Carbon‐Supported Base Metal Nanoparticles: Cellulose at Work

Hoekstra, Jacco; Versluijs-Helder, Marjan; Vlietstra, Edward J.; Geus, J.W.; Jenneskens, Leonardus W.

doi:10.1002/cssc.201403364

Cited by 29 publications

(45 citation statements)

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“…T = 800°C for nickel nanoparticles with an average diameter of 30 nm, which is close to the 40 nm found in our case. 33 The TEM image ( Figure 4C) clearly shows the origin of the graphite reflection in the XRD pattern. Close to the nickel particle (top right, indicated with an arrow), a ribbon is observed.…”

Section: Resultsmentioning

confidence: 97%

“…With TD-XRD, it was found that the nickel salt became reduced below T = 500°C. 33 Around T = 800°C, a weak reflection in the XRD pattern is observed at 2θ = 30.2°a ttributed to d(002) of graphite ( Figure 3) with an interlayer spacing of 3.44 Å (calculated using Bragg's law, eq 1, Materials and Methods). This interlayer spacing is significantly smaller than that of the original amorphous carbon bodies derived from The Journal of Physical Chemistry C Article pristine MCC (3.83 Å, vide supra).…”

Section: Resultsmentioning

confidence: 99%

“…The Fe 3 O 4 nanoparticles are then stepwise reduced via FeO to bcc Fe(0). 33 Immediate recrystallization of the carbon support upon the final reduction step then occurs (ca. T = 715°C) as observed with the appearance of the d(002) graphitic peak at 2θ = 30.2°with TD-XRD ( Figure 9).…”

Section: Resultsmentioning

confidence: 99%

“…33 It is shown that the amorphous carbonaceous support material obtained from the pyrolysis of MCC is converted to turbostratic graphitic carbon with a ribbon morphology under the influence of nickel, cobalt, and, especially, iron. Copper is found to be completely inactive.…”

Section: Discussionmentioning

confidence: 99%

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Base Metal Catalyzed Graphitization of Cellulose: A Combined Raman Spectroscopy, Temperature-Dependent X-ray Diffraction and High-Resolution Transmission Electron Microscopy Study

et al. 2015

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Microcrystalline cellulose (MCC) spheres homogeneously loaded with the nitrate salts of copper, nickel, cobalt, or iron are excellent model systems to establish the temperature at which highly dispersed base metal nanoparticles are formed as well as to establish the temperature at which catalytic graphitization occurs during pyrolysis in the temperature regime T = 500−800°C. Temperature-dependent X-ray diffraction (TD-XRD) and high-resolution transmission electron microscopy (HRTEM) showed that the base metal nanoparticles are smoothly formed from related base metal oxides via carbothermal reduction (fcc copper, T < 500°C; fcc nickel, T < 500°C; fcc cobalt, T = 570°C; bcc iron, T = 700°C). Moreover, it is shown that at distinct temperatures nickel (T ≥ 800°C), cobalt (T ≥ 800°C), and iron (T ≥ 715°C) nanoparticles catalyze the conversion of the amorphous carbon support into ribbons of turbostratic graphitic carbon according to Raman spectroscopy and TD-XRD. Copper, however, was found to be inactive. Furthermore, HRTEM revealed that nickel (500°C ≤ T < 800°C) and cobalt nanoparticles (700°C ≤ T < 800°C) after their initial formation become encapsulated by graphite-like shells prior to the onset of catalytic graphitization. This does not occur in the presence of iron nanoparticles. This distinction is attributed to the temperature required to access iron nanoparticles by carbothermal reduction and their concomitant mobility. Evidence (HRTEM) is provided that for the onset of catalytic graphitization nickel and cobalt nanoparticles first have to escape from their graphite-like shells. Therefore, iron nanoparticles are the most active catalyst. Our results further show that (metastable) metal carbides play a pivotal role in catalytic graphitization. This is demonstrated by the inactivity of copper nanoparticles, the distinct onset temperatures of catalytic graphitization, and the identification of cementite in the case of iron nanoparticles.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Base Metal Catalyzed Graphitization of Cellulose: A Combined Raman Spectroscopy, Temperature-Dependent X-ray Diffraction and High-Resolution Transmission Electron Microscopy Study

et al. 2015

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“…22 Reduction of base metal (copper, nickel, cobalt, iron) oxides, however, cannot be achieved. 27 Here we investigate the reduction of base metal salts with the carbonaceous material from the CCS spheres, thereby circumventing the use of an external reducing agent. Alternatively, an external H 2 (g) source can be used as the reducing agent.…”

