Activating the lattice oxygen oxidation mechanism in amorphous molybdenum cobalt oxide nanosheets for water oxidation

Wang, Xiang; Xing, Congcong; Liang, Zhifu; Guardia, Pablo; Han, Xu; Zuo, Yong; Llorca, Jordi; Arbiol, Jordi; Li, Junshan; Cabot, Andreu

doi:10.1039/d1ta09657e

Cited by 32 publications

(27 citation statements)

References 66 publications

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“…In a second step, the ZIF-67 was etched, and Co was partially exchanged with Mo using ammonium molybdate both as the Mo source and etching agent. In this step, ammonium molybdate hydrolyzes generating protons (H + ) that slowly etch the ZIF-67 releasing Co 2+ ions and hydroxides (OH – ) that drive the precipitation of 2-methylimidazole and molybdate and cobalt ions. , Thus, upon hydrolysis and etching processes with ammonium molybdate, the crystalline ZIF-67 dodecahedron particles were transformed into an amorphous and layered material, as observed in Figures b and S1.…”

Section: Resultsmentioning

confidence: 99%

Cobalt Molybdenum Nitride-Based Nanosheets for Seawater Splitting

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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The development of cost-effective bifunctional catalysts for water electrolysis is both a crucial necessity and an exciting scientific challenge. Herein, a simple approach based on a metal–organic framework sacrificial template to preparing cobalt molybdenum nitride supported on nitrogen-doped carbon nanosheets is reported. The porous structure of produced composite enables fast reaction kinetics, enhanced stability, and high corrosion resistance in critical seawater conditions. The cobalt molybdenum nitride-based electrocatalyst is tested toward both oxygen evolution reaction and hydrogen evolution reaction half-reactions using the seawater electrolyte, providing excellent performances that are rationalized using density functional theory. Subsequently, the nitride composite is tested as a bifunctional catalyst for the overall splitting of KOH-treated seawater from the Mediterranean Sea. The assembled system requires overpotentials of just 1.70 V to achieve a current density of 100 mA cm–2 in 1 M KOH seawater and continuously works for over 62 h. This work demonstrates the potential of transition-metal nitrides for seawater splitting and represents a step forward toward the cost-effective implementation of this technology.

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Section: Resultsmentioning

confidence: 99%

Cobalt Molybdenum Nitride-Based Nanosheets for Seawater Splitting

Wang

et al. 2022

ACS Appl. Mater. Interfaces

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“…to facilitate the electron‐transfer process. Li et al [ 130 ] synthesized ultrathin amorphous MoCo x O y nanosheets with porous structure via an ion etching method. The doping of Mo with higher electronegativity triggered the participation of lattice oxygen in OER.…”

Section: Perspective and Conclusionmentioning

confidence: 99%

Understanding of Oxygen Redox in the Oxygen Evolution Reaction

et al. 2022

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The electron‐transfer process during the oxygen evolution reaction (OER) often either proceeds solely via a metal redox chemistry (adsorbate evolution mechanism (AEM), with metal bands around the Fermi level) or an oxygen redox chemistry (lattice oxygen oxidation mechanism (LOM), with oxygen bands around the Fermi level). Unlike the AEM, the LOM involves oxygen redox chemistry instead of metal redox, which leads to the formation of a direct oxygen–oxygen (OO) bond. As a result, such a process is able to bypass the rate‐determining step, that is, OO bonding, in AEM, which highlights the critical advantage of LOM as compared to the conventional AEM. Thus, it has been well reported that LOM‐based catalysts are able to demonstrate higher OER activities as compared to AEM‐based catalysts. Here, a comprehensive understanding of the oxygen redox in LOM and all documented and possible characterization techniques that can be used to identify the oxygen redox are reviewed. This review will interpret the origins of oxygen redox in the reported LOM‐based electrocatalysts and the underlying science of LOM‐induced surface reconstruction in transition metal oxides. Finally, perspectives on the future development of LOM electrocatalysts are also provided.

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“…[46] The introduction of oxygen vacancies into the lattice can effectively adjust the electronic structure, activate oxygen ligands, and promote the redox of lattice oxygen. [8,39,47,48] Oxygen vacancies have a modulating effect on metaloxygen covalency as well as the positions of metal d-band and oxygen 2p-band. [49,50,51] Theoretical investigations indicate that when oxygen vacancy exists, the gap between the metal d-band and oxygen p-band becomes smaller (Figure 4c).…”

Section: Vacancy Engineeringmentioning

confidence: 99%

Mechanisms of Oxygen Evolution Reaction in Metal Oxides: Adsorbate Evolution Mechanism versus Lattice Oxygen Mechanism

Suo¹,

Wei²

2023

MatLab

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Water electrolysis provides a promising technology for hydrogen production, but the sluggish four-electron conversion-process of the oxygen evolution reaction results in high overpotential and a low efficiency of water splitting. To rationalize and improve the performance of oxygen evolution reaction, it is crucial to understand the electrochemical mechanisms occurring in cells and monitor the structural changes of newly developed catalysts. As the most recognized mechanisms, the adsorbate evolution mechanism and the lattice oxygen mechanism have been utilized to explain the physical and chemical behaviors of the oxygen evolution reaction. Thus, we herein provide a perspective on these two paths by summarizing the recent progresses in oxygen evolution reactions and building fundamental connections between material designs and the two mechanisms. Insights from this work offer solution to address the current challenges and limitations for the water oxidation.

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Activating the lattice oxygen oxidation mechanism in amorphous molybdenum cobalt oxide nanosheets for water oxidation

Abstract: The cost-effective deployment of several key energy technologies, such as water electrolysis, CO2 electroreduction and metal-air batteries, relies on the design and engineering of cost-effective catalysts able to accelerate the...

Cited by 32 publications

References 66 publications

Cobalt Molybdenum Nitride-Based Nanosheets for Seawater Splitting

Cobalt Molybdenum Nitride-Based Nanosheets for Seawater Splitting

Understanding of Oxygen Redox in the Oxygen Evolution Reaction

Mechanisms of Oxygen Evolution Reaction in Metal Oxides: Adsorbate Evolution Mechanism versus Lattice Oxygen Mechanism

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