posted on 2024-01-18, 17:33authored byNiketa A. K, Shishir Kumar
Nanoporous graphene is an ideal candidate
for molecular filtration
as it can potentially combine high permeability with high selectivity
at molecular levels. To make use of graphene in filtration setups,
the defects formed during its growth and during the transfer of graphene
to the carrier support pose a challenge. These uncontrolled pores
can be avoided by stacking graphene layers, and then, controlled pores
can be initiated with oxygen plasma. Here, we show that two-layer
stacks provide the best balance of defect coverage and high selectivity
compared with other stacks. Using the electrical characterization
of ionic solutions in the standard diffusion cell, we compare the
ionic transport and ionic selectivity of up to three-layered stacks
of graphene that have been plasma-treated. We find that there is a
decrease in the ionic selectivity of a two-layered stack as one more
layer of graphene is added. We provide a model for this occurrence.
Our results will be helpful for making practical and high-performance
filtration systems from two-dimensional materials.