Cobalt oxysulphide/hydroxide nanosheets with dual properties based on electrochromism and a charge storage mechanism

Kalasina, Saran; Kongsawatvoragul, Ketsuda; Phattharasupakun, Nutthaphon; Phattharaphuti, Phitchayapha

doi:10.1039/d0ra01714k

Cited by 44 publications

(12 citation statements)

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“…Recently, cobalt hydroxide/oxide nanostructures have been used as photoactive materials which can convert the photon energy into the electrical energy via the photovoltaic effect. ,− The photon energy under light illumination can provoke cobalt hydroxides to generate the charge carriers, excited electrons (e – ) and holes (h + ) in the valence band (VB) and conduction band (CB), respectively. This process can generate the extra photocurrent, leading to higher performance when Co(OH) 2 is served as the photoelectrode.…”

Section: Introductionmentioning

confidence: 99%

Reducing the Energy Band Gap of Cobalt Hydroxide Nanosheets with Silver Atoms and Enhancing Their Electrical Conductivity with Silver Nanoparticles

2021

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Although cobalt hydroxide (Co(OH)2) has been attracting attention in several applications, its photoelectrochemical property has not yet been fully investigated. In this work, tuning the energy band gap of Co(OH)2 nanosheets with silver atoms and enhancing their electrical conductivity with silver nanoparticles were then focused. A Ag-doped α-Co(OH)2 thin film was successfully synthesized via an electrodeposition method. The optical properties of the as-prepared materials were characterized by UV–vis and fluorescence lifetime spectroscopies and further confirmed by density functional theoretical calculation. It was found that Ag atoms between adjacent layers of Co(OH)2 can reduce its electronic band gap to 2.45 eV (α-Co(OH)2) as compared to 2.85 eV of β-Co(OH)2. In terms of electrochemical properties, silver nanoparticles (AgNPs) can enhance the electrical conductivity of Co(OH)2 nanosheets, leading to faster charge transfer reducing the internal resistance and significantly increasing the overall charge storage performance. Interestingly, under light illumination, Ag-doped α-Co(OH)2 exhibits ca. 0.8 times lower charge storage capacity as compared to that under the dark condition. This is because the photoelectrons can be recombined with the generated holes in the conduction band. The charge storage mechanisms of Ag-doped α-Co(OH)2 operated under dark conditions and light irradiation were further studied and confirmed using in situ electrochemical X-ray absorption spectroscopy (XAS). Overall, the in situ XAS supports the electrochemical result. This finding may pave a way to further develop photoactive advanced functional materials of metal hydroxides and oxides.

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Section: Introductionmentioning

confidence: 99%

Reducing the Energy Band Gap of Cobalt Hydroxide Nanosheets with Silver Atoms and Enhancing Their Electrical Conductivity with Silver Nanoparticles

2021

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“…The peaks corresponding to 780 and 795.08 eV of binding energy represent Co 2+ state whereas peaks corresponding to 781.18 and 797.08 eV represents the Co 3+ state. Additionally, two satellite peaks located at 784.8 and 803.28 eV also confirm the Co 2+ and Co 3+ oxidation states in Co 2p. , …”

Section: Resultsmentioning

confidence: 74%

“…Additionally, two satellite peaks located at 784.8 and 803.28 eV also confirm the Co 2+ and Co 3+ oxidation states in Co 2p. 50,51 Figure 4b represents the XPS analysis of Mn 2p, having a spin-orbit energy level separation of 10.7 eV between 2p 3/2 and 2p 1/2 states, which confirms the presence of Mn 3+ at spinel oxide sites. 52 Cu 2p spectra, can be deconvoluted into four major peaks, two are oxidation peaks representing Cu 2p 3/2 and Cu 2p 1/2 states and two are satellite peaks (Figure 4c).…”

Section: Compositional Analysismentioning

confidence: 73%

“…The peak at 532.28 eV represents the availability of large number of defects sites with low oxygen coordination. The peak at 532.68 eV represents the surface bounded OH group. , …”

Section: Resultsmentioning

confidence: 99%

“…The peak at 532.68 eV represents the surface bounded OH group. 50,56 3.6. Electrochemical Performance.…”

Section: Compositional Analysismentioning

confidence: 99%

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Hybrid Nanostructure of Sputter Decorated Nanodots of Ag₂O/AgO over Flower-like Mn–Co–Cu Ternary Metal Oxide for Electrocatalytic Oxygen Evolution Reaction

Raghav

Deepak

Roy

et al. 2023

ACS Appl. Energy Mater.

