Bimetallic Co2Mo3O8 suboxides coupled with conductive cobalt nanowires for efficient and durable hydrogen evolution in alkaline electrolyte

Ou, Yingqing; Tian, Wei Quan; Liu, Lu; Zhang, Yunhuai; Xiao, Peng

doi:10.1039/c7ta11401j

Cited by 69 publications

(67 citation statements)

References 47 publications

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“…SEM, TEM (transmission electron microscope), XRD, and Raman were employed to confirm the composition of TMOs@MXene. As shown in Figure b–d, the obvious layered structure was attributed to MXene shell, while the lattice fringes of 0.246 and 0.201 nm can be pointed to the (111) plane of CoO and (203) plane of Co 2 Mo 3 O 8 , respectively . The element mapping results shown in Figure e further demonstrated the uniform distribution of Ti, C, Co, and Mo within the hollow framework.…”

Section: Resultsmentioning

confidence: 66%

Electrostatically Assembling 2D Nanosheets of MXene and MOF‐Derivatives into 3D Hollow Frameworks for Enhanced Lithium Storage

Zhao

Hui

et al. 2019

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As an essential member of 2D materials, MXene (e.g., Ti3C2Tx) is highly preferred for energy storage owing to a high surface‐to‐volume ratio, shortened ion diffusion pathway, superior electronic conductivity, and neglectable volume change, which are beneficial for electrochemical kinetics. However, the low theoretical capacitance and restacking issues of MXene severely limit its practical application in lithium‐ion batteries (LIBs). Herein, a facile and controllable method is developed to engineer 2D nanosheets of negatively charged MXene and positively charged layered double hydroxides derived from ZIF‐67 polyhedrons into 3D hollow frameworks via electrostatic self‐assembling. After thermal annealing, transition metal oxides (TMOs)@MXene (CoO/Co2Mo3O8@MXene) hollow frameworks are obtained and used as anode materials for LIBs. CoO/Co2Mo3O8 nanosheets prevent MXene from aggregation and contribute remarkable lithium storage capacity, while MXene nanosheets provide a 3D conductive network and mechanical robustness to facilitate rapid charge transfer at the interface, and accommodate the volume expansion of the internal CoO/Co2Mo3O8. Such hollow frameworks present a high reversible capacity of 947.4 mAh g−1 at 0.1 A g−1, an impressive rate behavior with 435.8 mAh g−1 retained at 5 A g−1, and good stability over 1200 cycles (545 mAh g−1 at 2 A g−1).

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Section: Resultsmentioning

confidence: 66%

Electrostatically Assembling 2D Nanosheets of MXene and MOF‐Derivatives into 3D Hollow Frameworks for Enhanced Lithium Storage

Zhao

Hui

et al. 2019

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156

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“…In order to obtain Cu/Co hybrid oxides, dehydration process was necessary ,. Further, partial reduction of oxides into low‐valence metal oxides or even zero‐valence alloy was helpful to lessen the electrical resistance or to increase the electrical conductivity, which is expected to lower the energy consumption in the catalytic process ,. Therefore, in the process of partial reduction, 5 % (v/v) hydrogen was added.…”

Section: Resultsmentioning

confidence: 95%

“…Therefore, in the process of partial reduction, 5 % (v/v) hydrogen was added. In many previous reports, the temperature of hydrogen reduction reaction often was set excess 450 °C ,. Generally, elevated temperature favors in the dehydration of hydroxides and the reduction reaction.…”

Section: Resultsmentioning

confidence: 95%

“…The Mo 3d spectrum of Mo‐doped Cu 2.5 CoO x (1.2 %) exhibited a spin orbit doublet located at 232.65 eV and 235.90 eV, representative of Mo 6+ 3d 5/2 and Mo 6+ 3d 3/2 on the surface, respectively. In addition, two peaks at 232.17 eV and 235.39 eV was a typical feature of Mo 5+ . The peaks shifted upon the Mo content.…”

