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

Abstract

• ▶ CaO-based adsorbent is sustainably synthesized by hydrogenation reduction of CaCO 3 . • ▶ The prepared CaO@C and CaO@MgO@C composites are high performance CO 2 adsorbent. • ▶ They exhibit higher CO 2 uptake capacity than that of the ball-milled CaO at 650 °C. • ▶ They also show faster adsorption rate and better cycling stability. • ▶ The work provides a novel and sustainable method to prepare CaO-based CO 2 adsorbent. The development of inert additive-doped CaO-based CO 2 adsorbents is a promising method to obtain efficient CO 2 adsorbents, while multiple programs are frequently involved, the organic solvent is often used, and CO 2 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 CaCO 3 producing methane and avoiding CO 2 emission. The prepared CaO@C and CaO@MgO@C composites are high-performance CO 2 adsorbents with high CO 2 adsorption capacity and superior cycling stability. The results show that the CO 2 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, solution-free, and sustainable strategies to synthesize effective CaO-based CO 2 adsorbents in one pot.