Novel fluorine-doped cobalt molybdate nanosheets with enriched oxygen-vacancies for improved oxygen evolution reaction activity

Xie, Weiwei; Huang, Jianhao; Huang, Liangbin; Geng, Shipeng; Song, Shuqin; Tsiakaras, Panagiotis; Wang, Yi

doi:10.1016/j.apcatb.2021.120871

Cited by 98 publications

(23 citation statements)

References 47 publications

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“…To furtherly confirm the formation of CoMoO 4 @γ-FeOOH, Raman tests were conducted. As shown in Figure S4, the bands located at 326, 846, and 935 cm −1 for the Co-O-Mo, O-Mo-O, and Mo-O vibrations, respectively, could be found in both the CoMoO 4 and CoMoO 4 @γ-FeOOH nanosheets [29], while the Raman band located at 230, which could likely be ascribed to Fe-O vibrations, could be found in both the γ-FeOOH and CoMoO 4 @γ-FeOOH nanosheets [18]. This spectra information indicates the co-existence of CoMoO 4 and γ-FeOOH in the CoMoO 4 @γ-FeOOH nanosheets.…”

Section: Resultsmentioning

confidence: 91%

Construction of Core–Shell CoMoO4@γ-FeOOH Nanosheets for Efficient Oxygen Evolution Reaction

Song

Sheng

et al. 2022

Nanomaterials

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The oxygen evolution reaction (OER) occurs at the anode in numerous electrochemical reactions and plays an important role due to the nature of proton-coupled electron transfer. However, the high voltage requirement and low stability of the OER dramatically limits the total energy converting efficiency. Recently, electrocatalysts based on multi-metal oxyhydroxides have been reported as excellent substitutes for commercial noble metal catalysts due to their outstanding OER activities. However, normal synthesis routes lead to either the encapsulation of excessively active sites or aggregation during the electrolysis. To this end, we design a novel core–shell structure integrating CoMoO4 as support frameworks covered with two-dimensional γ-FeOOH nanosheets on the surface. By involving CoMoO4, the electrochemically active surface area is significantly enhanced. Additionally, Co atoms immerge into the γ-FeOOH nanosheet, tuning its electronic structure and providing additional active sites. More importantly, the catalysts exhibit excellent OER catalytic performance, reducing overpotentials to merely 243.1 mV a versus 10 mA cm−2. The current strategy contributes to advancing the frontiers of new types of OER electrocatalysts by applying a proper support as a multi-functional platform.

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Section: Resultsmentioning

confidence: 91%

Construction of Core–Shell CoMoO4@γ-FeOOH Nanosheets for Efficient Oxygen Evolution Reaction

Song

Sheng

et al. 2022

Nanomaterials

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“…All electrochemical experiments were performed on a CHI 760E (Shanghai Chenhua, China) potentiostat in 1 M KOH with a Pt plate as a counter electrode and a Hg/HgO/KOH (1 M) electrode as a reference electrode. All potentials reported in this work were converted to the reversible hydrogen electrode (RHE) reference scale according to the equation E RHE = E Hg/HgO + 0.059 × pH + 0.098 V. 61 Cyclic voltammetry (CV) measurements were performed with a scan rate of 50 mV s −1 . Moreover, the linear sweep voltammetry (LSV) curves were recorded at a 5 mV s −1 scan rate.…”

Section: Methodsmentioning

confidence: 99%

Enhanced Alkaline Oxygen Evolution Using Spin Polarization and Magnetic Heating Effects under an AC Magnetic Field

