Neutron imaging from probing KOH distributions in porous carbon-based for direct air capture materials

The use of porous carbon materials for direct air capture (DAC) of CO2 is a rapidly growing field. Functionalisation with hydroxide allows for strong, chemisorption binding of CO2 allowing separation for dilute gas streams (e.g. air @ 440ppm CO2). We have developed inexpensive and facile potassium hydroxide impregnation methods into a range of porous carbon cloth materials. These have shown promising CO2 uptakes from air (0.2-0.6 mmol g-1) and strong robust to cycling, avoiding oxidative degradation common in amine-based systems. Understanding changes of impregnated KOH crystallite structure and distributions within the porous carbons plays a vital role in both optimising material synthesis and loading, as well as material performance over time and in response to external conditions (e.g. humidity). Having obtained initially promising neutron imaging results, we propose to investigate KOH distribution in a series of impregnated carbons (non-porous, medium porosity and high porosity) as a function of both humidity exposure and before/after material cycling.