Amorphous nickel tungstate films prepared by SILAR method for electrocatalytic oxygen evolution reaction

Malavekar, D.B.; Lokhande, Vaibhav C.; Patil, D.J.; Kale, Shital B.; Patil, Umakant M.; Ji, Taeksoo; Lokhande, C. D.

doi:10.1016/j.jcis.2021.11.074

Cited by 22 publications

(11 citation statements)

References 35 publications

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“…In the very beginning, the addition of an equivalent amount of sodium salt of the oxyanion (Na 2 MoO 4 ·2H 2 O for NiMoO 4 and Na 2 WO 4 ·2H 2 O for NiWO 4 ) to the nickel(II) solution resulted in the formation of an amorphous NiXO 4 (where X = Mo and W) precipitate, which then transformed into nanostructured materials under hydrothermal conditions (Figure S1). Isolated NiXO 4 materials were then analyzed through powder X-ray diffraction (PXRD). Well-defined and sharp diffractions between a 2θ value of 20–80° corroborated the crystalline nature of both NiMoO 4 and NiWO 4 (Figure a).…”

Section: Resultsmentioning

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%

“…44 ■ RESULTS AND DISCUSSION (Figure S1). 45 Isolated NiXO 4 materials were then analyzed through powder X-ray diffraction (PXRD). Well-defined and sharp diffractions between a 2θ value of 20−80°corroborated the crystalline nature of both NiMoO 4 and NiWO 4 (Figure 1a).…”

Section: ■ Introductionmentioning

confidence: 99%

Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

2022

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“…As shown in Figure 5 b, the Ni 7 FeO x (OH) y @NCA exhibits the smallest Tafel slope of 72 mV·dec −1 , which is much better than those of the FeO x (OH) y @NCA (145 mV·dec −1 ), NiO x (OH) y @NCA (210 mV·dec −1 ), Ni 7 FeO x (OH) y @CA (112 mV·dec −1 ), RuO 2 (102 mV·dec −1 ), and Ni 7 FeO x (OH) y (126 mV·dec −1 ) that the optimal Ni 7 FeO x (OH) y @NCA has the fastest OER kinetics. To further investigate the electrocatalytic performance of NiFeO x (OH) y @NCA, we have performed cyclic voltammetric (CV) measurements to determine the double-layer capacitances (C dl ), which is considered an effective evaluation method of the electronic catalytic surface area (ECSA) [ 42 ]. The CV curves of the resulting electrocatalysts at varying scan rates are shown in Figure S4 .…”

Section: Resultsmentioning

confidence: 99%

Electronic Modulation of the 3D Architectured Ni/Fe Oxyhydroxide Anchored N-Doped Carbon Aerogel with Much Improved OER Activity

Hao

et al. 2023

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It remains a big challenge to develop non-precious metal catalysts for oxygen evolution reaction (OER) in energy storage and conversion systems. Herein, a facile and cost-effective strategy is employed to in situ prepare the Ni/Fe oxyhydroxide anchored on nitrogen-doped carbon aerogel (NiFeOx(OH)y@NCA) for OER electrocatalysis. The as-prepared electrocatalyst displays a typical aerogel porous structure composed of interconnected nanoparticles with a large BET specific surface area of 231.16 m2·g−1. In addition, the resulting NiFeOx(OH)y@NCA exhibits excellent OER performance with a low overpotential of 304 mV at 10 mA·cm−2, a small Tafel slope of 72 mV·dec−1, and excellent stability after 2000 CV cycles, which is superior to the commercial RuO2 catalyst. The much enhanced OER performance is mainly derived from the abundant active sites, the high electrical conductivity of the Ni/Fe oxyhydroxide, and the efficient electronic transfer of the NCA structure. Density functional theory (DFT) calculations reveal that the introduction of the NCA regulates the surface electronic structure of Ni/Fe oxyhydroxide and increases the binding energy of intermediates as indicated by the d-band center theory. This work provides a new method for the construction of advanced aerogel-based materials for energy conversion and storage.

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“…The polarization curves were measured at a scan rate of 1 mV s −1 in the potentials between +0.1 V and +0.75 versus Hg/HgO. The measured potentials were converted to the reversible hydrogen electrode (RHE) scale using the Nernst equation

E_{RHE} = E_{Hg / HgO} + 0.059 \times pH + E_{Hg / HgO}^{0}

where

E_{Hg / HgO}

is the potential measured versus Hg/HgO electrode,

E_{RHE}

is the calculated potential values versus RHE, and

E_{Hg / HgO}^{0}

is the redox potential of Hg/HgO electrode (0.140 V ± 0.001 V) at 298 K. The overpotential ( η ) was calculated from the polarization curve at a current density of 100 mA cm −2 using the following equation [ 18 ]

η_{@ 100} false(normalV false) = E_{RHE} false(normalV false) - 1.23 false(normalV false)

…”

Section: Methodsmentioning

confidence: 99%

“…where E Hg=HgO is the potential measured versus Hg/HgO electrode, E RHE is the calculated potential values versus RHE, and E 0 Hg=HgO is the redox potential of Hg/HgO electrode (0.140 V AE 0.001 V) at 298 K. The overpotential (η) was calculated from the polarization curve at a current density of 100 mA cm À2 using the following equation [18] η @100 ðVÞ ¼ E RHE ðVÞ À 1.23ðVÞ…”

Section: Electrochemical Characterizationsmentioning

confidence: 99%

Efficient Electrochemical Water Splitting Through Self‐Supported Copper Selenide Nanosheets on Cu Foil: Effect of Immersion Time

et al. 2023

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Transition metal selenides have been attracting enormous attention for electrocatalytic water oxidation. Herein, a self‐supported Cu3Se2@Cu electrocatalyst is prepared using the simple self‐growth method at different immersion times. The immersion time is critical in the conversion of Cu(OH)2 to Cu3Se2 as well as the modification of surface morphology. The growth of thin films is analyzed using a field emission scanning electron microscope and X‐ray photoelectron spectroscopy techniques. The electrochemical analysis shows that 230 and 351 mV of overpotential are required to reach a current density of 10 and 100 mA cm−2, respectively, for the oxygen evolution reaction (OER). The chronopotentiometry measurement over 50 h at a current density of 100 mA cm−2 shows excellent stability of the self‐grown electrocatalyst. This work may provide an effective and controlled strategy to convert Cu substrate to Cu3Se2 for efficient OER catalysts with the self‐growth method.

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Amorphous nickel tungstate films prepared by SILAR method for electrocatalytic oxygen evolution reaction

Cited by 22 publications

References 35 publications

Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

Electronic Modulation of the 3D Architectured Ni/Fe Oxyhydroxide Anchored N-Doped Carbon Aerogel with Much Improved OER Activity

Efficient Electrochemical Water Splitting Through Self‐Supported Copper Selenide Nanosheets on Cu Foil: Effect of Immersion Time

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Amorphous nickel tungstate films prepared by SILAR method for electrocatalytic oxygen evolution reaction

Cited by 22 publications

References 35 publications

Intrinsic Lability of NiMoO4to Excel the Oxygen Evolution Reaction

Intrinsic Lability of NiMoO4to Excel the Oxygen Evolution Reaction

Electronic Modulation of the 3D Architectured Ni/Fe Oxyhydroxide Anchored N-Doped Carbon Aerogel with Much Improved OER Activity

Efficient Electrochemical Water Splitting Through Self‐Supported Copper Selenide Nanosheets on Cu Foil: Effect of Immersion Time

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Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction

Intrinsic Lability of NiMoO₄to Excel the Oxygen Evolution Reaction