Three dimensionally ordered mesoporous hydroxylated NixCo3−xO4 spinels for the oxygen evolution reaction: on the hydroxyl-induced surface restructuring effect

Abidat, Ismail; Morais, Cláudia; Comminges, Clément; Canaff, Christine; Rousseau, Julie; Guignard, Nadia; Napporn, Têko W.; Habrioux, Aurélien; Kokoh, K. Boniface

doi:10.1039/c7ta00185a

Cited by 57 publications

(54 citation statements)

References 57 publications

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“…It is known that after the surface restructuring the oxidation potential of surface Co II species is close to that required to oxidise Ni II surface species, located in the 1.3–1.4 V versus RHE range . The closeness of the two oxidation potentials depends on the Ni/Co atomic ratio . This explains why the shape of the M II /M III (where M=Co or Ni) redox transition is different for the NiCo 2 O 4 /RGO‐2_RGO sample, which shows two peaks centred at approximately 1.40 and 1.45 V versus RHE.…”

Section: Resultsmentioning

confidence: 66%

“…The electrochemical behaviour of all catalysts investigated was studied in alkaline medium; voltammograms are shown in Figure A. Unlike the Co 3 O 4 /RGO_GO catalyst, nickel cobaltites are subject to potential cycling‐induced surface restructuring . For these materials, only cyclic voltammograms recorded after 50 cycles are shown in Figure A.…”

Section: Resultsmentioning

confidence: 98%

“…Changes in terms of energy for this transition are due to changes in the chemical environment of Co atoms in the NiCo 2 O 4 structure. It is known that after the surface restructuring the oxidation potential of surface Co II species is close to that required to oxidise Ni II surface species, located in the 1.3–1.4 V versus RHE range . The closeness of the two oxidation potentials depends on the Ni/Co atomic ratio .…”

Section: Resultsmentioning

confidence: 98%

“…XPS spectra of Co 2p and Ni 2p regions for all samples are shown in Figure A and B, respectively. The Co 2p spectra can be decomposed using the previously reported linear combination approach . In this way, a linear combination of reference spectra obtained with commercial Co 3 O 4 (purple curve) and Co(OH) 2 (orange curve) materials can be used for the decomposition of Co 2p experimental spectra.…”

Section: Resultsmentioning

confidence: 99%

“…The area ratio values between the main peak and the satellite peak were 3.5, 3.9 and 3.5, respectively for NiCo 2 O 4 /RGO_GO, NiCo 2 O 4 /RGO‐1_RGO and NiCo 2 O 4 /RGO‐2_RGO catalysts, and only 2.1 for the commercial NiO sample. This result means that all materials contained high‐spin Ni 2+ cations located at octahedral sites in the spinel structure, and their number was especially high for NiCo 2 O 4 /RGO‐1_RGO material . Moreover Ni 2+ /Ni 3+ ratios obtained for NiCo 2 O 4 /RGO_GO, NiCo 2 O 4 /RGO‐1_RGO and NiCo 2 O 4 /RGO‐2_RGO materials, are 0.21, 0.25 and 0.25, respectively.…”

Section: Resultsmentioning

confidence: 99%

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Preparation and Electrochemical Properties of NiCo₂O₄ Nanospinels Supported on Graphene Derivatives as Earth‐Abundant Oxygen Bifunctional Catalysts

et al. 2018

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This work reports on the facile synthesis and characterisation of a non-precious-metal bifunctional catalyst for oxygen reduction and evolution reactions (ORR and OER). A few-layer reduced graphene oxide-supported NiCo O catalyst is prepared using a rapid and easy two-step method of synthesis. It consists of the solvothermal poyl(vinylpyrrolidone)-assisted assembly of metal complexes onto few-layer graphene followed by a calcination step aiming at converting metal complexes into the spinel phase. Using this synthesis approach, the most active material demonstrates an outstanding activity towards the OER and ORR, making it one of the best bifunctional catalysts of these reactions ever reported. This composite catalyst exhibits improved bifunctional behaviour with a low reversibility criterion of 746 mV. The ORR process follows a four-electron pathway and the hydroxyl selectivity is higher than those with pure reduced graphene oxide or NiCo O materials, showing the synergistic effect between the two phases. Moreover, the high activity of this composite catalyst is confirmed by comparing its performance with those obtained on other cobaltite catalysts prepared using a different synthesis method, or those obtained using a different graphene-based support.

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Section: Resultsmentioning

confidence: 66%

Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Preparation and Electrochemical Properties of NiCo₂O₄ Nanospinels Supported on Graphene Derivatives as Earth‐Abundant Oxygen Bifunctional Catalysts

et al. 2018

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Modulation of Brønsted and Lewis Acid Centers for Ni_xCo₃₋_xO₄ Spinel Catalysts: Towards Efficient Catalytic Conversion of Lignin

Xiao

Mei

et al. 2022

Adv Funct Materials

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Rational design and construction of catalysts with regulable activesites for selective cleavage of lignin to produce aromatic monomers remain challenging. Herein, the authors report a new strategy for tuning the active sites of tetrahedral centers (Lewis acid sites) and octahedral centers (Brønsted acid sites) in Ni x Co 3−x O 4 through tailoring the nonstoichiometric ratio of Ni and Co. The ratio of Ni and Co is experimentally optimized for the optimal acidic activity of catalytic cracking of lignin when x = 0.2. The Ni 0.2 Co 2.8 O 4 catalysts achieve an outstanding catalytic conversion (up to 81 wt%) for the lignin cleavage and excellent selective cleavage into aromatic monomers (up to 90.30 wt%), which is mainly attributed to the optimized electron rearrangement, adjustable active sites, and synergistic effect between these two active sites. This work provides a new concept to rationally design solid acid catalysts for the efficient conversion of lignin.

