Adding a micropore framework to a parent activated carbon by carbon deposition from methane or ethylene

Ramirez, S. K.; Ferreira, David; Gottberg, V.; Labady, M.; Albornoz, Alberto; Laine, J.

doi:10.1016/s0008-6223(03)00287-2

Cited by 44 publications

(6 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The overall reaction pathway would involve the adsorption and cracking of methane and CO 2 adsorption to react with carbon deposits as suggested by Xiao et al [20]. The present results are also in agreement with Laine et al [21] whom reported the addition of a micropore framework to a parent Nisupported activated carbon catalyst by carbon deposits formed from methane and ethylene decomposition.…”

Section: Texture and Crystalline Phase Characterizationsupporting

confidence: 91%

“…This distribution could be formed from the fragmentation of nickel particles along the filament growth, with the concomitant formation of smaller crystallites. This fragmentation has been attributed to the appearance of various forces influenced by the specific physical and chemical properties of the support [21,22]. Finally, a HR-TEM study was carried out for the Ni-Ca/AC catalyst after 90min reaction.…”

Section: Carbon Deposits and Morphologymentioning

confidence: 99%

See 1 more Smart Citation

Changes on Texture and Crystalline Phase of Activated Carbon-Supported Ni-Ca Catalyst During Dry Methane Reforming

Matos¹,

Rosales²,

González³

et al. 2010

TOMSJ

View full text Add to dashboard Cite

Changes on texture and crystalline phase of AC-supported Ni-Ca catalyst during dry methane reforming were verified. Characterization by N 2 adsorption, XPS, XRD, TEM and HR-TEM was performed. XPS and XRD analysis suggest that the initial activity can be attributed to a nickel reduced phase formed during helium pre-treatment. TEM showed that a homogeneous distribution of Ni nanoparticles between 10-20nm at the tip of multi-walled carbon nanotubes is formed during reaction. HR-TEM showed diffusion of Ni nanoparticles and the formation of carbon-like nano onions with an interlayer separation of 0.5nm suggesting the formation of a ultra-microporous carbon structure. An increase in surface area from 231m 2 .g -1 to 2405m 2 .g -1 after 90min reaction was found and attributed to an in situ activation of carbon deposits by CO 2 gasification. The present results suggest that introducing CO 2 pulses during reaction carbon-supported Ni-Ca could be employed as potential catalysts for methane and other hydrocarbon reforming reactions at mild experimental conditions.

show abstract

Section: Texture and Crystalline Phase Characterizationsupporting

confidence: 91%

Section: Carbon Deposits and Morphologymentioning

confidence: 99%

Changes on Texture and Crystalline Phase of Activated Carbon-Supported Ni-Ca Catalyst During Dry Methane Reforming

Matos¹,

Rosales²,

González³

et al. 2010

TOMSJ

View full text Add to dashboard Cite

show abstract

“…The C1s HRXPS spectra for CoPc/900, Co–N–C/900, Co–N–C/900-30, and Co–N–C/900-50 are depicted in Figure S7a–e and the individual contributions are given in Table S4. In general, the peak position suggests the chemical interaction between the host and heteroatoms present in the matrix, whereas the FWHM qualitatively indicates the presence of disorder in the crystalline carbon matrix and its electrochemical nature. , The C1s HRXPS spectra suggest an asymmetric nature, indicating the prominent presence of sp 2 carbon. The deconvolution indicates the presence of several peaks owing to various carbon moieties.…”

Section: Resultsmentioning

confidence: 99%

“…30,56 The comparatively larger/smaller FWHM imparts the electronwithdrawing/-donating nature in the carbon basal plane. 56 In metal−nitrogen coordinated systems, where the metal redox (M II /M III ) potential plays a significant role in ORR facilitation, 27 the change in the electron-withdrawing/donating nature of the hosting matrix may influence the redox potential of central metal atoms and subsequently the ORR activity. The careful deconvolution of HRXPS C1s spectra indicates that the FWHM of the characteristic sp 2 carbon peak is 1.3 eV for Co−N−C/900, which is larger than that for CoPc/900 (1.16 eV).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Rational Designing of Co–N–C Electrocatalysts for Comprehensive Elucidation of Intrinsic and Extrinsic Activities in the Oxygen Reduction Reaction

Bisen

Nandan

Raj

et al. 2022

ACS Appl. Energy Mater.

