Publications de Mojtaba Chevalier

Publications associées (12)

Electrochemical-repaired porous graphene membranes for precise ion-ion separation

Kumar Varoon Agrawal, Kangning Zhao, Heng-Yu Chi, Kuang-Jung Hsu, Mojtaba Chevalier, Yueqing Shen, Shuqing Song, Zongyao Zhou

The preparation of atom-thick porous lattice hosting & Aring;-scale pores is attractive to achieve a large ion-ion selectivity in combination with a large ion flux. Graphene film is an ideal selective layer for this if high-precision pores can be incorpora ...

Nature Portfolio2024

Crystallization of Size-Selective Nanopores in Graphene for Gas Separation

Mojtaba Chevalier

Nanoporous single-layer graphene (N-SLG) membranes, owing to their single-atom thinness, have the potential to exceed the permeance and selectivity limits of gas separation membranes. However, two key issues in the top-down N-SLG synthesis need to be addre ...

EPFL2022

Demonstrating and Unraveling a Controlled Nanometer-Scale Expansion of the Vacancy Defects in Graphene by CO2

Kumar Varoon Agrawal, Luis Francisco Villalobos Vazquez de la Parra, Kuang-Jung Hsu, Mojtaba Chevalier

A controlled manipulation of graphene edges and vacancies is desired for molecular separation, sensing and electronics applications. Unfortunately, available etching methods always lead to vacancy nucleation making it challenging to control etching. Herein ...

Wiley-VCH Verlag GmbH2022

Direct synthesis of nanocrystalline single-layer porous graphene for hydrogen sieving

Kumar Varoon Agrawal, Mojtaba Chevalier, Luc Sébastien Bondaz, Jian Hao, Ceren Kocaman

Porous single -layer graphene is promising as the selective layer for membrane-based gas separation thanks to the atomic thickness of the pore which can yield high permselective flux. Direct synthesis of porous graphene by chemical vapor deposition (CVD) i ...

Pergamon-Elsevier Science Ltd2024

Hydrogen-sieving single-layer graphene membranes obtained by crystallographic and morphological optimization of catalytic copper foil

Kumar Varoon Agrawal, Shiqi Huang, Shaoxian Li, Mojtaba Chevalier

Gas separation membranes based on single-layer-graphene are highly attractive because the size of graphene nanopores can be tuned to separate gases by the size-sieving mechanism. A prerequisite for this, the synthesis of high-quality polycrystalline single ...

2020

Structure Evolution of Graphitic Surface upon Oxidation: Insights by Scanning Tunneling Microscopy

Nicola Marzari, Kumar Varoon Agrawal, Mounir Driss Mensi, Shiqi Huang, Shaoxian Li, Kuang-Jung Hsu, Mojtaba Chevalier, Mohammad Tohidivahdat

Oxidation of graphitic materials has been studied for more than a century to synthesize materials such as graphene oxide, nanoporous graphene, and to cut or unzip carbon nanotubes. However, the understanding of the early stages of oxidation is limited to t ...

AMER CHEMICAL SOC2022

Crystallization of gas-selective nanoporous graphene by competitive etching and growth: a modeling study

Kumar Varoon Agrawal, Mojtaba Chevalier

A robust synthesis methodology for crystallizing nanoporous single-layer graphene hosting a high density of size-selective nanopores is urgently needed to realize the true potential of two-dimensional membranes for gas separation. Currently, there are no c ...

Nature Research2019

Single-layer graphene membranes by crack-free transfer for gas mixture separation

Andreas Züttel, Emad Oveisi, Kumar Varoon Agrawal, Duncan Thomas Lindsay Alexander, Wen Luo, Shiqi Huang, Mostapha Dakhchoune, Guangwei He, Mojtaba Chevalier, Jing Zhao

The single-layer graphene film, when incorporated with molecular-sized pores, is predicted to be the ultimate membrane. However, the major bottlenecks have been the crack-free transfer of large-area graphene on a porous support, and the incorporation of mo ...

Nature Publishing Group2018

Tuning Pore Size in Graphene in the Angstrom Regime for Highly Selective Ion-Ion Separation

Kumar Varoon Agrawal, Kangning Zhao, Luis Francisco Villalobos Vazquez de la Parra, Heng-Yu Chi, Shaoxian Li, Kuang-Jung Hsu, Mojtaba Chevalier, Wan-Chi Lee

Zero-dimensional pores spanning only a few angstroms in size in two-dimensional materials such as graphene are some of the most promising systems for designing ion-ion selective membranes. However, the key challenge in the field is that so far a crack-free ...

Amer Chemical Soc2024

Hydrogen sieving from intrinsic defects of benzene-derived single-layer graphene

Kumar Varoon Agrawal, Mostapha Dakhchoune, Shiqi Huang, Mojtaba Chevalier, Jing Zhao, Mina Moradi

Single-layer graphene films, crystallized by chemical vapor deposition, host a low density of vacancy defects that are attractive for the size-sieving of molecules. The size and the density of such defects are a function of the growth temperature and the c ...

2019

High-permeance polymer-functionalized single-layer graphene membranes that surpass the postcombustion carbon capture target

Emad Oveisi, Kumar Varoon Agrawal, Mounir Driss Mensi, Luis Francisco Villalobos Vazquez de la Parra, Shiqi Huang, Guangwei He, Mojtaba Chevalier, Jing Zhao

Membrane-based postcombustion carbon capture can reduce the capture penalty in comparison to absorbent-based separation. To realize this, high-performance membranes are urgently needed with a CO2 permeance exceeding 1000 gas permeation units or GPU, and a ...

2019

Gas-sieving zeolitic membranes fabricated by condensation of precursor nanosheets

Michele Ceriotti, Kumar Varoon Agrawal, Pascal Alexander Schouwink, Luis Francisco Villalobos Vazquez de la Parra, Mostapha Dakhchoune, Claudia Esther Avalos, Mojtaba Chevalier, Rocio Semino Barbaresi

The synthesis of molecular-sieving zeolitic membranes by the assembly of building blocks, avoiding the hydrothermal treatment, is highly desired to improve reproducibility and scalability. Here we report exfoliation of the sodalite precursor RUB-15 into cr ...

2020