amorphous layer on a pristine surface.

Cited by 88 publications

References 56 publications

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

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

Bifunctional α‐MnO₂ and Co₃O₄ Catalyst for Oxygen Electrocatalysis in Alkaline Solution

Favorable Amorphous−Crystalline Iron Oxyhydroxide Phase Boundaries for Boosted Alkaline Water Oxidation

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Electrochemically activated cobalt nickel sulfide for an efficient oxygen evolution reaction: partial amorphization and phase control

Abstract: It has recently been demonstrated that the OER activity of transition metal sulfides (TMSs) could be enhanced by the introduction of a thin amorphous layer on a pristine surface.

Cited by 88 publications

References 56 publications

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

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

Bifunctional α‐MnO2 and Co3O4 Catalyst for Oxygen Electrocatalysis in Alkaline Solution

Favorable Amorphous−Crystalline Iron Oxyhydroxide Phase Boundaries for Boosted Alkaline Water Oxidation

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Bifunctional α‐MnO₂ and Co₃O₄ Catalyst for Oxygen Electrocatalysis in Alkaline Solution