Stabilization of Layered Double Oxide in Hybrid Matrix of Graphene and Layered Metal Oxide Nanosheets: An Effective Way To Explore Efficient CO₂ Adsorbent

A novel methodology to explore efficient CO 2 adsorbent is developed by the stabilization of layered double oxide (LDO) in the hybrid matrix of reduced graphene oxide (rG-O) and layered titanate nanosheets. The electrostatically derived self-assembly between cationic Mg–Al–layered double hydroxide (LDH) nanosheet and anionic graphene oxide (G-O)/layered titanate nanosheets followed by heat treatment at high temperature leads to the cohybridization of LDO (MgO/MgAl 2 O 4 ) nanocrystals with exfoliated rG-O and layered titanate nanosheets. The incorporation of LDO into the hybrid matrix of rG-O and layered titanate nanosheets is highly effective in increasing its surface area through the formation of mesoporous stacking structure. Of prime importance is that even at very low concentration of titanate (0.3 wt %), an addition of layered titanate nanosheet induces a remarkable surface area expansion of LDO–rG-O nanocomposite from 178 to 330 m 2 g –1 . This result is attributable to the depression of the self-aggregation of rG-O nanosheets due to the incorporation of layered titanate nanosheet. The resulting LDO–rG-O–layered titanate nanocomposite shows promising CO 2 adsorption capability of 1.71 mmol g –1 at 273 K, which is much greater than those of LDO (0.79 mmol g –1 ) and LDO–rG-O nanocomposites (1.19 mmol g –1 ), highlighting the remarkable advantage of titanate addition to improve the CO 2 adsorptivity of LDO. The present study clearly proves that the restacked assembly of rG-O nanosheet and layered metal oxide one has potential applications as an efficient hybrid matrix for exploring high performance gas adsorbent.