Characterization of the chemical interaction between single-walled carbon nanotubes and titanium dioxide nanoparticles by thermogravimetric analyses and resonance Raman spectroscopy

Silva, Karina C.; Cório, Paola; Santos, Jonnatan J.

doi:10.1016/j.vibspec.2016.06.012

Cited by 17 publications

(6 citation statements)

References 35 publications

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“…It has been reported that the intensity of the D band relative to the G band can be used as a qualitative measure of the formation of different kinds of carbon with different degree of graphitization or disorder in the carbon structure [78][79][80]. Smaller I D /I G values indicate higher crystallinity due to higher contribution of the graphitic carbon structures formed [81,82] but it also implies more layers constituting the deposited carbon [83]. In these sense, the estimated values are summarized also in Figure 12 These results indicate that carbon deposition over the Co-Cu/SBA-15 sample occurs in larger extent on the Co surface when compared with the other samples, leading to the growth of well-ordered carbon, which may be responsible of catalyst deactivation since it act as a shell covering the active Co sites layer by layer [80].…”

Section: Catalytic Testsmentioning

confidence: 99%

Hydrogen Production from Steam Reforming of Acetic Acid as a Model Compound of the Aqueous Fraction of Microalgae HTL Using Co-M/SBA-15 (M: Cu, Ag, Ce, Cr) Catalysts

et al. 2019

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Hydrogen production derived from thermochemical processing of biomass is becoming an interesting alternative to conventional routes using fossil fuels. In this sense, steam reforming of the aqueous fraction of microalgae hydrothermal liquefaction (HTL) is a promising option for renewable hydrogen production. Since the HTL aqueous fraction is a complex mixture, acetic acid has been chosen as model compound. This work studies the modification of Co/SBA-15 catalyst incorporating a second metal leading to Co-M/SBA-15 (M: Cu, Ag, Ce and Cr). All catalysts were characterized by N2 physisorption, ICP-AES, XRD, TEM, H2-TPR, H2-TPD and Raman spectroscopy. The characterization results evidenced that Cu and Ag incorporation decreased the cobalt oxides reduction temperatures, while Cr addition led to smaller Co0 crystallites better dispersed on the support. Catalytic tests done at 600 °C, showed that Co-Cr/SBA-15 sample gave hydrogen selectivity values above 70 mol % with a significant reduction in coke deposition.

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Section: Catalytic Testsmentioning

confidence: 99%

Hydrogen Production from Steam Reforming of Acetic Acid as a Model Compound of the Aqueous Fraction of Microalgae HTL Using Co-M/SBA-15 (M: Cu, Ag, Ce, Cr) Catalysts

et al. 2019

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“…The vibrational spectroscopy has been contributing largely in many fields of materials science because of its versatility of non-destructive sampling methods 1 . Raman spectroscopy is a technique which has been broadly used to characterize diamond-like carbon (DLC) films, graphite and graphene films [2][3][4][5][6][7][8] . It has also been applied to detect stress in semiconductor films like Si and SiC, in ZrO and Cr 2 O 3 films which are oxidized at high temperatures and also carbon and bio tissue materials 9 .…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Carbon thin Films Using Raman Spectroscopy

et al. 2018

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Carbon thin films deposited by the magnetron sputtering technique were evaluated by Raman spectroscopy to study the influence on their crystallinity caused by different parameters like the carbon deposition time, the different buffer-layers and substrates employed and also two distinct heat treatments. The present results showed that the choice of these parameters plays an important role in the production of these films. The results also indicate the possibility of using the technique for the production of carbon thin films to be employed in future in applications with controlled content of structural defects, predominance of ordered sp 2 bondings and tendency of graphitization.

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“…The ratio of peaks area between D and G band (I D /I G ) can give information about the graphitization degree of the carbon structures 67,88,89 . The higher I D /I G ratio, the lower graphitization degree 90,91 . Thus, the calculated results are displayed in Figure 17.…”

Section: Resultsmentioning

confidence: 99%

“…67,88,89 The higher I D / I G ratio, the lower graphitization degree. 90,91 Thus, the calculated results are displayed in Figure 17. From the results, the I D /I G ratio increases in the following order: Co-Cu/CaSBA-15<Co/CaSBA-15<Co-Ag/CaSBA-15<Co-Ce/CaSBA-15.…”

Section: Characterization Of Used Catalystsmentioning

confidence: 99%

Effect of the incorporation of reducibility promoters (Cu, Ce, Ag) in Co/ CaSBA ‐15 catalysts for acetic acid steam reforming

et al. 2020

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Summary In this work, we have faced the problem associated with the addition of Ca to Co/SBA‐15, which gave rise to an increase in the dispersion of the particles at the expense of increasing its reduction temperature, thus limiting its reducibility as demonstrated by XPS. This detrimental effect has been solved by the inclusion of reducibility promoters such as Cu, Ag and Ce. All these promoters led to an increase in the acetic acid conversion attributed to their beneficial effect in the catalyst reducibility. With the inclusion of Ce to Co/CaSBA‐15, the high dispersion was maintained while the percentage of reduced Co species increased by ~90% compared with Co/CaSBA‐15, leading to the best catalytic performance (X ~ 99%, YH2 = 71.8%) after 5 hours TOS in the acetic acid steam reforming (S/C = 2) at 600°C using a WHSV = 30.1 hours−1. Furthermore, Co‐Ce/CaSBA‐15 showed good stability with hydrogen yield close to the thermodynamic value. These results highlight the necessity of combining both dispersing additives and promoters of reducibility to enhance the catalytic performance in steam reforming.

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Characterization of the chemical interaction between single-walled carbon nanotubes and titanium dioxide nanoparticles by thermogravimetric analyses and resonance Raman spectroscopy

Cited by 17 publications

References 35 publications

Hydrogen Production from Steam Reforming of Acetic Acid as a Model Compound of the Aqueous Fraction of Microalgae HTL Using Co-M/SBA-15 (M: Cu, Ag, Ce, Cr) Catalysts

Hydrogen Production from Steam Reforming of Acetic Acid as a Model Compound of the Aqueous Fraction of Microalgae HTL Using Co-M/SBA-15 (M: Cu, Ag, Ce, Cr) Catalysts

Evaluation of Carbon thin Films Using Raman Spectroscopy

Effect of the incorporation of reducibility promoters (Cu, Ce, Ag) in Co/ CaSBA ‐15 catalysts for acetic acid steam reforming

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