Morphological and crystallinity differences in nitrogen-doped carbon nanotubes grown by chemical vapour deposition decomposition of melamine over coal fly ash

Hlekelele, Lerato; Franklyn, Paul J.; Tripathi, P.; Durbach, Shane H.

doi:10.1039/c6ra16858b

Cited by 25 publications

(12 citation statements)

References 41 publications

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“…The description of the synthesis and purication processes of the NCNTs that were used in this study have been described in our previous reports. 19,45 Concisely, a two-stage quartz tube furnace with independent thermocouples and controllers was used for the synthesis of NCNTs. A gram of the carbon and nitrogen source, melamine (Sigma Aldrich), was placed in a quartz boat and placed in the middle of the rst-stage furnace.…”

Section: Synthesis and Purication Of Ncntsmentioning

confidence: 99%

Resin-gel incorporation of high concentrations of W⁶⁺ and Zn²⁺ into TiO₂-anatase crystal to form quaternary mixed-metal oxides: effect on the a lattice parameter and photodegradation efficiency

et al. 2019

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Section: Synthesis and Purication Of Ncntsmentioning

confidence: 99%

Resin-gel incorporation of high concentrations of W⁶⁺ and Zn²⁺ into TiO₂-anatase crystal to form quaternary mixed-metal oxides: effect on the a lattice parameter and photodegradation efficiency

et al. 2019

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“…However, poor surface coverage by nitrogen could result from the thermal decomposition of nitrogen-containing functional groups in the structure of carbon during biomass pyrolysis at high temperatures above 700 °C 31 . Thus, melamine can serve as an additional nitrogen source for nitrogen doping on various carbon supports (e.g., graphene and carbon nanotubes/xerogels) to increase their nitrogen content [32][33][34] . In addition to the functional groups on the catalyst surface, solvents also affect chemical reactivity and selectivity of catalytic reactions [35][36] .…”

Section: Introductionmentioning

confidence: 99%

Selective Glucose Isomerization to Fructose via a Nitrogen-doped Solid Base Catalyst Derived from Spent Coffee Grounds

Chen

Cho

et al. 2018

ACS Sustainable Chem. Eng.

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In this work, glucose isomerization to fructose was conducted via a solid base biochar catalyst derived from spent coffee grounds and melamine. The X-ray photoelectron spectroscopy (XPS) spectra identified the majority of pyridinic nitrogen on the biochar surface, which imparted the strong base character of the catalyst. Activity of the catalyst was evidenced by fast conversion of glucose (12%) and high selectivity to fructose (84%) in 20 min at a moderate temperature (120 °C) compared to recently reported immobilized tertiary amines at comparable N concentrations (10-15 mol% relative to glucose). By increasing the reaction temperature to 160 °C, fructose yield achieved 14% in 5 min. The base biochar catalyst showed superior selectivity (>80%) to commonly used homogeneous base catalysts such as aqueous hydroxides and amines (50-80%) and comparable catalytic activity (~20 mol% conversion within 20 min). Moreover, co-solvent of acetone in the reaction system may increase the overall basicity by stabilizing protonated water clusters via hydrogen bonding, which led to faster conversion and higher fructose selectivity than those in water. Approximately 19% fructose was obtained at 160 °C, and the basic sites on the biochar catalyst were stable in hydrothermal environment as indicated by acid-base titration test. Therefore, nitrogen-doped engineered biochar can potentially serve as solid base catalyst for biorefinery processes.

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“…The NHCSs materials were made by mixing melamine mixed with the solid plastic waste and by then heating the mixture [36]. The melting point of melamine (345 • C) [37] is similar to the decomposition temperature of PP (which melts at 130 • C).…”

Section: Resultsmentioning

confidence: 99%

CVD Synthesis of Solid, Hollow, and Nitrogen-Doped Hollow Carbon Spheres from Polypropylene Waste Materials

Tripathi¹,

Durbach²,

Coville³

2019

Applied Sciences

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Plastic waste leaves a serious environmental footprint on the planet and it is imperative to reduce this. Consequently, recycling has been regarded as an important approach in providing one solution to this problem. In this study, we enhanced the value of polypropylene (PP) plastic waste by using it as a hydrocarbon source to synthesize a variety of spherical carbon nanomaterials. Here, a CVD method was used to decompose the PP initially into a hydrocarbon gas (propylene). Thereafter, PP was employed to synthesize solid carbon spheres (SCSs), hollow carbon spheres (HCSs), and nitrogen-doped hollow carbon spheres (NHCSs). The latter two were made using a silica template while the N-doping was achieved by the addition of melamine to PP. Yields obtained were between 12–20%. The SCSs (d = 800 nm to 1200 nm), HCSs (id = 985 nm; shell width = 35 nm), and NHCSs (id = ca. 1000 nm; shell width = 40 nm) were all characterized by TEM, SEM, TGA, laser Raman spectroscopy, and XPS.

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Morphological and crystallinity differences in nitrogen-doped carbon nanotubes grown by chemical vapour deposition decomposition of melamine over coal fly ash

Abstract: CVD of melamine over waste coal fly ash to form N-doped carbon nanotubes (NCNTs) of various morphologies and crystallinities as a function of temperature and % N incorporation.

Cited by 25 publications

References 41 publications

Resin-gel incorporation of high concentrations of W⁶⁺ and Zn²⁺ into TiO₂-anatase crystal to form quaternary mixed-metal oxides: effect on the a lattice parameter and photodegradation efficiency

Resin-gel incorporation of high concentrations of W⁶⁺ and Zn²⁺ into TiO₂-anatase crystal to form quaternary mixed-metal oxides: effect on the a lattice parameter and photodegradation efficiency

Selective Glucose Isomerization to Fructose via a Nitrogen-doped Solid Base Catalyst Derived from Spent Coffee Grounds

CVD Synthesis of Solid, Hollow, and Nitrogen-Doped Hollow Carbon Spheres from Polypropylene Waste Materials

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Morphological and crystallinity differences in nitrogen-doped carbon nanotubes grown by chemical vapour deposition decomposition of melamine over coal fly ash

Abstract: CVD of melamine over waste coal fly ash to form N-doped carbon nanotubes (NCNTs) of various morphologies and crystallinities as a function of temperature and % N incorporation.

Cited by 25 publications

References 41 publications

Resin-gel incorporation of high concentrations of W6+ and Zn2+ into TiO2-anatase crystal to form quaternary mixed-metal oxides: effect on the a lattice parameter and photodegradation efficiency

Resin-gel incorporation of high concentrations of W6+ and Zn2+ into TiO2-anatase crystal to form quaternary mixed-metal oxides: effect on the a lattice parameter and photodegradation efficiency

Selective Glucose Isomerization to Fructose via a Nitrogen-doped Solid Base Catalyst Derived from Spent Coffee Grounds

CVD Synthesis of Solid, Hollow, and Nitrogen-Doped Hollow Carbon Spheres from Polypropylene Waste Materials

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Resin-gel incorporation of high concentrations of W⁶⁺ and Zn²⁺ into TiO₂-anatase crystal to form quaternary mixed-metal oxides: effect on the a lattice parameter and photodegradation efficiency

Resin-gel incorporation of high concentrations of W⁶⁺ and Zn²⁺ into TiO₂-anatase crystal to form quaternary mixed-metal oxides: effect on the a lattice parameter and photodegradation efficiency