On the anatomy of the adsorption heat versus loading as a function of temperature and adsorbate for a graphitic surface

Do, D.D.; Nicholson, D.; Do, H.D.

doi:10.1016/j.jcis.2008.05.027

Cited by 33 publications

(31 citation statements)

References 44 publications

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“…These temperatures were chosen to show the 2D transitions from the gas-like state to the solid state (60 K) and from the gas-like state to a liquid-like state. The isosteric heat increases linearly with loading up to the 2D-transition, becomes constant across the transition, and then increases approximately linearly after the first transition [44]. At 60 K, after the gas-solid transition but before the sub-step, the isosteric heat decreases because adsorption begins in the second layer.…”

Section: Effects Of Temperature On the 2d Transitionsmentioning

confidence: 95%

On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface

Diao

Fan

et al. 2015

Journal of Colloid and Interface Science

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The adsorption and desorption of Kr on graphite at temperatures in the range 60 K to 88 K, was systematically investigated using a combination of several simulation techniques including: grand canonical Monte Carlo (GCMC), canonical kinetic-Monte Carlo (C-kMC) and the Mid-Density scheme (MDS). Particular emphasis was placed on the gas-solid, gas-liquid and liquid-solid 2D phase transitions. For temperatures below the bulk triple point, the transition from a 2D-liquid-like monolayer to a 2D-solid-like state is manifested as a sub-step in the isotherm. A further increase in the chemical potential leads to another rearrangement of the 2D-solidlike state from a disordered structure to an ordered structure that is signalled by (1) another sub-step in the monolayer region and (2) a spike in the plot of the isosteric heat versus density at loadings close to the dense monolayer coverage concentration. Whenever a 2D transition occurs in a grand canonical isotherm it is always associated with a hysteresis, a feature that is not widely recognized in the literature. We studied in details this hysteresis with the analysis of the canonical isotherm, obtained with C-kMC, which exhibits a van der Waals (vdW) type loop with a vertical segment in the middle. We complemented the hysteresis loop and the vdW curve with the analysis of the equilibrium transition obtained with the MDS, and found that the equilibrium transition coincides exactly with the vertical segment of the C-kMC isotherm, indicating the coexistence of two phases at equilibrium. We also analysed adsorption at higher layers and found that the 2D-coexistence is also observed, provided that the temperature is well below the triple point. Finally the 2D-critical temperatures were obtained for the first three layers and they are in good agreement with the experimental data in the literature.

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Section: Effects Of Temperature On the 2d Transitionsmentioning

confidence: 95%

On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface

Diao

Fan

et al. 2015

Journal of Colloid and Interface Science

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“…The explanation of the heat spike for adsorption of gases on a homogenous graphite surface has been given elsewhere [7]; we briefly described it graphically in Fig. 3:…”

Section: Noble and Non-polar Gases Adsorption On Graphitementioning

confidence: 99%

“…The experimental isosteric heat gives the overall heat released from the process [2][3][4][5][6], and its dependence on the extent of loading can provide insight into how molecules interact with various parts of the system as well with themselves. Together with computer simulation this can give detailed contributions of various interactions: fluid-fluid, fluid-basal plane and fluid-functional group [7,8]. In this paper we presented an interpretation of the experimental heat versus loading, calculated from the adsorption isotherms at different temperatures.…”

Section: Introductionmentioning

confidence: 99%

On the isosteric heat of adsorption of non-polar and polar fluids on highly graphitized carbon black

Horikawa

Zeng

et al. 2015

Journal of Colloid and Interface Science

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“…7. Detailed explanation of these linear regions has been provided by Do and co-workers [8,24]. Readers are referred to these papers for more details.…”

Section: Isosteric Heatmentioning

confidence: 99%

“…Another feature that we observe in this figure is that the linear portions in the submonolayer region are less pronounced as temperature is increased. This is physically expected because of the greater mobility of adsorbed molecules at high temperatures [24], which results in adsorption in multiple layers at the same time rather than layerwise adsorption (i.e., layer by layer). Our GCMC simulation results at 77 K indeed confirm this layer by layer adsorption.…”

Section: Isosteric Heatmentioning

confidence: 99%

Effects of surface mediation on the adsorption isotherm and heat of adsorption of argon on graphitized thermal carbon black

Fan¹,

Birkett²,

Do³

2010

Journal of Colloid and Interface Science

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On the anatomy of the adsorption heat versus loading as a function of temperature and adsorbate for a graphitic surface

Cited by 33 publications

References 44 publications

On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface

On the 2D-transition, hysteresis and thermodynamic equilibrium of Kr adsorption on a graphite surface

On the isosteric heat of adsorption of non-polar and polar fluids on highly graphitized carbon black

Effects of surface mediation on the adsorption isotherm and heat of adsorption of argon on graphitized thermal carbon black

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