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Mastering Surface Reconstruction of Metastable Spinel Oxides for Better Water Oxidation

et al. 2019

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The development of efficient electrocatalysts that lower the overpotential of oxygen evolution reaction (OER) is of great importance in improving the overall efficiency of hydrogen fuel production by water electrolysis. [1] Commercially, precious metal oxides catalysts such as IrO 2 are used. [2] However, their elemental scarcity and high cost have triggered a search for cost-effective OER electrocatalysts such as 3d transition metal oxides. Among them, families such as the perovskite ABO 3 and the spinel AB 2 O 4 ones have attracted great attention due to their tunable structural/elemental properties allowed by A and B site cation substitution. [3,4] Perovskite ABO 3 oxides have a simple structure with rare-earth or alkaline earth element occupying cuboctahedral A-site while the B-site transition metal (TM) sites in an octahedral environment. [3] Spinel oxides, however, can be either normal or inverse structure depending on the relative occupancy of divalent and trivalent cations in the octahedral and Developing highly active electrocatalysts for oxygen evolution reaction (OER) is critical for the effectiveness of water splitting. Low-cost spinel oxides have attracted increasing interest as alternatives to noble metalbased OER catalysts. A rational design of spinel catalysts can be guided by studying the structural/elemental properties that determine the reaction mechanism and activity. Here, using density functional theory (DFT) calculations, it is found that the relative position of O p-band and M Oh (Co and Ni in octahedron) d-band center in ZnCo 2−x Ni x O 4 (x = 0-2) correlates with its stability as well as the possibility for lattice oxygen to participate in OER. Therefore, it is testified by synthesizing ZnCo 2−x Ni x O 4 spinel oxides, investigating their OER performance and surface evolution. Stable ZnCo 2−x Ni x O 4 (x = 0-0.4) follows adsorbate evolving mechanism under OER conditions. Lattice oxygen participates in the OER of metastable ZnCo 2−x Ni x O 4 (x = 0.6, 0.8) which gives rise to continuously formed oxyhydroxide as surface-active species and consequently enhances activity. ZnCo 1.2 Ni 0.8 O 4 exhibits performance superior to the benchmarked IrO 2 . This work illuminates the design of highly active metastable spinel electrocatalysts through the prediction of the reaction mechanism and OER activity by determining the relative positions of the O p-band and the M Oh d-band center.

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Three dimensionally ordered mesoporous hydroxylated Ni_xCo_3−xO₄ spinels for the oxygen evolution reaction: on the hydroxyl-induced surface restructuring effect

Abstract: Mesoporous nickel cobaltites synthesized using a nanocasting technique show high OER activity after surface modifications induced by potential cycling.

Cited by 57 publications

References 57 publications

Preparation and Electrochemical Properties of NiCo₂O₄ Nanospinels Supported on Graphene Derivatives as Earth‐Abundant Oxygen Bifunctional Catalysts

Preparation and Electrochemical Properties of NiCo₂O₄ Nanospinels Supported on Graphene Derivatives as Earth‐Abundant Oxygen Bifunctional Catalysts

Modulation of Brønsted and Lewis Acid Centers for Ni_xCo₃₋_xO₄ Spinel Catalysts: Towards Efficient Catalytic Conversion of Lignin

Mastering Surface Reconstruction of Metastable Spinel Oxides for Better Water Oxidation

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Three dimensionally ordered mesoporous hydroxylated NixCo3−xO4 spinels for the oxygen evolution reaction: on the hydroxyl-induced surface restructuring effect

Abstract: Mesoporous nickel cobaltites synthesized using a nanocasting technique show high OER activity after surface modifications induced by potential cycling.

Cited by 57 publications

References 57 publications

Preparation and Electrochemical Properties of NiCo2O4 Nanospinels Supported on Graphene Derivatives as Earth‐Abundant Oxygen Bifunctional Catalysts

Preparation and Electrochemical Properties of NiCo2O4 Nanospinels Supported on Graphene Derivatives as Earth‐Abundant Oxygen Bifunctional Catalysts

Modulation of Brønsted and Lewis Acid Centers for NixCo3−xO4 Spinel Catalysts: Towards Efficient Catalytic Conversion of Lignin

Mastering Surface Reconstruction of Metastable Spinel Oxides for Better Water Oxidation

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Product

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Three dimensionally ordered mesoporous hydroxylated Ni_xCo_3−xO₄ spinels for the oxygen evolution reaction: on the hydroxyl-induced surface restructuring effect

Preparation and Electrochemical Properties of NiCo₂O₄ Nanospinels Supported on Graphene Derivatives as Earth‐Abundant Oxygen Bifunctional Catalysts

Preparation and Electrochemical Properties of NiCo₂O₄ Nanospinels Supported on Graphene Derivatives as Earth‐Abundant Oxygen Bifunctional Catalysts

Modulation of Brønsted and Lewis Acid Centers for Ni_xCo₃₋_xO₄ Spinel Catalysts: Towards Efficient Catalytic Conversion of Lignin