Publications by Heng-Yu Chi | EPFL Graph Search

Non-van-der-Waals Oriented Two-Dimensional UiO-66 Films by Rapid Aqueous Synthesis at Room Temperature

Wendy Lee Queen, Kumar Varoon Agrawal, Kuang-Jung Hsu, Heng-Yu Chi, Shuqing Song, Ranadip Goswami, Kangning Zhao, Qi Liu

The synthesis of MOFs in a two-dimensional (2D) film morphology is attractive for several applications including molecular and ionic separation. However, 2D MOFs have only been reported from structures that crystallize in lamellar morphology, where layers ...

2025

Modulation of Graphene Oxidation Using Substrate-Induced Electron-Hole Puddles for Advancing Molecular Separation

Kumar Varoon Agrawal, Kuang-Jung Hsu, Heng-Yu Chi, Ranadip Goswami, Shiqi Huang

Tuning the reactivity of graphene enables molecular-level engineering of the lattice, achieving desired chemical and structural properties through functionalization, doping, and etching. Atom-thin graphene film hosting Å-scale pores, with capability to dif ...

2025

Angstrom‐Scale Triangular Pore in Single‐Layer Hexagonal Boron Nitride Membrane for Molecular Sieving

Kumar Varoon Agrawal, Heng-Yu Chi, Luis Francisco Villalobos Vazquez de la Parra

Single‐layer crystalline films are ideal separation membrane materials because their atomic thickness could yield the highest possible molecular flux once nanopores are generated. However, the development of single‐layer membranes with well‐defined pore st ...

Wiley2025

Crystal, defect, and morphology engineering of porous two-dimensional materials for ionic separation

Heng-Yu Chi

Ordered two-dimensional (2D) materials hosting Å-scale pores are highly promising for enabling challenging separation, thanks to well-defined pore geometry resulting in tight confinement of ions when hosted inside the pore. In addition, the 2D nature of th ...

EPFL2024

Graphene membranes with pyridinic nitrogen at pore edges for high-performance CO2 capture

Andreas Züttel, Kumar Varoon Agrawal, Kuang-Jung Hsu, Heng-Yu Chi, Marina Micari, Xuekui Duan, Shuqing Song, Luis Francisco Villalobos Vazquez de la Parra, Shiqi Huang, Shaoxian Li

Membranes based on a porous two-dimensional selective layer offer the potential to achieve exceptional performance to improve energy efficiency and reduce the cost for carbon capture. So far, separation from two-dimensional pores has exploited differences ...

Nature Portfolio2024

Advancing Molecular Sieving via Å-Scale Pore Tuning in Bottom-Up Graphene Synthesis

Kumar Varoon Agrawal, Mounir Driss Mensi, Heng-Yu Chi, Cédric Karel J Van Goethem, Kangning Zhao

Porous graphene films are attractive as a gas separation membrane given that the selective layer can be just one atom thick, allowing high-flux separation. A favorable aspect of porous graphene is that the pore size, essentially gaps created by lattice def ...

Amer Chemical Soc2024

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

Kumar Varoon Agrawal, Kuang-Jung Hsu, Heng-Yu Chi, Shuqing Song, Kangning Zhao, 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

High-performance H2/CO2 separation from 4-nm-thick oriented Zn2(benzimidazole)4 films

Kumar Varoon Agrawal, Heng-Yu Chi, Shuqing Song, Ranadip Goswami, Qi Liu, Zongyao Zhou

High-performance membrane-based H2/CO2 separation offers a promising way to reduce the energy costs of precombustion capture. Current membranes, often made from two-dimensional laminates like metal-organic frameworks, have limitations due to complex fabric ...

2024

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

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

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

Development of tuneable polyamine top layer for nanofiltration with high stability in bleach and at extreme pHs

Kumar Varoon Agrawal, Heng-Yu Chi, Cédric Karel J Van Goethem

State-of-the-art membranes for nanofiltration are thin film composite membranes, comprising of a thin top layer on top of a porous support. Many separation processes in organic chemistry involve extreme conditions, e.g. aggressive solvents, solvent-water m ...

Elsevier2023