Atomic resolution electron microscopy of nano-pores in 2D materials for blue energy.

The salinity gradients that occur where fresh water flows into salty ocean water represent a very large and almost completely untapped source of clean, so called blue energy, based on osmosis. One reason blue energy remains untapped is the inefficiency of current methods to harvest it, mostly due to the poor performance of the membrane processes being used. A promising potential solution to this problem is to use atomically thin 2D materials with nanopores in them as the membranes. Proof of principle experiments with nanopores in 2D materials have demonstrated osmotic power densities up to six orders of magnitude better than conventional membranes. Charge buildup around the nanopores creates a filter that allows salt ions with only one sign of charge to be driven by the chemical potential gradient from a salty reservoir through the pores and into a fresh water reservoir. Much like in a battery, the resulting segregated charge build up creates an electrical potential difference that can be used for electrical power. However, in order to enable maximum efficiency power generation from blue energy, a better understanding of the nanopores is needed. At present even basic knowledge such as their atomic structures remains lacking. In this project we will determine the atomic structure of nanopores which have been characterised for blue energy performance and develop methods of probing the charge density and electric fields at and around the nanopores with electron microscopy. In conjunction with first principles theory we will use the correlations between blue energy performance and the findings of the microscopy experiments to understand the physics of osmotic power production with nanopores in different 2D materials. We will thus uncover what makes the best nanopore based membranes, facilitating the engineering of nanopores with optimal blue energy performance.

Keywords:GRAPHENE, 2D MATERIALS, NANOFLUIDICS, ELECTRON MICROSCOPY (TRANSMISSION)

Disciplines:Nanophysics and nanosystems, Structural and mechanical properties, Surfaces, interfaces, 2D materials