Section: Resultsmentioning

confidence: 99%

“…Up to now, a series of non‐noble electrocatalysts, like earth‐abundantly transition metal chalcogenides, oxides, carbide, nitrides,, borides and phosphides as well as their hybrids, have attracted more attention because of their low price and excellent performance. Among them, transition metal oxides (TMOs, such as CoOx, NiOx, FeOx) have sparked considerable attention owing to their rich redox chemistry and simple preparation methods .…”

Section: Introductionmentioning

confidence: 99%

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Mo‐Doped Cu/Co Hybrid Oxide Nanoarrays: An Enhanced Electrocatalytic Performance for the Hydrogen Evolution Reaction

et al. 2019

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To achieve a cost‐effective and performance‐enhanced electrocatalyst for the hydrogen evolution reaction (HER), Mo‐doped Cu/Co hybrid oxides were prepared through the processes of hydrothermal chemistry and dehydration/reduction. Hybrid structures consisting of a polycrystalline hybrid crystal structure and an amorphous structure, and hybrid constituents including at least Cu, Cu2O, CuO, CoO, CuCoO2, and Cu2CoO3 were identified and characterized by using SEM, HR‐TEM, XPS as well as electrochemical analysis. Interestingly, no information of the doped Mo appeared in the XRD patterns. The reasonable deduction is that Mo might be confined in the amorphous area. The highly developed interface, enhanced conductivity, larger active surface area, abundant oxygen vacancies, and redistribution of electrons among these elements resulted in the significantly enhanced electrocatalytic activity. The optimized Mo‐doped hybrid Cu/Co oxide exhibited catalytic activity with an overpotential of 88 mV to obtain a current density of 10 mA cm−2 in alkaline electrolyte with scarce loss of the initial catalyst activity for 28 h and over 5000 cycles. This work may provide a channel to enhance the performance in the HER.

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Purification of Residual Ni and Co Hydroxides from Fe‐Free Alkaline Electrolyte for Electrocatalysis Studies

et al. 2022

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It is critical to control Fe impurity concentrations in oxygen‐evolution‐reaction electrocatalysis experiments so that unambiguous assignments of activity and mechanistic details can be made. An established method to prepare Fe‐free KOH electrolyte is by using particulate Ni(OH)2 or Co(OH)2 as absorbents to remove the Fe from KOH or other neutral‐to‐alkaline electrolytes. However, this method yields residual Ni or Co species in the electrolyte which can be redeposited on the working electrode. Thus, current methods of Fe removal could convolute studies of OER. In this work, we compared two different methods, continuous electrolysis and nano‐filtration, to remove the Ni and/or Co species from Fe‐free alkaline electrolyte. We found the best approach is to pass the Fe‐free electrolyte through a hydrophilic 0.1 μm polyethersulfone filter which decreases the Ni species concentration in 1 M KOH to single ppb levels. This result suggests the remaining Ni or Co species are primarily particulate in nature, consistent with their small solubility as ions. In comparison, extended pre‐electrolysis of the electrolyte removed only a portion of the Ni/Co.

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Bimetallic Co₂Mo₃O₈ suboxides coupled with conductive cobalt nanowires for efficient and durable hydrogen evolution in alkaline electrolyte

Abstract: Development of highly active and robust earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) is of great significance for the broad utilization of alkaline electrolyzers.

Cited by 69 publications

References 47 publications

Electrostatically Assembling 2D Nanosheets of MXene and MOF‐Derivatives into 3D Hollow Frameworks for Enhanced Lithium Storage

Electrostatically Assembling 2D Nanosheets of MXene and MOF‐Derivatives into 3D Hollow Frameworks for Enhanced Lithium Storage

Mo‐Doped Cu/Co Hybrid Oxide Nanoarrays: An Enhanced Electrocatalytic Performance for the Hydrogen Evolution Reaction

Purification of Residual Ni and Co Hydroxides from Fe‐Free Alkaline Electrolyte for Electrocatalysis Studies

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