Facile control of surface reconstruction with Co2+ or Co3+-rich (oxy)hydroxide surface on ZnCo phosphate for large-current-density hydrogen evolution in alkali

Liu, H.; Cao, Shoufu; Zhang, J.; Liu, Songyao; Chen, C.; Zhang, Y.; Wei, Shuxian; Wang, Z.; Lu, Xiaoqing

doi:10.1016/j.mtphys.2021.100448

Cited by 16 publications

(11 citation statements)

References 47 publications

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“…For example, Lu et al synthesized ZnCo phosphate as HER electrocatalysts and revealed that the reconstruction of Co 2+ -rich hydroxide was induced by electrochemical etching of PO 4 3− and Zn 2+ . [141] The resulting interface between the ZnCo phosphate and cobalt hydroxyl oxide was proved to promote the charge transfer from atomic Co to the surrounding environment, thus increasing the HER activity. Shao et al developed conductive monoclinic SrIrO 3 perovskite as excellent HER electrocatalysts and revealed the pivotal role of lattice Sr 2+ leaching in triggering the self-reconstruction.…”

Section: Partial Dissolutionmentioning

confidence: 99%

Surface Reconstruction of Water Splitting Electrocatalysts

Zeng

Zhao

Huang

et al. 2022

Advanced Energy Materials

154

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Gibbs free energy (ΔG) of water splitting reaction is 237.2 kJ mol −1 , corresponding to a theoretical voltage of 1.23 V. [3] However, the existence of electrochemical/concentration polarization and solution resistance can increase the actual voltage of water electrolysis to much beyond 1.23 V. Particularly, the OER involves a complicated four-electron transfer process, which results in a sluggish kinetics thus has long been the bottleneck. [4] Therefore, it is necessary to explore efficient and robust electrocatalysts to reduce the overpotential of water electrolysis and the extra electric energy consumption. Although noble electrocatalysts, such as Pt, RuO 2 and IrO 2 , are recognized as the most efficient electrocatalysts for water electrolysis, their high scarcity and instability severely impede large-scale applications. [5] Recently, considerable effort has been focused on nonnoble transition-metal materials as viable alternatives for water splitting. Understanding the intrinsic catalytic mechanism and real active sites of these catalysts will benefit the rational design and application of high-efficiency catalysts.With the development of in situ characterization technologies, more reports have revealed that the original electrocatalyst (so-called "pre-catalyst") surface sites would undergo dynamic reconstruction and transform into real reactive species. [6] This in situ reconstruction process could tune the electrocatalytic behaviors such as adsorption, activation, and desorption, thus improving the catalytic performance. [7] On this basis, many researchers utilized the pre-reconstruction of electrocatalysts to obtain a large number of active species for the catalytic reactions. [8] It has been found that the intrinsic properties of the pre-catalysts, such as composition, atomic arrangement, porosity, and crystallinity, would affect the reconstruction rate, reconstruction degree, and catalytic activity of the reconstructed species. [9] Moreover, the reaction conditions also affect the reconstruction process, such as electrochemical operation, applied potential, electrolyte concentration, and pH. [6a] Therefore, tuning the reconstruction process to generate abundant active sites with high intrinsic activity is an effective strategy to boost the catalytic performance of electrocatalysts.Although some influential review articles on the reconstruction of catalysts during water electrolysis have emerged, [10] most of them focus on the discovery and characterization of the reconstruction phenomenon, less on the regulation of the reconstruction process. In addition, reconstructed catalysts for Water electrolysis is regarded as an efficient and green method to produce hydrogen gas, a clean energy carrier that holds the key to solving global energy problems. So far, the efficiency and large-scale application of water electrolysis are restricted by the electrocatalytic activity of applied catalysts. Recently, the reconstruction phenomenon of electrocatalysts during a catalytic reaction has been discovered, which ...

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Section: Partial Dissolutionmentioning

confidence: 99%

Surface Reconstruction of Water Splitting Electrocatalysts

Zeng

Zhao

Huang

et al. 2022

Advanced Energy Materials

154

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“…1−5 However, the electrocatalytic activity of CoSe 2 is far lower than that of a Pt-based catalyst due to the lack of exposed active sites and low electrical conductivity. 4,6,7 Hence, approaches to further improve the electrocatalytic activity of CoSe 2 are required. 8−13 Methods such as doping and creating vacancies to increase the exposed active sites and improve the electrical conductivity appeared to be feasible to greatly improve the electrocatalytic activity of CoSe 2 .…”

Section: ■ Introductionmentioning

confidence: 99%

“…Cobalt diselenide (CoSe 2 ) as a member of layered transition-metal dichalcogenides exhibited promise and has increasingly attracted attention in electrocatalytic hydrogen evolution reaction (HER) due to its surface sites similar to active metal centers of hydrogenase and the unsaturated 3d electron. − However, the electrocatalytic activity of CoSe 2 is far lower than that of a Pt-based catalyst due to the lack of exposed active sites and low electrical conductivity. ,, Hence, approaches to further improve the electrocatalytic activity of CoSe 2 are required. − …”

Section: Introductionmentioning

confidence: 99%

Phase Transition in Cobalt Selenide with a Greatly Improved Electrocatalytic Activity in Hydrogen Evolution Reactions

Sun

et al. 2022

ACS Sustainable Chem. Eng.

