Fabrication of Multi-Vacancy-Defect MWCNTs by the Removal of Metal Oxide Nanoparticles

Kim, Tae Hyeong; Nam, Dong Hwan; Kim, Dohyun; Leem, Gyu; Lee, Seung–Hyun

doi:10.3390/polym14142942

Cited by 4 publications

(1 citation statement)

References 53 publications

(52 reference statements)

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“…[4] Therefore, designing low-cost bifunctional electrocatalysts of various transition metal-oxides, -sulfides, -phosphides, -nitrides, and so on, along with improving their physicochemical properties through secondary element doping, defect creation, and surface engineering using multi-phase compositions to improve both intrinsic as well as extrinsic electrocatalytic properties has attracted increasing attention. [5][6][7][8][9][10][11][12][13][14][15] Although certain electrocatalysts showed excellent electrocatalytic performance for individual half-cell OER or HER reactions in three-electrode configuration, [16][17][18] the development of both OER and HER active bifunctional electrocatalysts in the same electrolyte is crucial to saving the time and the cost for developing large-scale affordable electrolyzers, but still limited to lack of innovative synthesis protocol and judicious choice of the active materials.…”

Section: Introductionmentioning

confidence: 99%

Metal–Organic Framework–Derived Mesoporous B‐Doped CoO/Co@N‐Doped Carbon Hybrid 3D Heterostructured Interfaces with Modulated Cobalt Oxidation States for Alkaline Water Splitting

Cha

Singh

Maibam

et al. 2023

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Heteroatom‐doped transition metal‐oxides of high oxygen evolution reaction (OER) activities interfaced with metals of low hydrogen adsorption energy barrier for efficient hydrogen evolution reaction (HER) when uniformly embedded in a conductive nitrogen‐doped carbon (NC) matrix, can mitigate the low‐conductivity and high‐agglomeration of metal‐nanoparticles in carbon matrix and enhances their bifunctional activities. Thus, a 3D mesoporous heterostructure of boron (B)‐doped cobalt‐oxide/cobalt‐metal nanohybrids embedded in NC and grown on a Ni foam substrate (B‐CoO/Co@NC/NF) is developed as a binder‐free bifunctional electrocatalyst for alkaline water‐splitting via a post‐synthetic modification of the metal–organic framework and subsequent annealing in different Ar/H2 gas ratios. B‐CoO/Co@NC/NF prepared using 10% H2 gas (B‐CoO/Co@NC/NF [10% H2]) shows the lowest HER overpotential (196 mV) and B‐CoO/Co@NC/NF (Ar), developed in Ar, shows an OER overpotential of 307 mV at 10 mA cm−2 with excellent long‐term durability for 100 h. The best anode and cathode electrocatalyst‐based electrolyzer (B‐CoO/Co@NC/NF (Ar)(+)//B‐CoO/Co@NC/NF (10% H2)(−)) generates a current density of 10 mA cm−2 with only 1.62 V with long‐term stability. Further, density functional theory investigations demonstrate the effect of B‐doping on electronic structure and reaction mechanism of the electrocatalysts for optimal interaction with reaction intermediates for efficient alkaline water‐splitting which corroborates the experimental results.

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Section: Introductionmentioning

confidence: 99%

Metal–Organic Framework–Derived Mesoporous B‐Doped CoO/Co@N‐Doped Carbon Hybrid 3D Heterostructured Interfaces with Modulated Cobalt Oxidation States for Alkaline Water Splitting

Cha

Singh

Maibam

et al. 2023

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Photocatalytic Synthesis of Ultrafine Pt Electrocatalysts with High Stability Using TiO₂‐Decorated N‐Doped Carbon as Composite Support

et al. 2023

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Commercial Pt/C (Com. Pt/C) electrocatalysts are considered optimal for oxygen reduction and hydrogen evolution reactions (ORR and HER). However, their high Pt content and poor stability restrict their large-scale application. In this study, photocatalytic synthesis was used to reduce ultrafine Pt nanoparticles in-situ on a composite support of TiO 2 -decorated nitrogen-doped carbon (TiO 2 À NC). The nitrogen-doped carbon had a large surface area and electronic effects that ensured the uniform dispersion of TiO 2 nanoparticles to form a highly photoactive and stable support. TiO 2 À NC served as a composite support that enhanced the dispersibility and stability of ultra-fine Pt electrocatalyst, owing to the presence of N sites and the strong metal-support interaction. Relative to Com. Pt/C, the asobtained Pt/TiO 2 À NC had positive shifts of 44 and 10 mV in the ORR half-wave potential and HER overpotential at À 10 mA cm À 2 , respectively. After an accelerated durability test, Pt/TiO 2 À NC had lower losses in electrochemical specific area (0.7 %) and electrocatalytic activity (0 mV shift) than Com. Pt/C (25.6 %, 22 mV shift). These results indicate that the developed strategy enabled the facile synthesis and stabilization of ultrafine Pt nanoparticles, which improved the utilization efficiency and long-term stability of Pt-based electrocatalysts.

