Professor Caetano Miranda

@workingpaper{2023arXiv230709965M,

title = {Water adsorption in ultrathin silica nanotubes},

author = {Henrique Musseli Cezar and Caetano R. Miranda},

url = {https://arxiv.org/abs/2307.09965},

doi = {10.48550/arXiv.2307.09965},

year  = {2023},

date = {2023-07-01},

urldate = {2023-07-01},

journal = {arXiv e-prints},

pages = {arXiv:2307.09965},

abstract = {Silica (SiO2) nanotubes (NTs) are used in a wide range of applications that go from sensors to nanofluidics. Currently, these NTs can be grown with diameters as small as 3 nm, with walls 1.5 nm thick. Recent experimental advances combined with first-principles calculations suggest that silica NTs could be obtained from a single silica sheet. In this work, we explore the water adsorption in such ultrathin silica NTs using molecular simulation and first-principles calculations. Combining molecular dynamics and density functional theory calculations we obtain putative structures for NTs formed by 10, 12, and 15-membered SiO2 rings. Water adsorption isotherms for these NTs are obtained using Grand Canonical Monte Carlo simulations. Computing the accessible cross-section area (Afree) for the NTs, we were able to understand how this property correlates with condensation pressures. We found that Afree does not necessarily grow with the NT size and that the higher the confinement (smaller Afree), the larger the condensation pressure.},

keywords = {Condensed Matter - Mesoscale and Nanoscale Physics},

pubstate = {published},

tppubtype = {workingpaper}

}

@workingpaper{2023arXiv230711710M,

title = {Revisiting greenhouse gases adsorption in carbon nanostructures: advances through a combined first-principles and molecular simulation approach},

author = {Henrique Musseli Cezar and Teresa Duarte Lanna and Daniela Andrade Damasceno and Alexsandro Kirch and Caetano R. Miranda},

url = {https://arxiv.org/abs/2307.11710},

doi = {10.48550/arXiv.2307.11710},

year  = {2023},

date = {2023-07-01},

urldate = {2023-07-01},

journal = {arXiv e-prints},

pages = {arXiv:2307.11710},

abstract = {Carbon nanotubes and graphene are promising nanomaterials to improve the performance of current gas separation membrane technologies. From the molecular modeling perspective, an accurate description of the interfacial interactions is mandatory to understand the gas selectivity in these materials. Most of the molecular dynamics simulations studies considered available force fields with the standard Lorentz-Berthelot (LB) mixing rules to describe the interaction among carbon dioxide (CO2), methane (CH4) and carbon structures. We performed a systematic study in which we showed the LB underestimates the fluid/solid interaction energies compared to the density functional theory (DFT) calculation results. To improve the classical description, we propose a new parametrization for the cross-terms of the Lenard-Jones (LJ) potential by fitting DFT forces and energies. The obtained model enhanced fluid/carbon interface description showed excellent transferability between single-walled carbon nanotubes (SWCNTs) and graphene. To investigate the effect of the new parametrization on the gas structuring within the SWCNTs with varying diameters, we performed Grand Canonical Monte Carlo (GCMC) simulations. We observed considerable differences in the CO2 and CH4 density within SWCNTs compared to those obtained with the standard approach. Our study highlights the importance of going beyond the traditional Lorentz-Berthelot mixing rules in the studies involving solid/fluid interfaces of confined systems.

},

keywords = {Condensed Matter - Mesoscale and Nanoscale Physics},

pubstate = {published},

tppubtype = {workingpaper}

}