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Gas transport across carbon nitride nanopores: a comparison of van der Waals functionals against the random-phase approximation

Mohammad Tohidi Vahdat1,2*, Davide Campi2,3*, Nicola Colonna2,4*, Nicola Marzari2*, Kumar Agrawal Varoon1*

1 Laboratory of Advanced Separations (LAS), École Polytechnique Fédérale de Lausanne (EPFL), Switzerland

2 Theory and Simulation of Materials (THEOS) and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), EPFL, Lausanne, Switzerland

3 Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi 55, I-20125 Milano, Italy

4 Laboratory for Neutron Scattering and Imaging (LSN), Paul Scherrer Institute, 5232 Villigen PSI, Switzerland

* Corresponding authors emails: mohammad.vahdat@epfl.ch, davide.campi@epfl.unimib.it, nicola.colonna@psi.ch, nicola.marzari@epfl.ch, kumar.agrawal@epfl.ch
DOI10.24435/materialscloud:pn-w9 [version v1]

Publication date: Sep 07, 2021

How to cite this record

Mohammad Tohidi Vahdat, Davide Campi, Nicola Colonna, Nicola Marzari, Kumar Agrawal Varoon, Gas transport across carbon nitride nanopores: a comparison of van der Waals functionals against the random-phase approximation, Materials Cloud Archive 2021.146 (2021), doi: 10.24435/materialscloud:pn-w9.


C2N is an ordered two-dimensional carbon nitride with a high density (1.7 × 10^14 cm−2) of 3.1 Å-sized nanopores, making it promising for high-flux gas sieving for energy-efficient He and H2 purification. Herein, we discuss the accurate calculation of potential energy surfaces for He, H2, N2, and CO2 across C2N nanopores, to characterize the gas-sieving potential of C2N. We compare the potential energy surface derived from density-functional theory calculations using five commonly used van der Waals (vdW) approximations. While all five functionals point that the C2N nanopore yields He/N2 and H2/N2 selectivities over 1000, adsorption energies and energy barriers vary remarkably depending on the approximation chosen. To make progress, we compare the calculations against the results from the adiabatic connection fluctuation dissipation theory, with random-phase approximation, known to be accurate in capturing vdW interactions. The comparison indicates that the interaction energy is less accurate with vdW density functional theory. On the other hand, more empirical corrections work reasonably well, a finding that we also confirm for another carbon nitride lattice, poly(triazine imide). Overall, we recommend these for screening carbon nitride materials for gas separation, but also comparing functionals with higher-order approaches when dealing with different materials.

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205.3 MiB This folder includes all the DFT and RPA calculations


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carbon nitrides nanoscale transport density-functional theory random phase approximation van-der-Waals approximations MARVEL EPFL SNSF CSCS

Version history:

2021.146 (version v1) [This version] Sep 07, 2021 DOI10.24435/materialscloud:pn-w9