Formation mechanisms of Ni2P nanocrystals using XANES and EXAFS spectroscopy

Seo, Hye-Ryun; Cho, Kye-Sung; Lee, Yong‐Kul

doi:10.1016/j.mseb.2010.10.013

Cited by 37 publications

(17 citation statements)

References 30 publications

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“…Microstructural analysis using extended X-ray fine structure (EXAFS) analysis of the Ni K edge (Fig. 6c ) reinforced these observations; after deformation, the FFT signal changed completely, with Ni-O and Ni-Ni peaks developing in a manner consistent with the Ni(OH) 2 phase 31 , 32 . After five cycles, the Ni-P signal dropped dramatically and almost diminished through 3,000 CV scans (Supplementary Fig.…”

Section: Discussionmentioning

confidence: 68%

“…6b ). The initially prepared Ni 2 P/C showed a typical Ni-P peak (orange) and a surface Ni-O peak (yellow) 31 , 32 . After repeated OER cycles, a new main peak (violet) assigned to Ni-OH appeared 33 , 34 .…”

Section: Discussionmentioning

confidence: 99%

“…Carbon-supported Ni 2 P nanoparticles were prepared by thermal decomposition following a previously reported method 31 . First, nickel(II) acetylacetonate (Ni(acac) 2 ) and (CH 3 (CH 2 ) 7 ) 3 P were mixed and stirred at 90 °C in an inert atmosphere.…”

Section: Methodsmentioning

confidence: 99%

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Anomalous in situ Activation of Carbon-Supported Ni2P Nanoparticles for Oxygen Evolving Electrocatalysis in Alkaline Media

Chung

Jang

et al. 2017

Sci Rep

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Electrochemical water splitting is one of the most promising systems by which to store energy produced from sustainable sources, such as solar and wind energy. Designing robust and stable electrocatalysts is urgently needed because of the relatively sluggish kinetics of the anodic reaction, i.e. the oxygen evolution reaction (OER). In this study, we investigate the anomalous in situ activation behaviour of carbon-supported Ni2P nanoparticles (Ni2P/C) during OER catalysis in alkaline media. The activated Ni2P/C shows an exceptionally high activity and stability under OER conditions in which the overpotential needed to achieve 10 mA cm−2 was reduced from approximately 350 mV to approximately 300 mV after 8,000 cyclic voltammetric scans. In situ and ex situ characterizations indicate that the activity enhancement of Ni2P catalysts is due to a favourable phase transformation of the Ni centre to β-NiOOH, including increases in the active area induced by structural deformation under the OER conditions. These findings provide new insights towards designing transition metal/phosphide-based materials for an efficient water splitting catalyst.

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Section: Discussionmentioning

confidence: 68%

Section: Discussionmentioning

confidence: 99%

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Anomalous in situ Activation of Carbon-Supported Ni2P Nanoparticles for Oxygen Evolving Electrocatalysis in Alkaline Media

Chung

Jang

et al. 2017

Sci Rep

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“…8 In a typical synthesis of Ni 2 P nanoparticles in OAm, two stages occur: (i) the Ni precursor (e.g., Ni(acac) 2 ) decomposing to form Ni nanoparticles above 200 °C and (ii) the insertion of P to form a Ni 2 P phase above 300 °C. 6 By meticulous tuning of the synthesis parameters, such as the P/Ni precursor ratio and OAm quantity, the size of the Ni 2 P particles can be tuned in the range of 5−50 nm, [4][5][6]9 while Ni 2 P particles less than 2 nm have not been obtained by the liquid-phase synthesis in the open literature. The difficulty in synthesizing sub-2 nm Ni 2 P particles stems from the need to accommodate for the insertion of P during crystal growth during the synthesis.…”

Section: Introductionmentioning

confidence: 99%

“…Clearly, this takes an extended length of time during which the particles grow beyond 2 nm. 9 So, it is difficult to achieve smaller size Ni 2 P nanoparticles solely by modifying the ratio of the precursors or changing the solvent and the surfactants. In this work, synthesis toward obtaining ultrafine Ni 2 P crystals was attempted, while comparison of their catalytic performance with that of bulk and nanoparticles of Ni 2 P is presented.…”

Section: Introductionmentioning

confidence: 99%

Ni₂P Nanoparticles Embedded in Mesoporous SiO₂ for Catalytic Hydrogenation of SO₂ to Elemental S

Baker

Anjum

et al. 2021

ACS Appl. Nano Mater.