Section: Introductionmentioning

confidence: 99%

Shell decoration of hydrothermally obtained colloidal carbon spheres with base metal nanoparticles

et al. 2015

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The preparation of base metal nanoparticles supported on the shell of colloidal carbon spheres (CCS) is reported. Hydrothermal treatment of a sucrose solution gave conglomerates of ca. 30 mm of CCS (diameter 2-8 mm), which consist of a hydrophobic core with a hydrophilic shell due to the presence of oxygen containing functional groups. The CCS were loaded by wet impregnation with various metal salts (copper, nickel, cobalt, iron). Subsequent pyrolysis under inert conditions at T = 800 1C led to the carbothermal reduction of the impregnated metal salts by the support material. The base metal nanoparticles (size ca. 35-70 nm) are supported on the circumference of the CCS in line with its core-shell structure. Moreover, in the case of nickel, cobalt and iron nanoparticles, all capable of forming metastable metal carbides, the carbonised shells are converted into nanostructures of graphitic carbon, viz., catalytic graphitisation occurs. The spheres were characterised by scanning-and transmission electron microscopy, X-ray diffraction, Raman spectroscopy, elemental analysis, infrared spectroscopy and thermogravimetric analysis. † Electronic supplementary information (ESI) available: Fig. S1; FT-IR spectrum of the CCS after work-up. 63 Fig. S2; Ellingham diagrams of the carbothermal reduction of the base metal oxides: copper (a), nickel (b), cobalt (c) and iron (d). Fig. S3; the original CCS (left) and the CCS after pyrolysis at T = 800 1C (right) in a biphasic system of water/hexane. Fig. S4; deconvolution results of the first-order (a) and second-order (b) Raman spectrum of the CCS after pyrolysis at T = 800 1C (* = N 2 ). Fig. S5; TGA (air) of CCS-supported base metal nanoparticles after pyrolysis at T = 800 1C. Fig. S6; Raman spectra of CCS loaded with copper (a), nickel (b) and cobalt (c) after pyrolysis at T = 800 1C (* = N 2 ). Table S1; elemental analysis and atomic ratios of sucrose and CCS samples. Table S2; deconvolution results of the Raman spectra of the CCS samples loaded with base metal nanoparticles after pyrolysis at T = 800 1C. See

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Precise molecular sieving using metal‐doped ultramicroporous carbon membranes for H₂ separation

Zhao,

Wang,

Fang

et al. 2024

AIChE Journal

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Blue hydrogen produced from fossil fuels is recognized as a promising large‐scale technology for realizing the hydrogen economy. Membrane‐based separation is emerging as a viable alternative to traditional hydrogen purification technologies. Here, we present a facile strategy for fabricating carbon molecular sieve (CMS) hollow fiber membranes containing uniformly dispersed palladium (Pd) nanoparticles. The Pd nanoparticles, anchored in the carbon strands of CMS membranes, induced the carbon matrix toward a more ordered structure arrangement through a synergistic effect of entropy‐driven size exclusion and acceleration of graphitization. As a result, the doped Pd nanoparticles facilitated the formation of ultramicropores <3.3 Å in the CMS membranes, which enabled a precise molecular sieving ability between H2 and CO2 with H2/CO2 selectivity up to 247. Furthermore, the membrane presented good mixed gas separation performances and was stable for over 250 h under simulated harsh industrial conditions.

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Carbon‐Supported Base Metal Nanoparticles: Cellulose at Work

Cited by 29 publications

References 50 publications

Base Metal Catalyzed Graphitization of Cellulose: A Combined Raman Spectroscopy, Temperature-Dependent X-ray Diffraction and High-Resolution Transmission Electron Microscopy Study

Base Metal Catalyzed Graphitization of Cellulose: A Combined Raman Spectroscopy, Temperature-Dependent X-ray Diffraction and High-Resolution Transmission Electron Microscopy Study

Shell decoration of hydrothermally obtained colloidal carbon spheres with base metal nanoparticles

Precise molecular sieving using metal‐doped ultramicroporous carbon membranes for H₂ separation

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Carbon‐Supported Base Metal Nanoparticles: Cellulose at Work

Cited by 29 publications

References 50 publications

Base Metal Catalyzed Graphitization of Cellulose: A Combined Raman Spectroscopy, Temperature-Dependent X-ray Diffraction and High-Resolution Transmission Electron Microscopy Study

Base Metal Catalyzed Graphitization of Cellulose: A Combined Raman Spectroscopy, Temperature-Dependent X-ray Diffraction and High-Resolution Transmission Electron Microscopy Study

Shell decoration of hydrothermally obtained colloidal carbon spheres with base metal nanoparticles

Precise molecular sieving using metal‐doped ultramicroporous carbon membranes for H2 separation

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Product

Resources

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Precise molecular sieving using metal‐doped ultramicroporous carbon membranes for H₂ separation