(3ic) Engineering Nanopore in the Two-Dimensional Film for High-Performance Separation

Attributing to their atomic thicknesses and unique physical/chemical properties, two-dimensional (2D) materials show great potential to realize the ultimate separation performance. However, the density-gap of most of the 2D lattice prevents even the smallest gas molecule He permeates, such as graphene, hexagonal boron nitride (h-BN), Molybdenum disulfide (MoS₂). Perforation of the impermeable lattice with high-density nanopores with narrow distribution would be the essential step to create the channel for molecules transport. We have demonstrated a series of works about nanopore engineering in single-layer graphene for gas separation by uniform chemical etching. The resulting film hosted 1% gas-sieving nanopores and realized excellent gas separation performance, targeting to the efficient carbon capture.

These advances paved the way for us to experimentally realize the state-of-the-art and the theoretically predicted 2D membrane performance, although there is still a big gap between them. In addition, this finding provides a new opportunity to understand the unique physical/chemical properties of the nanoporous 2D materials. I am interested in exploring to following related fields, 1) understand the mechanism of the nanopore formation in 2D film, and develop an engineering tool to precise control pore size and pore-size distribution; 2) probe the physical property of the nanoporous 2D film, such as adsorption and transport barrier; 3) integrate the catalytic reaction and membrane separation based on the nanoporous 2D film.

Research experience

My research experience is related to the nanoporous membranes for gas separation (during Ph.D.) as well as the membrane reactor (during Master). My Ph.D. work focused on realizing high-performance gas-sieving single-layer graphene membrane with sub-angstrom resolution. For the first time, I have demonstrated a millimeter-scale crack-free single-layer graphene membrane for gas separation. Followed by this, a novel millisecond gasification reactor was developed to incorporate high-density gas-sieving nanopores in a single-layer graphene membrane, realizing the high-performance CO₂/N₂ separation. By revealing the ozone-etching mechanism, I have built a mathematical model to predict the pore-size distribution and guide the etching experiment. Apart from this, I was involved in several projects related to the development of high-performance thin membranes, such as ultra-thin carbon molecular sieve membrane, hybrid graphene membrane, and scale-up membrane process. During my Master's, I designed a new configuration to integrate multiple reactions into one electrochemical hydrogen pump (EHP) reactor by making use of the unique membrane barrier. This also provides a platform for coupling gas separation with reaction, exhibiting better yield and stability.

Selected publication

1. Huang, L. F. Villalobos, D. J. Babu, S. Li, M. T. Vahdat, E. Oveisi, K. V. Agrawal*, "High-permeance singlelayer graphene membrane with a molecular sieving resolution of 0.2 Å", Submitted
2. Huang, M. Dakhchoune, W. Luo, E. Oveisi, G. He, M. Rezaei, J. Zhao, A. Züttel, M. S. Strano, K. V. Agrawal*, "Single-layer graphene membranes by crack-free transfer for gas mixture separation", Nature Communications, 2018, 9, 2632.
3. Huang, L. F. Villalobos, D. J. Babu, G. He, M. Li, A. Züttel, K. V. Agrawal*, "Ultrathin carbon molecular sieve films and room-temperature oxygen functionalization for gas-sieving", ACS Applied Materials & Interfaces, 2019,11, 16729-16736
4. He, S. Huang, L. F. Villalobos, J. Zhao, M. Mensi, E. Oveisi, M. Rezaei, K. V. Agrawal*, "High-permeance polymer-functionalized single-layer graphene membranes that surpass the postcombustion carbon capture target", Energy & Environmental Science, 2019, 12, 3305.
5. He, S. Huang, L. F. Villalobos, M. T. Vahdat, M. D. Guiver, J. Zhao, W.-C. Lee, M. Mensi, K. V. Agrawal, "Synergistic CO2-sieving from polymer with intrinsic microporosity masking nanoporous single-layer graphene", Advanced Functional Materials, 2020, Just Accepted
6. Zhao, G. He, S. Huang, L. F. Villalobos, M. Dakhchoune, H. Bassas, K. V. Agrawal*, "Etching nanopores in single-layer graphene with an angstrom precision for high-performance gas separation", Science Advances, 2019, 5, eaav1851.
7. Huang, X. Wu,* W. Chen, T. Wang, Y. Wu, G. He*, "Bilateral electrochemical hydrogen pump reactor for 2-propanol dehydrogenation and phenol hydrogenation", Green Chemistry, 2016, 18, 2353-2362
8. Huang†, T. Wang†, X. Wu, W. Xiao, M. Yu, W. Chen, F. Zhang, G. He*, "Coupling hydrogen separation with butanone hydrogenation in an electrochemical hydrogen pump with sulfonated poly (phthalazinone ether sulfone ketone) membrane", Journal of Power Sources, 2016, 327, 178-186.

Teaching interest

My teaching experience is mainly related to the Chemical Engineering curriculum. I started my TA of fluid dynamics and involved in exercise lectures since my Master's. During my Ph. D. at EPFL, I have been as the TAs of the "Advance diffusion separation process," "Process development," and "Chemical engineering lab project." These experiences have further improved my teaching skills and prepared me to communicate effectively with the students.