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Highly active nickel phosphide (Ni2P) nanoclusters confined in a mesoporous SiO2 catalyst were synthesized by a two-step process targeting tight control over the Ni2P size and phase. The Ni precursor was incorporated into the MCM-41 matrix by one-pot synthesis, followed by the phosphorization step, which was accomplished in oleylamine with trioctylphosphine at 300 °C so to achieve the phase transformation from Ni to Ni2P. For benchmarking, Ni confined by the mesoporous SiO2 (absence of phosphorization) and 11 nm Ni2P nanoparticles (absence of SiO2) was also prepared. From the microstructural analysis, it was found that the growth of Ni2P nanoclusters was restricted by the mesoporous channels, thus forming ultrafine and highly dispersed Ni2P nanoclusters (<2 nm). The above approach led to promising catalytic performance following the order u-Ni2P@m-SiO2 > n-Ni2P > u-Ni@m-SiO2 > c-Ni2P in the selective hydrogenation of SO2 to S. In particular, u-Ni2P@m-SiO2 exhibited SO2 conversions of 94% at 220 °C and ∼99% at 240 °C, which are higher than the 11 nm stand-alone Ni2P particles (43% at 220 °C and 94% at 320 °C), highlighting the importance of the role played by SiO2 in stabilizing ultrafine nanoparticles of Ni2P. The reaction activation energy E a over u-Ni2P@m-SiO2 is ∼33 kJ/mol, which is lower than those over n-Ni2P (∼36 kJ/mol) and c-Ni2P (∼66 kJ/mol), suggesting that the reaction becomes energetically favored over the ultrafine Ni2P nanoclusters.

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25th Anniversary Article: Exploring Nanoscaled Matter from Speciation to Phase Diagrams: Metal Phosphide Nanoparticles as a Case of Study

et al. 2013

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The notions of nanoscale "phase speciation" and "phase diagram" are defined and discussed in terms of kinetic and thermodynamic controls, based on the case of metal phosphide nanoparticles. After an overview of the most successful synthetic routes for these exotic nanomaterials, the cases of InP, Ni2 P, Ni12 P5 and Pdx Py are discussed in detail to highlight the relationship between composition, structure, and size at the nanoscale. The influence of morphology is discussed next by comparing the behavior of Cu3 P nanophases with those of Nix Py , FeP/Fe2 P, and CoP/Co2 P. Perspectives provide the reader with methodological guidelines for further investigation of nanoscale "phase diagrams", and their use for optimized synthesis of new functional nanomaterials.

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Formation mechanisms of Ni2P nanocrystals using XANES and EXAFS spectroscopy

Cited by 37 publications

References 30 publications

Anomalous in situ Activation of Carbon-Supported Ni2P Nanoparticles for Oxygen Evolving Electrocatalysis in Alkaline Media

Anomalous in situ Activation of Carbon-Supported Ni2P Nanoparticles for Oxygen Evolving Electrocatalysis in Alkaline Media

Ni₂P Nanoparticles Embedded in Mesoporous SiO₂ for Catalytic Hydrogenation of SO₂ to Elemental S

25th Anniversary Article: Exploring Nanoscaled Matter from Speciation to Phase Diagrams: Metal Phosphide Nanoparticles as a Case of Study

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Formation mechanisms of Ni2P nanocrystals using XANES and EXAFS spectroscopy

Cited by 37 publications

References 30 publications

Anomalous in situ Activation of Carbon-Supported Ni2P Nanoparticles for Oxygen Evolving Electrocatalysis in Alkaline Media

Anomalous in situ Activation of Carbon-Supported Ni2P Nanoparticles for Oxygen Evolving Electrocatalysis in Alkaline Media

Ni2P Nanoparticles Embedded in Mesoporous SiO2 for Catalytic Hydrogenation of SO2 to Elemental S

25th Anniversary Article: Exploring Nanoscaled Matter from Speciation to Phase Diagrams: Metal Phosphide Nanoparticles as a Case of Study

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Ni₂P Nanoparticles Embedded in Mesoporous SiO₂ for Catalytic Hydrogenation of SO₂ to Elemental S