View full text Add to dashboard Cite

The catalytic efficacy of an electrocatalyst is mostly apprised by the intrinsic activity of individual active sites and/or by extrinsic activity, which is dependent on the active site density. In oxygen electrochemistry, extrinsic activity can influence the concomitant current density, while intrinsic activity can potentially influence the onset potential, exchange current density, and half-wave potential besides the current density. Modulation of intrinsic activity is mostly limited as it is mainly dependent on the electronic and chemical structure of active sites. The extrinsic activity can be improved by employing the post-synthesis modifications without disturbing the inherent catalytic nature (i.e., intrinsic activity) of individual active sites to ensure the utility of maximum instituted centers. In this work, we have made an attempt to elucidate the intrinsic and extrinsic activities of Co–N–C-based nanostructures to promote the oxygen reduction reaction (ORR) efficiency, which is further elucidated by X-ray absorption spectroscopic studies. The experimental finding suggests that an increase in the N content (∼9 at %) in the host medium, that is, carbon, decisively impacts the intrinsic nature of electrocatalysts with a positive shift in the ORR onset potential of ∼ 131 mV and a nearly 1.5-fold increase in the exchange current density, a matrix that gives a measure of the ability to support catalytic activity inherently. The targeted removal of electrochemically less effective Co nanoparticles (which block/obscure the active centers Co–N x in their vicinity) ensures the structural intactness as the C 1s full width at half maximum of the host matrix along with ORR onset potentials and Tafel slopes remains unchanged. The experimental finding further indicates that the current density can be improved by a factor of 2.6 (i.e., from 2.13 to 5.65 mA/cm2), ensuring the effective utilization of electrocatalysts. Overall, the rational combination of intrinsic and extrinsic activities can be valuable to design a variety of transition metal-carbon based electrocatalysts for diverse electrochemical energy devices.

show abstract

“…6a, the silica monolith exhibited type IV isotherm with H1 hysteresis loop, which was the characteristic of capillary condensation in mesoporous channels [30]. The adsorption-desorption isotherms of hierarchical ZSM-5 catalyst HZC-1 were type II isotherms with H3 hysteresis loop, indicating the presence of extra mesoporosity.…”

Section: Catalyst Characterizationmentioning

confidence: 93%

The Synthesis of Novel Hierarchical Zeolites and Their Performances in Cracking Large Molecules

Zhao

Tong

et al. 2010

Catal Lett

View full text Add to dashboard Cite

Novel hierarchical zeolites with continuous micrometer-scale macropores and mesopores other than popular nanometer-scale mesopores and micropores were synthesized by transforming the skeletons of the silica monolith into zeolites through both the steam-assisted conversion and nanocasting methods. Results showed the novel hierarchical zeolites exhibited high catalytic activity for catalytic cracking large molecules.

show abstract

Adding a micropore framework to a parent activated carbon by carbon deposition from methane or ethylene

Cited by 44 publications

References 3 publications

Changes on Texture and Crystalline Phase of Activated Carbon-Supported Ni-Ca Catalyst During Dry Methane Reforming

Changes on Texture and Crystalline Phase of Activated Carbon-Supported Ni-Ca Catalyst During Dry Methane Reforming

Rational Designing of Co–N–C Electrocatalysts for Comprehensive Elucidation of Intrinsic and Extrinsic Activities in the Oxygen Reduction Reaction

The Synthesis of Novel Hierarchical Zeolites and Their Performances in Cracking Large Molecules

Contact Info

Product

Resources

About