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Hybrid nanostructures of quaternary-composite metal oxide catalyst consisting of silver oxide nanodots over flower-like nanostructures of ternary metal oxide (MnCoCuO x ) were synthesized by a hydrothermal method, followed by DC magnetron sputtering. Multimetal ions in spinel structures are efficient OER catalysts as they have large number of active sites, enhancing the electron transfer process. The sputter decorated silver oxide nanodots enhances the electrochemically active surface area (ECSA) of the electrode, which further enhances the OER performance. X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), and Raman spectroscopy were used to validate the structure and composition of synthesized material. Oxygen evolution reaction (OER) activities of the synthesized catalysts were investigated by conducting linear scan voltammetry (LSV) at sweeping rate of 5 mV/s, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge−discharge (GCD). Quaternary-composite metal oxide catalysts were synthesized at various plasma powers, keeping other sputtering parameters fix. Silver oxide nanodots sputter decorated at 45 W over MnCoCuO x, showed the best catalytic properties for OER, having an overpotential of 83 mV via anodic scan and 110 mV via cathodic scan, Tafel slope of 65 mVdec −1 , ECSA of 826 cm 2 , mass activity of 143.7 A g −1 , and a turn over frequency (TOF) of 0.039 s −1 . The symmetric device fabricated using the best performing electrode as cathode and anode displayed efficient water splitting activity, achieving a current density of 10 mA/cm 2 at 1.37 V vs RHE, which is close to thermodynamic value of 1.23 V.

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Extended Range of Ratiometric Luminescence Codes with Ce³⁺ Modified Gd₂O₂S:Er³⁺,Yb³⁺ Shortwave Infrared Phosphors

Cosgun Ergene,

Madirov,

Coetsee‐Hugo

et al. 2024

Advanced Optical Materials

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Lanthanide (Ln3+) based luminescent materials, with their distinctive emission spectra, offer opportunities to develop novel coding patterns for various applications, including Tracer Based Sorting (TBS). TBS uses trace amounts of inorganic phosphors and is a promising method for sorting plastics based on criteria beyond plastic type. This study investigates the synergistic effect of co‐doping with Ce3+ to enhance Er3+ luminescence at ≈1550 nm (with a maximum photoluminescence quantum yield (PLQY) of 5.7%) while significantly reducing Yb3+ luminescence at ≈1000 nm. The underlying mechanisms of these properties are analyzed using absolute PLQY measurements in an integrating sphere, luminescence decay studies, and X‐ray photoelectron spectroscopy. Hyperspectral shortwave infrared imaging reveals an extended range of unique tracer combinations based on ratiometric intensity measurements, particularly when the Yb3+/Er3+/Ce3+ tracers are mixed with a single‐doped Yb3+ tracer, compared to simple mixtures of Ce3+‐free Yb3+/Er3+ and Yb3+ tracers. Therefore, the use of the tri‐doped Yb3+/Er3+/Ce3+ Gd2O2S tracer increases the diversity of available luminescent tracers that may be of potential interest in the identification and sorting of plastic waste using the TBS process.

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Cobalt oxysulphide/hydroxide nanosheets with dual properties based on electrochromism and a charge storage mechanism

Abstract: The charge storage mechanism of mixed cobalt oxysulphide/hydroxide materials having electrochromic properties was investigated.

Cited by 44 publications

References 47 publications

Reducing the Energy Band Gap of Cobalt Hydroxide Nanosheets with Silver Atoms and Enhancing Their Electrical Conductivity with Silver Nanoparticles

Reducing the Energy Band Gap of Cobalt Hydroxide Nanosheets with Silver Atoms and Enhancing Their Electrical Conductivity with Silver Nanoparticles

Hybrid Nanostructure of Sputter Decorated Nanodots of Ag₂O/AgO over Flower-like Mn–Co–Cu Ternary Metal Oxide for Electrocatalytic Oxygen Evolution Reaction

Extended Range of Ratiometric Luminescence Codes with Ce³⁺ Modified Gd₂O₂S:Er³⁺,Yb³⁺ Shortwave Infrared Phosphors

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Cobalt oxysulphide/hydroxide nanosheets with dual properties based on electrochromism and a charge storage mechanism

Abstract: The charge storage mechanism of mixed cobalt oxysulphide/hydroxide materials having electrochromic properties was investigated.

Cited by 44 publications

References 47 publications

Reducing the Energy Band Gap of Cobalt Hydroxide Nanosheets with Silver Atoms and Enhancing Their Electrical Conductivity with Silver Nanoparticles

Reducing the Energy Band Gap of Cobalt Hydroxide Nanosheets with Silver Atoms and Enhancing Their Electrical Conductivity with Silver Nanoparticles

Hybrid Nanostructure of Sputter Decorated Nanodots of Ag2O/AgO over Flower-like Mn–Co–Cu Ternary Metal Oxide for Electrocatalytic Oxygen Evolution Reaction

Extended Range of Ratiometric Luminescence Codes with Ce3+ Modified Gd2O2S:Er3+,Yb3+ Shortwave Infrared Phosphors

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Product

Resources

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Hybrid Nanostructure of Sputter Decorated Nanodots of Ag₂O/AgO over Flower-like Mn–Co–Cu Ternary Metal Oxide for Electrocatalytic Oxygen Evolution Reaction

Extended Range of Ratiometric Luminescence Codes with Ce³⁺ Modified Gd₂O₂S:Er³⁺,Yb³⁺ Shortwave Infrared Phosphors