The reactions of hydrogen and carbon monoxide with surface-bound oxides on carbon

Sibraa, A.; Newbury, T.; Haynes, Brian S.

doi:10.1016/s0010-2180(99)00110-8

Cited by 9 publications

(10 citation statements)

References 14 publications

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“…8,12 There have been a few studies of CO adsorption on carbonaceous materials such as fullerenes, nanotubes, graphite, and diamond, and it was proposed that CO is weakly physisorbed on these materials. 11,[13][14][15][16] Grand Canonical Monte Carlo (GCMC) simulations have shown that carbon monoxide adsorption inside and outside singlewalled carbon nanotubes depends on pressure, temperature, and sorbent structure, so, under the proper conditions, it is a useful way to separate gas mixtures such as hydrogen and carbon monoxide because the interaction between CO and the tube wall is stronger than that of H 2 .…”

Section: Introductionmentioning

confidence: 99%

A DFT Study of Interaction of Carbon Monoxide with Carbonaceous Materials

et al. 2003

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Reaction of CO with carbonaceous surfaces was investigated using B3LYP density functional theory level (DFT) with the 6-31G(d) basis set. It was found that CO can be adsorbed exothermically on the active sites of zigzag, armchair, and tip carbonaceous models to yield stable intermediates such as cyclic ether, carbonyl, lactone, ketone, carbonate, and semiquinone functionalities. The above reactions are important in carbon gasification processes as well as in carbon single-wall nanotubes formation from CO disproportionation reaction. In the case of gasification, adsorption of CO blocks the active sites of the carbonaceous material and thus can reduce the efficiency of the process. Furthermore, it was found that when CO is adsorbed in a carbonyl type structure (CdCdO), there is a reversible interconversion process by ring closure with a neighbor active site to produce a cyclic ether (furan type), a process that requires an additional neighboring active site. Consequently, the available number of active sites for gasification reaction is decreased and therefore the gasification reaction is inhibited. In addition, CO adsorption on oxidized surfaces can favor CO 2 desorption. Such desorption can be either taking off an oxygen atom that potentially was going to be desorbed as CO or depositing a carbon atom on the surface due to the disproportionation reaction 2 CO ) C + CO 2 . Both effects can inhibit or retard the gasification process. The results from the disproportionation reaction can also provide an insight into the mechanism for carbon single-wall nanotubes growth using CO as precursor.

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Section: Introductionmentioning

confidence: 99%

A DFT Study of Interaction of Carbon Monoxide with Carbonaceous Materials

et al. 2003

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“…These results stimulated further studies of the kinetics of forming surface complexes and the continuous distributions of the activation energies for adsorption and desorption. Recent studies by Du et al [16,36], Brown et al [17], Sibraa et al [18], Haynes [19], Hurt and Haynes [20] and Campbell and Mitchell [21] have shown the activation energies to have Gaussian-like distributions (Fig. 3).…”

Section: Surface Complexes and Activation Energiesmentioning

confidence: 92%

“…3, the obtained distribution was the same for 3 different temperature ramps in the experiments and well fitted by a Gaussian-like function with mean activation energy, E = 292 kJ/mole and standard deviation, r = 30.6 kJ/mole. Experimental results involving different types of graphite have also shown that the distributions of the activation energies are reproducible and independent of temperature and burn-off, but depend on the graphite type [16][17][18][19][20][21]36]. …”

Section: Surface Complexes and Activation Energiesmentioning

confidence: 99%

“…2). The distributions of the activation energies can be measured in desorption experiments in which the controlled temperature of the sample changes linearly with time [16][17][18][19][20][21]36].…”

Section: Surface Complexes and Activation Energiesmentioning

confidence: 99%

“…doi:10.1016/j.jnucmat.2011.01.129 could be measured directly in temperature-controlled desorption experiments [15][16][17][18][19][20][21]. These distributions, which strongly depend on the type of graphite, could also be deduced from the experimental measurements of the gasification rates and/or the yields and ratio of the CO and CO 2 reaction products, using a multiparameter optimization algorithm.…”

Section: Introductionmentioning

confidence: 99%

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