Tailor-Made Core–Shell CaO/TiO₂–Al₂O₃ Architecture as a High-Capacity and Long-Life CO₂ Sorbent

Abstract

CaO-based sorbents are widely used for CO2 capture, steam methane reforming, and gasification enhancement, but the sorbents suffer from rapid deactivation during successive carbonation/calcination cycles. This research proposes a novel self-assembly template synthesis (SATS) method to prepare a hierarchical structure CaO-based sorbent, Ca-rich, Al2O3-supported, and TiO2-stabilized in a core-shell microarchitecture (CaO/TiO2-Al2O3). The cyclic CO2 capture performance of CaO/TiO2-Al2O3 is compared with those of pure CaO and CaO/Al2O3. CaO/TiO2-Al2O3 sorbent achieved superior and durable CO2 capture capacity of 0.52 g CO2/g sorbent after 20 cycles under the mild calcination condition and retained a high-capacity and long-life performance of 0.44 g CO2/g sorbent after 104 cycles under the severe calcination condition, much higher than those of CaO and CaO/Al2O3. The microstructure characterization of CaO/TiO2-Al2O3 confirmed that the core-shell structure of composite support effectively inhibited the reaction between active component (CaO particles) and main support (Al2O3 particles) by TiO2 addition, which contributed to its properties of high reactivity, thermal stability, mechanical strength, and resistance to agglomeration and sintering.

Screening of inert solid supports for CaO-based sorbents for high temperature CO2 capture

“…It can be seen from the carbonation rate curves that the peak values of carbonation rate at 15th cycle of Ca100 and Ca_L decrease compared with those at the 1st cycle, which is due to the sintering. However, almost all the synthetic sorbents exhibit increased peak values of carbonation rate after experiencing 15 carbonation/calcination cycles, well agreeing with the previous findings [50]. Except Y-, Mg-supported sorbents, the ranking of peak values of the last-cycle carbonation rate for the synthetic sorbents is similar to the trend of the performance decay as discussed above.…”

Natural Calcium‐Based Sorbents Doped with Sea Salt for Cyclic CO2 Capture

“…Qin et al and Luo et al produced pelleted sorbents through extruded mixtures of calcium precursor and cements, and found better CO 2 capture during long‐term cycles; Sun et al further proposed biomass‐based pore‐forming technology to improve the pore structure of the extruded pellets, and to enhance their CO 2 absorption. Some researchers incorporated inert materials, such as, MgO , Ca 12 Al 14 O 33 , TiO 2 , CaZrO 3 , La 2 O 3 , Nd 2 O 3 , Ca 2 MnO 4 , and so on , , to improve the long‐term stability of sorbents. Yang et al and Gupta et al prepared high‐surface‐area precipitated calcium carbonate by using a wet precipitation process.…”

Sr doping magnetic CaO parcel ferrite improving catalytic activity on the synthesis of biodiesel by transesterification

“…Then, an aqueous solution of NaOH (14.2 mmol) in deionized water (10 mL) was added dropwise into the mixture under a vigorous agitation at room temperature and then the resultant mixture was kept with stirring for 30 min. Sequentially, the system was aged at 65°C for 18 h. After filtered, the resulting precipitation was washed with saturated calcium hydroxide solution, and dried in a vacuum oven at 80°C for 12 h. The dried sample was then calcined at 700°C for 3 h at a heating rate of 2°C/min [27].…”