Post-combustion CO2 capture using mesoporous TiO2/graphene oxide nanocomposites

• TiO2/GO nanocomposites with different GO content prepared by colloidal blending.
• Synthesized nanocomposites systematically evaluated as adsorbent for CO2 capture.
• TiO2/GO have CO2 adsorption capacity of up to 1.88 mmol g−1 at 25 °C.
• TiO2/GO feature fast CO2 uptake kinetics and high CO2/N2 selectivity.
• The nanocomposite also exhibit low energy consumption for regeneration.

The development of robust adsorbents with high adsorption capacity and high selectivity to separate CO2 from flue gas streams, a major greenhouse gas contributing to global warming, is a topic of current global interest. In this study, a series of mesoporous titanium dioxide/graphene oxide (TiO2/GO) nanocomposites, with different GO to TiO2 mass ratios, were synthesized using a simple colloidal blending process and systematically investigated for the first time as potential CO2 adsorbent materials. The synthesized composites were characterized by diffraction, spectroscopy, and microscopy techniques. Pure component adsorption isotherms of CO2 were measured at 0, 25, and 50 °C and pressures up to 100 kPa. Analysis of adsorption results showed that the CO2 adsorption isotherms could be well fitted to the temperature dependent Toth model. The adsorption kinetic data were well-represented by the Avrami model. TiO2/GO exhibited a CO2 uptake capacity of 1.88 mmol g−1 at room temperature, which is much higher than many other commonly used adsorbents. Moreover, TiO2/GO also demonstrated a low heat of adsorption and remarkably high CO2/N2 selectivity and hence merits further consideration for capturing CO2 from dry flue gas.

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