Enhancing the electrocatalytic activity of NiMoO4 through a post-phosphorization process for oxygen evolution reaction

Zhang, Shaoyang; She, Guangwei; Li, Shengyang; Qu, Fangmu; Mu, Lixuan; Shi, Wensheng

doi:10.1016/j.catcom.2019.105725

Cited by 15 publications

(11 citation statements)

References 28 publications

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“…In brief, NiMoO 4 is inherently a precatalyst and the structural transformation on the NF surface is as follows: NiMoO 4 into Ni(OH) 2 /NiO and finally into γ-NiOOH. ,,,, Surprisingly, some studies reported NiMoO 4 nanostructures on NF as a stable catalyst under OER conditions (Table S1). It may presumably be due to a lack of postcharacterization data or inadequate intention toward the detection of the active species. ,,,, However, it may also be true that NiO(OH) ED may not be the actual active species. NiO and/or Ni(OH) 2 may have possibly formed at the very early stage of the catalyst’s evolution and later on transformed to NiO(OH) ED .…”

Section: Resultsmentioning

confidence: 99%

“…It may presumably be due to a lack of postcharacterization data or inadequate intention toward the detection of the active species. 27,33,35,36,75 However, it may also be true that NiO(OH) ED may not be the actual active species. NiO and/or Ni(OH) 2 may have possibly formed at the very early stage of the catalyst's evolution and later on transformed to NiO(OH) ED .…”

Section: ■ Introductionmentioning

confidence: 99%

“… − Several synthetic strategies were adopted to prepare highly active NiMoO 4 . A reliable technique was the in situ growth of NiMoO 4 on nickel foam (NF). , The preparation of a heterojunction interface using NiMoO 4 also remained successful to produce a highly active anode for the OER. ,,− Doping of the Fe/Co/Mn atom into the NiMoO 4 nanostructure and/or postsynthetic phosphorization of NiMoO 4 were also proven to be effective in improving the OER performance. ,− Generation of oxygen vacancy in the NiMoO 4 nanostructure was also shown to improve the OER efficiency . The morphology of the NiMoO 4 nanostructure could also influence the OER activity. , In addition to these, the performance of NiMoO 4 as a cathodic material for the HER is also remarkable. ,− Despite the remarkable electrochemical performance of NiMoO 4 , the crucial role of molybdenum in electrocatalytic events is hardly explored well.…”

Section: Introductionmentioning

confidence: 99%

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Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

2022

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Nickel-based bimetallic oxides such as NiMoO 4 and NiWO 4 , when deposited on the electrode substrate, show remarkable activity toward the electrocatalytic oxygen evolution reaction (OER). The stability of such nanostructures is nevertheless speculative, and catalytically active species have been less explored. Herein, NiMoO 4 nanorods and NiWO 4 nanoparticles are prepared via a solvothermal route and deposited on nickel foam (NF) (NiMoO 4 / NF and NiWO 4 /NF). After ensuring the chemical and structural integrity of the catalysts on electrodes, an OER study has been performed in the alkaline medium. After a few cyclic voltammetry (CV) cycles within the potential window of 1.0−1.9 V (vs reversible hydrogen electrode (RHE)), ex situ Raman analysis of the electrodes infers the formation of NiO(OH) ED (ED: electrochemically derived) from NiMoO 4 precatalyst, while NiWO 4 remains stable. A controlled study, stirring of NiMoO 4 /NF in 1 M KOH without applied potential, confirms that NiMoO 4 hydrolyzes to the isolable NiO, which under a potential bias converts into NiO(OH) ED . Perhaps the more ionic character of the Ni− O−Mo bond in the NiMoO 4 compared to the Ni−O−W bond in NiWO 4 causes the transformation of NiMoO 4 into NiO(OH) ED .A comparison of the OER performance of electrochemically derived NiO(OH) ED , NiWO 4 , ex-situ-prepared Ni(OH) 2 , and NiO(OH) confirmed that in-situ-prepared NiO(OH) ED remained superior with a substantial potential of 238 (±6) mV at 20 mA cm −2 . The notable electrochemical performance of NiO(OH) ED can be attributed to its low Tafel slope value (26 mV dec −1 ), high double-layer capacitance (C dl , 1.21 mF cm −2 ), and a low charge-transfer resistance (R ct , 1.76 Ω). The NiO(OH) ED /NF can further be fabricated as a durable OER anode to deliver a high current density of 25−100 mA cm −2 . Post-characterization of the anode proves the structural integrity of NiO(OH) ED even after 12 h of chronoamperometry at 1.595 V (vs reversible hydrogen electrode (RHE)). The NiO(OH) ED /NF can be a compatible anode to construct an overall water splitting (OWS) electrolyzer that can operate at a cell potential of 1.64 V to reach a current density of 10 mA cm −2 . Similar to that on NF, NiMoO 4 deposited on iron foam (IF) and carbon cloth (CC) also electrochemically converts into NiO(OH) to perform a similar OER activity. This work understandably demonstrates monoclinic NiMoO 4 to be an inherently unstable electro(pre)catalyst, and its structural evolution to polycrystalline NiO(OH) ED succeeding the NiO phase is intrinsic to its superior activity.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

