Effect of Surface‐Adsorbed and Intercalated (Oxy)anions on the Oxygen Evolution Reaction

Hausmann, J. Niklas; Menezes, Prashanth W.

doi:10.1002/ange.202207279

Cited by 15 publications

(4 citation statements)

References 105 publications

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“…By probing the concentration of MoO 4 2− absorbed on the electrode surface, we find that MoO 4 2− tends to accumulate near the surface and this phenomenon is more evident after applying an anode voltage (Fig. 4f ) 45 , 46 . Combined with the constant atomic concentration of Mo in the electrolyte detected by ICP-OES, the reversible dissolution and precipitation of MoO 4 2− and NiMoO 4 at the electrochemical interface is responsible for stabilizing the MoO 4 2− .…”

Section: Resultsmentioning

confidence: 96%

A corrosion-resistant RuMoNi catalyst for efficient and long-lasting seawater oxidation and anion exchange membrane electrolyzer

et al. 2023

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Direct seawater electrolysis is promising for sustainable hydrogen gas (H2) production. However, the chloride ions in seawater lead to side reactions and corrosion, which result in a low efficiency and poor stability of the electrocatalyst and hinder the use of seawater electrolysis technology. Here we report a corrosion-resistant RuMoNi electrocatalyst, in which the in situ-formed molybdate ions on its surface repel chloride ions. The electrocatalyst works stably for over 3000 h at a high current density of 500 mA cm−2 in alkaline seawater electrolytes. Using the RuMoNi catalyst in an anion exchange membrane electrolyzer, we report an energy conversion efficiency of 77.9% and a current density of 1000 mA cm−2 at 1.72 V. The calculated price per gallon of gasoline equivalent (GGE) of the H2 produced is $ 0.85, which is lower than the 2026 technical target of $ 2.0/GGE set by the United Stated Department of Energy, thus, suggesting practicability of the technology.

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Section: Resultsmentioning

confidence: 96%

A corrosion-resistant RuMoNi catalyst for efficient and long-lasting seawater oxidation and anion exchange membrane electrolyzer

et al. 2023

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“…Recent preliminary studies show that trace chalcogenates, including SO 4 2– , SeO 4 2– , and PO 4 2– , are potent modifiers to optimize the OER active sites in metal alloys and metal oxides. − However, these chalcogenates originate from the conversion/reconstruction of the transition- metal chalcogenide surface during the OER process. As they are adsorbed on the surface of reconstructed oxyhydroxides in a uncontrollable way, , their effect on OER properties may interfere with the effect by reconstructed surface oxyhydroxides.…”

Section: Introductionmentioning

confidence: 99%

Oxidation State Engineering in Octahedral Ni by Anchored Sulfate to Boost Intrinsic Oxygen Evolution Activity

Zhang

Liu

et al. 2023

ACS Nano

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Promoting the electron occupancy of active sites to unity is an effective method to enhance the oxygen evolution reaction (OER) performance of spinel oxides, but it remains a great challenge. Here, an in situ approach is developed to modify the valence state of octahedral Ni cations in NiFe2O4 inverse spinel via surface sulfates (SO4 2–). Different from previous studies, SO4 2– is directly anchored on the spinel surface instead of forming from uncontrolled conversion or surface reconstruction. Experiment and theoretical calculations reveal the precise adsorption sites and spatial arrangement for SO4 2– species. As a main promoting factor, surface SO4 2– effectively converts the crystal field stable Ni state (t 2g 6 e g 2) to the near-unity e g electron state (t 2g 6 e g 1). Moreover, the inevitable oxygen vacancies (Vo) further optimize the energy barrier of the potential-determining step (from OH* to O*). This co-modification strategy enhances turnover frequency-based electrocatalytic activity about two orders higher than the control sample without surface sulfates. This work may provide insight into the OER activity enhancement mechanism by the oxyanion groups.

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“…[ 4 ] The adsorbates modify not only the electronic structure but also binding strength of the intermediates (including *OH and *OOH) for the OER process. The adsorbates are generated by the oxidation of a precatalyst element through consecutive etching– readsorption, the dissolution of a precursor (e.g., thiourea) in an alkaline solution, [ 5 ] and the SO 4 2– ions adsorption during the hydrothermal method (C 3 O 4 ). [ 6 ] To the best of our knowledge, research on the residual Ni sulfate originating from electrodeposition and its impact on OER activity is lacking.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ni Sulfate Residue on Oxygen Evolution Reaction (OER) in Porous NiFe@NiFe Layered Double Hydroxide

Park,

Kwon,

Lee

et al. 2024

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The development of cost‐effective and high‐performance oxygen evolution reaction (OER) catalysts is a significant challenge. This study presents the synthesis of binder‐free NiFe@NiFe layered double hydroxide (NNF) via one‐pot electrodeposition on carbon paper and Ni foam at high current densities. The presence of Ni sulfate residues on the prepared NNF is also investigated. The findings indicate that Ni sulfate significantly improves OER performance and durability. The sulfate content can be controlled by varying the method and duration of washing. NNF prepared through dipping (NNF‐D) exhibits outstanding OER activity with a low overpotential of 241 mV, which is 25 mV lower than that of NNF washed for 60 s (NNF‐W‐60 s) at 10 mA cm−2 in 1 m KOH. Furthermore, density functional theory analyses indicate that the Ni sulfate residue helps modify the electronic structure, thereby optimizing the binding strength of *OOH. This synthetic strategy is expected to inspire the development of next‐generation catalysts utilizing various adsorbates.

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Effect of Surface‐Adsorbed and Intercalated (Oxy)anions on the Oxygen Evolution Reaction

Cited by 15 publications

References 105 publications

A corrosion-resistant RuMoNi catalyst for efficient and long-lasting seawater oxidation and anion exchange membrane electrolyzer

A corrosion-resistant RuMoNi catalyst for efficient and long-lasting seawater oxidation and anion exchange membrane electrolyzer

Oxidation State Engineering in Octahedral Ni by Anchored Sulfate to Boost Intrinsic Oxygen Evolution Activity

Effect of Ni Sulfate Residue on Oxygen Evolution Reaction (OER) in Porous NiFe@NiFe Layered Double Hydroxide

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