Water-Dispersible Nanocatalysts with Engineered Structures: The New Generation of Nanomaterials for Energy-Efficient CO2 Capture.

The high energy demand of CO2 absorption-desorption technologies has significantly inhibited their industrial utilization and implementation of the Paris Climate Accord. Catalytic solvent regeneration is of considerable interest due to its low operating temperature and high energy efficiency. Of the catalysts available, heterogeneous catalysts have exhibited relatively poor performances and are hindered by other challenges, which have slowed their large-scale deployment. Herein, we report a facile and eco-friendly approach for synthesizing water-dispersible Fe3O4 nanocatalysts coated with a wide range of amino acids (12 representative molecules) in aqueous media. The acidic properties of water-dispersible nanocatalysts can be easily tuned by introducing different functional groups during the hydrothermal synthesis procedure. We demonstrate that the prepared nanocatalysts can be used in energy-efficient CO2 capture plants with ease-of-use, at very low concentrations (0.1 wt %) and with extra-high efficiencies (up to ∼75% energy reductions). They can be applied in a range of solutions, including amino acids (i.e., short-chain, long-chain, and cyclic) and amines (i.e., primary, tertiary, and primary-tertiary mixture). Considering the superiority of the presented water-dispersible nanocatalysts, this technology is expected to provide a new pathway for the development of energy-efficient CO2 capture technologies.