Zheng

Wang

Xie

et al. 2022

ACS Appl. Mater. Interfaces

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Renewable electricity from splitting water to produce hydrogen is a favorable technology to achieve carbon neutrality, but slow anodic oxygen evolution reaction (OER) kinetics limits its large-scale commercialization. Electron spin polarization and increasing the reaction temperature are considered as potential ways to promote alkaline OER. Here, it is reported that in the alkaline OER process under an AC magnetic field, a ferromagnetic ordered electrocatalyst can simultaneously act as a heater and a spin polarizer to achieve significant OER enhancement at a low current density. Moreover, its effect obviously precedes antiferromagnetic, ferrimagnetic, and diamagnetic electrocatalysts. In particular, the noncorrected overpotential of the ferromagnetic electrocatalyst Co at 10 mA cm −2 is reduced by a maximum of 36.6% to 243 mV at 4.320 mT. It is found that the magnetic heating effect is immediate, and more importantly, it is localized and hardly affects the temperature of the entire electrolytic cell. In addition, the spin pinning effect established on the ferromagnetic/paramagnetic interface generated during the reconstruction of the ferromagnetic electrocatalyst expands the ferromagnetic order of the paramagnetic layer. Also, the introduction of an external magnetic field further increases the orderly arrangement of spins, thereby promoting OER. This work provides a reference for the design of high-performance OER electrocatalysts under a magnetic field.

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“…The calculated total and partial density of states (DOS) of the α-Fe 2 O 3 /NiOOH photoanode with and without oxygen vacancies are shown in Figures f and S25 and demonstrate that the hybridization between Fe 3d, Ni 4d, and O 2p orbitals facilitates the enhancement of electronic states near the Fermi level. The asymmetry of DOS leads to the formation of metallic characteristics, which enhances the capability of charge transfer during OER. − The creation of an oxygen vacancy leaves two electrons per missing oxygen atom. This increases the overall majority (i.e., electron) concentration and conductivity.…”

Section: Resultsmentioning

confidence: 99%

Reconstructing Oxygen Vacancies in the Bulk and Nickel Oxyhydroxide Overlayer to Promote the Hematite Photoanode for Photoelectrochemical Water Oxidation

Zhou

Wang

Liang

et al. 2022

ACS Appl. Energy Mater.

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Surface engineering, as an efficient strategy, can improve the photoelectrochemical water splitting (PEC-WS) performance for converting inexhaustible sunlight into clean hydrogen fuel. Oxyhydroxides and p–n heterojunctions have been demonstrated as efficient catalysts for the water oxidation reaction. In this work, to address the drawbacks of poor conductivity and sluggish oxidation kinetics of hematite, we introduce a p-type NiOOH overlayer as a surface catalyst onto n-type Sn-doping hematite (Sn@α-Fe2O3) photoanode. The oxygen vacancies (Ov) are reconstructed both in the bulk of Sn@α-Fe2O3 and the surface decoration layer of NiOOH via Ar plasma treatment, effectively reducing unavoidable defects introduced by the NiOOH overlayer. Compared with the original Sn@α-Fe2O3 photoanode, the Sn@α-Fe2O3/NiOOH–Ar photoanode exhibits a significant increase in photocurrent density (at 1.23 VRHE) of ∼3 times and a decrease in the onset potential of ∼200 mV. The performance improvement can be ascribed to the synergistic effect of the p–n junctions formed by NiOOH decoration and improved conductivity through oxygen vacancy reconstruction, which remarkably improves carrier separation in the bulk of α-Fe2O3 and suppresses carrier recombination on the photoanode surface. Moreover, the density functional theory (DFT) calculation proves that the real active sites are farther from (rather than near) the oxygen vacancies.

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Novel fluorine-doped cobalt molybdate nanosheets with enriched oxygen-vacancies for improved oxygen evolution reaction activity

Cited by 98 publications

References 47 publications

Construction of Core–Shell CoMoO4@γ-FeOOH Nanosheets for Efficient Oxygen Evolution Reaction

Construction of Core–Shell CoMoO4@γ-FeOOH Nanosheets for Efficient Oxygen Evolution Reaction

Enhanced Alkaline Oxygen Evolution Using Spin Polarization and Magnetic Heating Effects under an AC Magnetic Field

Reconstructing Oxygen Vacancies in the Bulk and Nickel Oxyhydroxide Overlayer to Promote the Hematite Photoanode for Photoelectrochemical Water Oxidation

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