2022

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“…The working electrode was directly contacted with the PtSi or Pt x(x¼2,3) Si lm using a platinum electrode holder. 45 Both the samples were xed reaction area of 0.25 cm 2 with epoxy glue (Fig. S2a and c †).…”

Section: Electrochemical (Ec) and Photoelectrochemical (Pec) Measurem...mentioning

confidence: 99%

Electrochemical surface reconstructed Pt_x(x=2,3)Si/PtSi/p-Si photocathodes for achieving high efficiency in photoelectrochemical H₂ generation

Zhang

She

Xu³

et al. 2022

J. Mater. Chem. A

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“…These metal phosphide-based materials showed that during the electrochemical process, the oxyphosphides are oxidized to oxide or hydroxide species presenting active sites for OER [ 16 ]. Post-phosphorization treatment of NiMoO 4 (P-NMO) induced new active sites and resulted in improved performance for OER in alkaline solution so that OER onset potential at 5 mA·cm −2 (370 mV) was lower than that of IrO 2 (390 mV) along with lower Tafel slope (70.3 mV·dec −1 ) [ 31 ]. A three-dimensional self-operated Co-doped nickel selenide nanoflowers (3D Co–NiSe/NF) electrode showed low OER overpotential with Tafel slope of 111 mV·dec −1 in 1 M KOH [ 32 ].…”

Section: Introductionmentioning

confidence: 99%

Bimetallic Co-Based (CoM, M = Mo, Fe, Mn) Coatings for High-Efficiency Water Splitting

et al. 2020

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Bimetallic cobalt (Co)-based coatings were prepared by a facile, fast, and low-cost electroless deposition on a copper substrate (CoFe, CoMn, CoMo) and characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction analysis. Prepared coatings were thoroughly examined for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline solution (1 M potassium hydroxide, KOH) and their activity compared to that of Co and Ni coatings. All five coatings showed activity for both reactions, where CoMo and Co showed the highest activity for HER and OER, respectively. Namely, the highest HER current density was recorded at CoMo coating with low overpotential (61 mV) to reach a current density of 10 mA·cm−2. The highest OER current density was recorded at Co coating with a low Tafel slope of 60 mV·dec−1. Furthermore, these coatings proved to be stable under HER and OER polarization conditions.

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Enhancing the electrocatalytic activity of NiMoO4 through a post-phosphorization process for oxygen evolution reaction

Cited by 15 publications

References 28 publications

Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

Electrochemical surface reconstructed Pt_x(x=2,3)Si/PtSi/p-Si photocathodes for achieving high efficiency in photoelectrochemical H₂ generation

Bimetallic Co-Based (CoM, M = Mo, Fe, Mn) Coatings for High-Efficiency Water Splitting

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Enhancing the electrocatalytic activity of NiMoO4 through a post-phosphorization process for oxygen evolution reaction

Cited by 15 publications

References 28 publications

Intrinsic Lability of NiMoO4to Excel the Oxygen Evolution Reaction

Intrinsic Lability of NiMoO4to Excel the Oxygen Evolution Reaction

Electrochemical surface reconstructed Ptx(x=2,3)Si/PtSi/p-Si photocathodes for achieving high efficiency in photoelectrochemical H2 generation

Bimetallic Co-Based (CoM, M = Mo, Fe, Mn) Coatings for High-Efficiency Water Splitting

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Product

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About

Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

Electrochemical surface reconstructed Pt_x(x=2,3)Si/PtSi/p-Si photocathodes for achieving high efficiency in photoelectrochemical H₂ generation