Abstract
CO2 capture remains crucial for reducing emissions from hard-to-decarbonize industries such as cement and steel from where flue gases are typically released at elevated temperatures. This necessitates development of thermally stable sorbents that can rapidly and selectively capture CO2. In this study, we report a mesoporous rGO@K20-MgO composite, synthesized by incorporating potassium (K)-doped MgO nanoparticles into a reduced graphene oxide (rGO) framework. Structural and textural analyses confirmed that K doping introduced abundant surface basic sites and rGO preserved mesoporosity (2–21 nm) and suppressed particle agglomeration. The optimized composition achieved a CO2 uptake of 5.16 mmol/g at 150 °C. This represented a 58% improvement, over pristine MgO, and nearly double the adsorption rate and decent cyclic stability. Breakthrough experiments demonstrated that increasing the total pressure to 5–10 bar partially recovered the dynamic CO2 capacity under multicomponent CO2/N2/NO/SO2 mixtures. These results demonstrate that the composite maintains appreciable CO2 uptake at high temperature and pressure and in the presence of impurity thus highlighting its potential for practical post-combustion capture.
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•Thermally robust mesoporous rGO@K-MgO composite developed for high-temperature post-combustion CO2 capture from cement/steel flue streams.•K-doping enriched surface basicity, while rGO preserved 2-21 nm mesoporosity and mitigated MgO nanoparticle agglomeration, enhancing diffusion efficiency.•High CO2 uptake of 5.16 mmol g-1 at 150 °C, marking a 58% increase over pristine MgO with ~2× faster adsorption kinetics.•Demonstrates good cyclic stability under repeated adsorption-desorption operation.