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Surface properties such as electronic structures and valence state determine the electrocatalytic activity in hydrogen evolution reactions (HERs). Herein, we prepared a novel orthorhombic CoSe 2 -NC (o-CoSe 2 -NC) electrocatalyst from hexagonal CoSe-NC (h-CoSe-NC) via a phase-transition method. As-prepared o-CoSe 2 -NC exhibited excellent HER activity with 147 mV at 10 mA cm −2 and a high stability (24 h). Density functional theory results revealed that the active sites for h-CoSe-NC in electrocatalytic hydrogen evolutions were the anion Se sites (ΔG H* = 0.34 eV). After the phase transition, Co sites (ΔG H* = 0.20 eV) in o-CoSe 2 -NC became more active than Se sites. Moreover, the dband central of Co in o-CoSe 2 -NC was closer to the Fermi level than that of h-CoSe-NC after the phase transition. Also, o-CoSe 2 -NC exhibited a metallic behavior with excellent electrical conductivity. This work not only prepared cost-effective cobalt selenide-based electrocatalysts but also highlighted the significance of the crystal phase in electrocatalytic hydrogen evolutions.

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“…For example, the permeation of zinc ions by cyclic voltammetry (CV) cycling under reduction potential is reported to generate the Co 3+ -rich oxyhydroxide for ZnCoPi. 19 The structural flexibility of borophosphate materials enables self-adjusting of the electronic structure, and their rich chemistry can provide a huge engineering space to boost the OER. 20 Furthermore, the hydrogen phosphate ion (HPO 4 2− ) can be applied as a proton acceptor during OER.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Moreover, different cations and anions components in the cobalt-based electrocatalysts can induce the reconstruction for cobalt (oxy)hydroxide and contribute to the diverse kinetic process. For example, the permeation of zinc ions by cyclic voltammetry (CV) cycling under reduction potential is reported to generate the Co 3+ -rich oxyhydroxide for ZnCoPi . The structural flexibility of borophosphate materials enables self-adjusting of the electronic structure, and their rich chemistry can provide a huge engineering space to boost the OER .…”

Section: Introductionmentioning

confidence: 99%

Phosphate Group Dependent Metallic Co(OH)₂ toward Hydrogen Evolution in Alkali for the Industrial Current Density

Liu

Cao

et al. 2022

ACS Sustainable Chem. Eng.

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Developing efficient and low-cost electrocatalysts is critical for hydrogen evolution by water splitting. Nonsubjective reconstruction is one of the main issues that induces difficulty to develop and understand the well-defined structure during the electrocatalysis. By studying the anion-exchange between phosphate and hydroxide, cobalt hydroxide nanosheets incorporated with phosphate inherited from cobalt phosphate are obtained, which provides a new case of metallic transition metal hydroxide. Benefiting from more exposed active sites, effective electron transport, and optimized electronic structure, the residual phosphate in two-dimensional Co(OH) 2 gives rise to significant improvement in alkaline hydrogen evolution. Particularly, it can survive at 1600 mA cm −2 and maintain stability over 100 h under industrial conditions (6 M KOH at 60 °C). Density functional theory calculations and the confirmatory experiments of reverse anion-exchange from Co(OH) 2 are investigated to confirm the successful engineering of metallic character and electronic structure. This work provides a facile modification of practical electrodes with phosphate groups for industrial water electrolysis as well as gaining insights into the reconstruction of cobalt-based electrocatalysts in alkali to become an effective catalyst.

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Facile control of surface reconstruction with Co2+ or Co3+-rich (oxy)hydroxide surface on ZnCo phosphate for large-current-density hydrogen evolution in alkali

Cited by 16 publications

References 47 publications

Surface Reconstruction of Water Splitting Electrocatalysts

Surface Reconstruction of Water Splitting Electrocatalysts

Phase Transition in Cobalt Selenide with a Greatly Improved Electrocatalytic Activity in Hydrogen Evolution Reactions

Phosphate Group Dependent Metallic Co(OH)₂ toward Hydrogen Evolution in Alkali for the Industrial Current Density

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Facile control of surface reconstruction with Co2+ or Co3+-rich (oxy)hydroxide surface on ZnCo phosphate for large-current-density hydrogen evolution in alkali

Cited by 16 publications

References 47 publications

Surface Reconstruction of Water Splitting Electrocatalysts

Surface Reconstruction of Water Splitting Electrocatalysts

Phase Transition in Cobalt Selenide with a Greatly Improved Electrocatalytic Activity in Hydrogen Evolution Reactions

Phosphate Group Dependent Metallic Co(OH)2 toward Hydrogen Evolution in Alkali for the Industrial Current Density

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Product

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Phosphate Group Dependent Metallic Co(OH)₂ toward Hydrogen Evolution in Alkali for the Industrial Current Density