Exfoliated Ni-Al LDH 2D nanosheets for intermediate temperature CO2 capture

Abstract

CO₂ capture is projected as one of the pragmatic approaches to deal with the global warming phenomenon. Adsorption-based CO₂ capture is considered an economically attractive option to reduce CO₂ emission. The success of the adsorption-based capture primarily relies on adsorbents and thus a variety of adsorbents have been investigated in the literature. We here report a high surface area (210.2 m²/g) exfoliated Ni-Al LDH nanoplatelet as a promising candidate for CO₂ capture at an intermediate temperature of 200 °C applicable to integrated gasification combined cycle (IGCC) and sorption enhanced water gas shift (SEWGS) reactions. The materials were well characterized by PXRD, TGA, FTIR, TEM, ICP-OES, and N₂ adsorption surface area, and pore size distribution techniques. A unique nanoflower morphology comprising of exfoliated LDH platelets of ca. 5 layer thickness was obtained. The CO₂ capture capacity (0.66 mmol/g) of the exfoliated Ni-Al LDH nanoplatelet is comparable to that of the widely reported Mg-Al LDH-derived mixed oxides and MgO-based adsorbents. Provided that Ni-Al and other transition metal LDH materials are known to exhibit superior catalytic properties for CO₂ methanation, this work could pave the way for development of dual-functional materials for CO₂ capture and conversion.

Keywords: CO(2) capture; Exfoliation; Nanosheets; Ni-Al LDH.