One-step and sustainable preparations of inert additive-doped CaO-based CO2 adsorbents by hydrogenation reduction of CaCO3

The development of inert additive-doped CaO-based CO2 adsorbents is a promising method to obtain efficient CO2 adsorbents, while multiple programs are frequently involved, the organic solvent is often used, and CO2 is sometimes released in the process of preparation. In this study, we first report that inert additive-doped CaO-based adsorbents can be synthesized in one pot by the mechanochemical hydrogenation reduction of CaCO3 producing methane and avoiding CO2 emission. The prepared CaO@C and CaO@MgO@C composites are highperformance CO2 adsorbents with high CO2 adsorption capacity and superior cycling stability. The results show that the CO2 capture capacities of the CaO@C and CaO@MgO@C composites are 19.14 and 14.53 wt% higher than that of the BM-CaO (37.07 wt%), respectively, at 650. C carbonation for 2 h. Notably, the activity losses of the CaO@C and CaO@MgO@C composites after 30 cycles are about 47.93 and 29.33%, which are much lower than that of the BM-CaO (60.39%). The performance of the CaO@C and CaO@MgO@C adsorbents is comparable to that of adsorbents synthesized by the conventional methods, but this work provides novel, simple, solutionfree, and sustainable strategies to synthesize effective CaO-based CO2 adsorbents in one pot.

Automated summary

The study shows that inert additive-doped CaO-based CO2 adsorbents can be synthesized in one pot by the mechanochemical method, producing methane instead of CO2 emission. The prepared CaO@C and CaO@MgO@C composites exhibit high CO2 adsorption capacity and superior cycling stability, with much lower activity losses after 30 cycles compared to conventional adsorbents. This work provides a novel, simple, solution-free, and sustainable strategy for synthesizing effective CaO-based CO2 adsorbents.