Publications de Guangwei He | EPFL Graph Search

Influence Of Span-Wise Coherence In A Cylinder Wake On The Acoustic Radiations

In the present work the influence of the spanwise coherence of the flow structures on the acoustic emission in the case of cylinder wakes is investigated. For this purpose, the correlation between pressure fluctuations in the far field and velocity fluctua ...

International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics2022

Sodium Superionic Conductors (NASICONs) as Cathode Materials for Sodium-Ion Batteries

Minmin Liu, Guangwei He, Kangning Zhao

Sodium-ion batteries (SIBs) have developed rapidly owing to the high natural abundance, wide distribution, and low cost of sodium. Among the various materials used in SIBs, sodium superion conductor (NASICON)-based electrode materials with remarkable struc ...

SPRINGERNATURE2021

Multipulsed Millisecond Ozone Gasification for Predictable Tuning of Nucleation and Nucleation-Decoupled Nanopore Expansion in Graphene for Carbon Capture

Mounir Driss Mensi, Kumar Varoon Agrawal, Shiqi Huang, Guangwei He, Mostapha Dakhchoune, Luis Francisco Villalobos Vazquez de la Parra, Heng-Yu Chi, Wan-Chi Lee, Kuang-Jung Hsu

Predictable and tunable etching of angstrom-scale nanopores in single-layer graphene (SLG) can allow one to realize high-performance gas separation even from similar-sized molecules. We advance toward this goal by developing two etching regimes for SLG whe ...

2021

Centimeter-scale gas-sieving nanoporous single-layer graphene membrane

Luc Sébastien Bondaz, Kumar Varoon Agrawal, Shiqi Huang, Guangwei He, Mostapha Dakhchoune, Wan-Chi Lee

High-permeance, molecular-sieving, nanoporous single-layer graphene (NSLG) membranes are highly promising for gas separation. However, the formation of cracks during the transfer of NSLG to a low-cost porous support is difficult to avoid. These cracks are ...

2020

Hybrid membranes for energy-efficient carbon capture

Kumar Varoon Agrawal, Guangwei He

Gas separation membrane comprising a porous support onto which is deposited a nanoporous single-layer graphene film with a CO2-philic polymer film having a thickness of 5-100 nm coated on top of graphene nanopores, acting as a CO2-selective film, wherein t ...

2020

Polybenzimidazole copolymer derived lacey carbon film for graphene transfer and contamination removal strategies for imaging graphene nanopores

Kumar Varoon Agrawal, Shiqi Huang, Guangwei He, Mostapha Dakhchoune, Luis Francisco Villalobos Vazquez de la Parra, Wan-Chi Lee

The study of the nanometer-scale vacancy defects (nanopores) in graphene by transmission electron microscopy (TEM) is severely hindered by the presence of polymeric residues originating from the graphene-transfer-step to the TEM grid. The state-of-the-art ...

2020

Two-dimensional nanochannel membranes for molecular and ionic separations

Yifan Li, Guangwei He, Zheyu Jiang, Shaoyu Wang

Two-dimensional (2D) nanosheets have emerged as promising functional materials owing to their atomic thickness and unique physical/chemical properties. By using 2D nanosheets as building blocks, diverse kinds of two-dimensional nanochannel membranes (2DNCM ...

Royal Society of Chemistry2020

Synergistic CO2-Sieving from Polymer with Intrinsic Microporosity Masking Nanoporous Single-Layer Graphene

Mounir Driss Mensi, Kumar Varoon Agrawal, Shiqi Huang, Guangwei He, Jing Zhao, Luis Francisco Villalobos Vazquez de la Parra, Wan-Chi Lee

High-flux nanoporous single-layer graphene membranes are highly promising for energy-efficient gas separation. Herein, in the context of carbon capture, a remarkable enhancement in the CO(2)selectivity is demonstrated by uniquely masking nanoporous single- ...

WILEY-V C H VERLAG GMBH2020

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

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

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

Crystal Engineering of Metal-Organic Framework Thin Films for Gas Separations

Deepu Joseph Babu, Kumar Varoon Agrawal, Guangwei He, Luis Francisco Villalobos Vazquez de la Parra

Metal organic frameworks or MOFs have witnessed a phenomenal rise owing to a highly tunable synthetic chemistry allowing flexibility in the selection of its constituents, namely metal nodes and linkers. Combined with their superior adsorption and diffusion ...

AMER CHEMICAL SOC2019

Electrophoretic Crystallization of Ultrathin High-performance Metal-organic Framework Membranes

Deepu Joseph Babu, Kumar Varoon Agrawal, Guangwei He

We report the synthesis of thin, highly intergrown, polycrystalline metal-organic framework (MOF) membranes on a wide range of unmodified porous and non-porous supports (polymer, ceramic, metal, carbon, and graphene). We developed a novel crystallization t ...

JOURNAL OF VISUALIZED EXPERIMENTS2018

Electrophoretic Nuclei Assembly for Crystallization of High Performance Membranes on Unmodified Supports

Kumar Varoon Agrawal, Shiqi Huang, Guangwei He, Mostapha Dakhchoune, Jing Zhao

Metal-organic frameworks (MOFs) films have recently emerged as highly permselective membranes yielding orders of magnitude higher gas permeance than that from the conventional membranes. However, synthesis of highly-intergrown, ultrathin MOF films on porou ...

2018

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

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

Ultrahigh flux gas-selective nanoporous carbon membrane and manufacturing method thereof

Nikunj Dudani, Kumar Varoon Agrawal, Shiqi Huang, Guangwei He, Mostapha Dakhchoune

The present relates to a nanoporous carbon membrane manufacturing method comprising coating a block copolymer film with hydrophilic and hydrophobic blocks, on a sacrificial non-porous substrate so as to prepare an block copolymer film coated foil, transfer ...

2018