07/10/2023
Publication Alert in JACS Au
Title: Selective Photonic Gasification of Strained Oxygen Clusters on Graphene for Tuning Pore Size in the Å Regime
Amidst the pressing concerns of global warming, there's an emergent demand for energy-efficient gas separation techniques. Membranes, with their inherent energy efficiency and simplicity, stand out as promising solutions. In this regard, single-layer graphene, owing to its atomic thickness, holds the potential for unparalleled gas permeance and selectivity. However, achieving a precise and consistent pore size distribution remains a significant challenge.
In a pioneering study, researchers from EPFL, Switzerland, and the Department of Chemical Engineering, IISc, Bangalore, have unveiled a groundbreaking method for photonic gasification of oxygen clusters on single-layer graphene. This allows for an unprecedented capability to independently tailor pore size and density. Initial steps involved the growth of oxygen clusters (acting as pore precursors) on the graphene using ozone. The inherent strain within these clusters forms an ether core, which when exposed to brief light exposure, undergoes gasification, resulting in highly precise control over pore size.
By modulating the temperature during ozone functionalization, the team was able to influence the cluster formation kinetics. Notably, this allowed a decoupling between pore density and size— traditionally viewed as a trade-off in the field. The implications are immense: achieving this balance led to superior H2 permeance while retaining optimal H2/N2 and CH4/N2 selectivity. Additionally, dedicated molecular dynamics simulations were performed to analyze the atomistic details of the gas permeation and selectivity.
This rapid and precise method, termed photonic gasification, heralds a significant advancement in the scalable applications of nanoporous graphene membranes.
Credits:
Guidance & Supervision:
Kumar Varoon Agrawal (EPFL),
Ganapathy Ayappa (Department of Chemical Engineering, IISc, Bangalore),
Oleg Yazyev (EPFL)
Lab Experiments & AC-HRTEM Imaging: Luc Bondaz
MD Simulations: Anshaj Ronghe and Luc Bondaz
DFT Computations: Kristians Cernevics and Anshaj Ronghe
XPS Study: Shaoxian Li
Ozone Gasification Insights: Jian Hao
Controlling the size of single-digit pores, such as those in graphene, with an Å resolution has been challenging due to the limited understanding of pore evolution at the atomic scale. The controlled oxidation of graphene has led to Å-scale pores; however, obtaining a fine control over pore evolut...