TY - JOUR
T1 - Adsorption Mechanism and Characteristic Temperatures of the Monolayer Adsorption of CO2 on Graphite
T2 - The Role of Graphene Dimensions
AU - Castaño Plaza, Octavio
AU - Loi, Quang K.
AU - Herrera Diaz, Luis F.
AU - Do, Duong D.
N1 - Publisher Copyright:
© 2024 American Chemical Society.
PY - 2024/7/16
Y1 - 2024/7/16
N2 - Although simulation results for gaseous adsorption on a surface of infinite extent, modeled with periodic conditions at the boundaries of the simulation box, agree with experimental data at high temperatures, simulated isotherms at temperatures below the triple point temperature show unphysical substeps because of the compromise of interactions within the box and interactions between the box and its mirror image boxes. This has been alleviated with surfaces of finite dimensions ( Loi, Q. K. ; Colloids Surf., A 2021, 622, 126690 and Castaño Plaza, O. ; Langmuir 2023, 39 (21), 7456-7468 ) to account for free boundaries at the adsorbate patch on the surface, and the critical parameter of this model substrate is the size of the finite surface. If it is too small, the adsorbate patch does not model the physical reality; however, if it is too large, the computation time is excessive, making the simulation impractical. In this study, we used carbon dioxide/graphite as the model system to explore the effects of finite dimensions on the description of experimental data of Terlain, A. ; Larher, Y. Surf. Sci. 1983, 125 (1), 304-311 , especially for temperatures below the bulk triple point temperature. With the appropriate choice of graphene size, we derived the 2D triple point and 2D critical point temperatures of the monolayer, and most importantly, for temperatures below the 2D critical point temperature, the adsorption mechanism for the formation of the monolayer is due to the interplay between the boundary growth process and the vacancy filling. The extent of this interplay is found to depend on the fractional coverage of the surface.
AB - Although simulation results for gaseous adsorption on a surface of infinite extent, modeled with periodic conditions at the boundaries of the simulation box, agree with experimental data at high temperatures, simulated isotherms at temperatures below the triple point temperature show unphysical substeps because of the compromise of interactions within the box and interactions between the box and its mirror image boxes. This has been alleviated with surfaces of finite dimensions ( Loi, Q. K. ; Colloids Surf., A 2021, 622, 126690 and Castaño Plaza, O. ; Langmuir 2023, 39 (21), 7456-7468 ) to account for free boundaries at the adsorbate patch on the surface, and the critical parameter of this model substrate is the size of the finite surface. If it is too small, the adsorbate patch does not model the physical reality; however, if it is too large, the computation time is excessive, making the simulation impractical. In this study, we used carbon dioxide/graphite as the model system to explore the effects of finite dimensions on the description of experimental data of Terlain, A. ; Larher, Y. Surf. Sci. 1983, 125 (1), 304-311 , especially for temperatures below the bulk triple point temperature. With the appropriate choice of graphene size, we derived the 2D triple point and 2D critical point temperatures of the monolayer, and most importantly, for temperatures below the 2D critical point temperature, the adsorption mechanism for the formation of the monolayer is due to the interplay between the boundary growth process and the vacancy filling. The extent of this interplay is found to depend on the fractional coverage of the surface.
UR - http://www.scopus.com/inward/record.url?scp=85198156323&partnerID=8YFLogxK
U2 - 10.1021/acs.langmuir.4c01428
DO - 10.1021/acs.langmuir.4c01428
M3 - Article
AN - SCOPUS:85198156323
SN - 0743-7463
VL - 40
SP - 14570
EP - 14582
JO - Langmuir
JF - Langmuir
IS - 28
ER -