Reduced graphene oxide -MnO2 nanocomposite for CO2 capture from flue gases at elevated temperatures

The newly prepared reduced graphene oxide-MnO2 (rGO-MnO2) nanocomposite has exhibited highly selective CO2 adsorption from gaseous mixtures at elevated temperatures. The Mn2+ basic sites are scattered over the rGO-MnO2 nanocomposite which produce an effective BET surface area of 710 m(2) g(-1) for selective CO2 capture. The selective adsorption of CO2 (5.87 mmol g(-1)) over N-2 (0.36 mmol g(-1)) and CH4 (0.41 mmol g(-1)) at 298 K/1 bar was achieved by the nanocomposite. The heat of adsorption followed a unique correlation with the quantity of CO2 adsorbed and fits well to the Fowler-Guggenheim equation. The mechanism of CO2 adsorption on the nanocomposite was complemented with molecular modelling and simulations. The rGOMnO(2) have shown better CO2 adsorption capacity of 28.5 mmol g(-1) at 323 K/20 bar as compared to zeolite derivatives, MOFs, and carbons as reported in the literature. The formation of inert frameworks with 3-6 nm porous structure in the nanocomposite thermally stabilizes to capture CO2 repeatedly. The nanocomposite with adsorption capacity of 3.69 mmol g(-1) at 373 K/1 bar is quite close to real-life conditions for flue gas treatment. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The newly prepared reduced graphene oxide-MnO2 nanocomposite exhibits highly selective CO2 adsorption from gaseous mixtures at elevated temperatures, with a high adsorption capacity. This nanocomposite shows excellent CO2 adsorption performance under various conditions.