Scalable Synthesis of Amine-Grafted Ultrafine Layered Double Hydroxide Nanosheets with Improved Carbon Dioxide Capture Capacity from Air
Bingyao Ge, Chunping Chen, Zhuozhen Gan, Xuancan Zhu, Yihe Miao, Yaozu Wang, Tianshu Ge, Dermot O’Hare, R.Z. Wang
Abstract
The development of efficient adsorbents is one of the key technologies for direct air capture (DAC). Herein, a facile and scalable method to synthesize amine-functionalized layered double hydroxides (LDHs) as efficient DAC adsorbents is presented. Specifically, ultrafine and exfoliated Mg 2 Al–CO 3 LDH nanosheets were generated within 2 min via rapid nucleation and aging followed by organic solvent treatment, and they remained exfoliated on the powders after vacuum drying. The well-dispersed LDH nanosheets were grafted with a high density of monolayered aminosilane (5.51 mmol N g –1 ), leading to a good CO 2 adsorption capacity (0.68 mmol g –1 ) among amine-grafted adsorbents. Additionally, it exhibited good stability with no degradation over 200 adsorption–desorption cycles under ∼20% humid air at 25 °C.