A comparative review of performance of nanomaterials for Direct Air Capture

The rapid rise in atmospheric CO₂ levels necessitates the removal of greenhouse gases. Direct Air Capture (DAC), as a representative negative emission technology, is a method to capture CO₂ directly from the atmosphere and reduce global CO₂ concentrations. Nanomaterials, categorized as nano objects and nanostructured materials, will play an essential role in enhancing DAC efficiency and performance through the development of advanced adsorption materials. The high reaction surface areas and porosity of nanomaterials are the foundational variables contributing to high rates of CO₂ capture. Given that, this review aims to provide a comprehensive investigation of the novel nanomaterials in DAC, particularly with respect to parameters including material capture capacity, stability, effect of humidity, and cost. This review found that while nanofibers offer effective CO₂ uptake under low pressure, they offer poor structural stability – a shortcoming overcome by the diverse structural flexibility found in nanocomposite materials and their comparatively affordable fabrication costs. However, further research and commercial development are needed for these materials to increase the adsorption capacity and stability, as well as, importantly, reducing cost and energy consumption.