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Pre-concentration of pesticides in water using isophorone diamine multiwalled carbon nanotubes-based solid-phase extraction technique and analysis by gas chromatography–mass spectrometry

Sethoga,

Magadzu,

Ambushe

2023

Int. J. Environ. Sci. Technol.

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The existence of pesticides in water at ultra-trace levels necessitates the use of a suitable pre-concentration method for their detection. The objective of this study was to develop an ultra-synthetic adsorbent to extract chlorpyrifos (CPF) and imazalil (IMA) pesticides in water. X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy confirm that both oxidised and isophorone diamine multiwalled carbon nanotubes (IPD-MWCNTs) were successfully prepared with an intact structure; which was further confirmed by transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS). The Brunauer–Emmet–Teller (BET) showed a high surface area of both oxidised and IPD-MWCNTs, which is linked to the formation of additional active sites. TGA further showed that the nanocomposites were highly stable within the pesticides quantification operating temperature. CPF and IMA were recovered using a low dosage of IPD-MWCNTs adsorbent (0.030 g) and eluted by a combined solvent (ethanol and chloroform (50:50, v/v)). The adsorbent was reusable over seven repeated cycles, with an acceptable percentage relative standard deviation (%RSD) ranging from 3 to 8%. The IPD-MWCNTs adsorption sites are highly stable and cannot be easily fouled, as compared to that of oxidised MWCNTs. Lower limits of detection (LOD) and quantification (LOQ) for CPF (0.026 and 0.078 µg.L−1) and IMA (0.033 and 0.100 µg.L−1) were achieved. Better recoveries for both analytes at low and high concentrations (as well as in real water samples) were obtained by IPD-MWCNTs whereas a conventional adsorbent (i.e. polymeric reverse phase) can only achieve better recoveries at high concentrations.

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Fabrication of Multi-Vacancy-Defect MWCNTs by the Removal of Metal Oxide Nanoparticles

Cited by 4 publications

References 53 publications

Metal–Organic Framework–Derived Mesoporous B‐Doped CoO/Co@N‐Doped Carbon Hybrid 3D Heterostructured Interfaces with Modulated Cobalt Oxidation States for Alkaline Water Splitting

Metal–Organic Framework–Derived Mesoporous B‐Doped CoO/Co@N‐Doped Carbon Hybrid 3D Heterostructured Interfaces with Modulated Cobalt Oxidation States for Alkaline Water Splitting

Photocatalytic Synthesis of Ultrafine Pt Electrocatalysts with High Stability Using TiO₂‐Decorated N‐Doped Carbon as Composite Support

Pre-concentration of pesticides in water using isophorone diamine multiwalled carbon nanotubes-based solid-phase extraction technique and analysis by gas chromatography–mass spectrometry

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Fabrication of Multi-Vacancy-Defect MWCNTs by the Removal of Metal Oxide Nanoparticles

Cited by 4 publications

References 53 publications

Metal–Organic Framework–Derived Mesoporous B‐Doped CoO/Co@N‐Doped Carbon Hybrid 3D Heterostructured Interfaces with Modulated Cobalt Oxidation States for Alkaline Water Splitting

Metal–Organic Framework–Derived Mesoporous B‐Doped CoO/Co@N‐Doped Carbon Hybrid 3D Heterostructured Interfaces with Modulated Cobalt Oxidation States for Alkaline Water Splitting

Photocatalytic Synthesis of Ultrafine Pt Electrocatalysts with High Stability Using TiO2‐Decorated N‐Doped Carbon as Composite Support

Pre-concentration of pesticides in water using isophorone diamine multiwalled carbon nanotubes-based solid-phase extraction technique and analysis by gas chromatography–mass spectrometry

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Photocatalytic Synthesis of Ultrafine Pt Electrocatalysts with High Stability Using TiO₂‐Decorated N‐Doped Carbon as Composite Support