Surface engineering by a novel electrochemical activation method for the synthesis of Co3+ enriched Co(OH)2/CoOOH heterostructure for water oxidation

Liu, Lu; Ou, Yingqing; Gao, Di; Yang, Lin; Dong, Hongmei; Xiao, Peng; Zhang, Yunhuai

doi:10.1016/j.jpowsour.2018.06.030

Cited by 58 publications

(34 citation statements)

References 51 publications

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“…The Fourier transform infrared spectroscopy (FTIR) as shown in Figure c shows that two distinct bands at 570 and 662 cm –1 are related to the Co–O 2– complex of Co 3 O 4 . In comparison with the p-Co 3 O 4 NSs, a new peak at 1632 cm –1 appears in the p-Co 3 O 4 NSs after the OER measurement, which is characteristic of the Co–O double band in the structure of CoOOH, further confirming the formation of Co 3+ (OOH*) during the OER reaction. The results of XPS and FTIR illustrate that Co 3+ is the major active site to adsorb OH* and O* in the Co 3 O 4 rather than Co 2+ during the OER process, which will be further demonstrated in the DFT calculations.…”

Section: Results and Discussionmentioning

confidence: 62%

Hydrazine Hydrate Induced Two-Dimensional Porous Co³⁺ Enriched Co₃O₄ Nanosheets for Enhanced Water Oxidation Catalysis

Chen

Tan

Zhang

et al. 2020

ACS Sustainable Chem. Eng.

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Herein, a hydrazine hydrate (N 2 H 4 ) induced sacrificial template method is reported for controlled synthesis of 2D porous Co 3 O 4 nanosheets (p-Co 3 O 4 NSs) with adjustable thickness and abundant hierarchical pore structure. The introduction of N 2 H 4 modulates the density of Co 2+ anchored on the surface of GO by adjusting the number of oxygen functional groups for Co 2+ /GO composites and then controls the thickness and electronic valence of Co 3 O 4 nanosheets during subsequent pyrolysis in air. As a result, the optimized 2D p-Co 3 O 4 NSs have ultrathin thickness, abundant hierarchical porous structure, and a high Co 3+ /Co 2+ ratio. As expected, it exhibits excellent OER catalytic performance in 1 M KOH solutions, affording a lower overpotential of 1.50 V at 10.0 mA cm −2 and robust stability compared to pristine Co 3 O 4 and RuO 2 as a benchmark. The outstanding OER catalytic activity is ascribed to its N 2 H 4 induced ultrathin 2D structure with abundant hierarchical pores and a high Co 3+ /Co 2+ ratio. The density functional theory (DFT) calculations reveal that the ultrathin layer Co 3 O 4 nanosheets with a high ratio of Co 3+ /Co 2+ enhance the OER activity through promoting the dissociation of water to OH* and accelerating kinetics of OER in alkaline media.

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Section: Results and Discussionmentioning

confidence: 62%

Hydrazine Hydrate Induced Two-Dimensional Porous Co³⁺ Enriched Co₃O₄ Nanosheets for Enhanced Water Oxidation Catalysis

Chen

Tan

Zhang

et al. 2020

ACS Sustainable Chem. Eng.

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“…1 (a) shows the XRD pattern of the sample, in which all of the refraction peaks can be indexed to a rhombohedral structure with space group R-3 m. All the diffraction peaks agree with those of β-CoOOH form (JCPDS Card No. 07-0169) [28][29][30][31] , Compared with CoOOH-650, the main diffraction peak width of CoOOH-750 is slightly narrower, indicating that CoOOH-750 has a larger size, and also illustrating that the temperature can affect the morphology size. However, CoOOH-850 at the (003) surface exhibits a large change, while the other surfaces exhibit little changes, indicating that the particle size might grow at the (003) face.…”

Section: Resultsmentioning

confidence: 96%

Molten salt-assisted synthesis of bulk CoOOH as a water oxidation catalyst

Song

Bao

Lin

et al. 2020

Journal of Energy Chemistry

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“…This may be due to the fact that the α‐Co(OH) 2 phase is a metastable phase and will easily transform into a stable β phase under alkaline conditions. [ 43,44 ] With increasing potential, the peak at 602 cm −1 shifted slightly to ≈596 cm −1 . At potentials of 0.12 V and above, the position of the 501 cm −1 peak remained unchanged.…”

Section: Resultsmentioning

confidence: 99%

An Unveiled Electrocatalysis Essence of NiCo Hydroxides through in Situ Raman Spectroscopy for Urea Oxidation

Zhang

et al. 2022

Energy Tech

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The electrochemical urea oxidation reaction (UOR) is the performance‐limiting half reaction of urea electrolysis for producing renewable hydrogen energy. Nevertheless, the essence of electrode function mechanism of catalysts remains unclear. Therefore, design and optimization of catalysts are restricted. Herein, an in situ Raman spectroscopy method is employed to directly measure the electrode properties of the NiCo double hydroxides (NiCo DHs) under working conditions. Given definitely evidence, the evolution process of in situ Raman spectra shows that the Ni element is converted to NiOOH under UOR potentials, while the Co dopant is converted to CoOOH and further to higher‐valence CoO2 species. Obviously, the catalytically active phase toward UOR is really a complex NiOOH–CoOOH–CoO2 phase. Accurately matched spectral wavenumbers and electrochemical measurements of the catalytic electrodes explicitly reveal that the addition of Co assuredly reduces the onset potential for electroactive NiOOH formation. The Raman results also indicate effects of the NiO bond elongation and increased disorder caused by Co doping. Herein, an important understanding and new mechanistic perspectives for the electrode reaction process of UOR with NiCo binary catalysts are provided.

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Surface engineering by a novel electrochemical activation method for the synthesis of Co3+ enriched Co(OH)2/CoOOH heterostructure for water oxidation

Cited by 58 publications

References 51 publications

Hydrazine Hydrate Induced Two-Dimensional Porous Co³⁺ Enriched Co₃O₄ Nanosheets for Enhanced Water Oxidation Catalysis

Hydrazine Hydrate Induced Two-Dimensional Porous Co³⁺ Enriched Co₃O₄ Nanosheets for Enhanced Water Oxidation Catalysis

Molten salt-assisted synthesis of bulk CoOOH as a water oxidation catalyst

An Unveiled Electrocatalysis Essence of NiCo Hydroxides through in Situ Raman Spectroscopy for Urea Oxidation

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Surface engineering by a novel electrochemical activation method for the synthesis of Co3+ enriched Co(OH)2/CoOOH heterostructure for water oxidation

Cited by 58 publications

References 51 publications

Hydrazine Hydrate Induced Two-Dimensional Porous Co3+ Enriched Co3O4 Nanosheets for Enhanced Water Oxidation Catalysis

Hydrazine Hydrate Induced Two-Dimensional Porous Co3+ Enriched Co3O4 Nanosheets for Enhanced Water Oxidation Catalysis

Molten salt-assisted synthesis of bulk CoOOH as a water oxidation catalyst

An Unveiled Electrocatalysis Essence of NiCo Hydroxides through in Situ Raman Spectroscopy for Urea Oxidation

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Hydrazine Hydrate Induced Two-Dimensional Porous Co³⁺ Enriched Co₃O₄ Nanosheets for Enhanced Water Oxidation Catalysis

Hydrazine Hydrate Induced Two-Dimensional Porous Co³⁺ Enriched Co₃O₄ Nanosheets for Enhanced Water Oxidation Catalysis