Synthesis of highly effective stabilized CaO sorbents via a sacrificial N-doped carbon nanosheet template

Abstract

Highly macroporous MgO-stabilized CaO nanosheets with rapid reaction rates, high capacity, and good stability for high-temperature CO2 capture.

Porous MgO-stabilized CaO-based powders/pellets via a citric acid-based carbon template for thermochemical energy storage in concentrated solar power plants

“…Interestingly, the phase of MgO was not detected by XRD. Thus, we speculated that MgO may be present as an amorphous phase and similar results were also observed by our previous study [39].…”

Mechanistic Understanding of CaO‐Based Sorbents for High‐Temperature CO2 Capture: Advanced Characterization and Prospects

“…Inert metal oxide stabilizers such as MgO do not form mixed phases with CaO and do not form carbonates at typical CaL conditions (i. e., T >600 °C) [54,63,76] . However, a similar tendency for agglomeration of the stabilizer phases as observed in reactive stabilizers (e. g., Al 2 O 3 or ZrO 2 ), is observed for inert stabilizers [12,23,76] .…”

“…[9,12,55] It is believed that stabilizers act as physical barriers between otherwise adjacent CaO grains, hence reducing the rate of sintering and stabilizing the pore network and surface area of the sorbent. [23,56,57] Various metal oxides have been explored as stabilizers including Al 2 O 3 [20,23,26,[58][59][60] (and the respective mixed calcium aluminates Ca x Al y O z that form during calcination [23,25,61] ), MgO, [17,18,24,54,62,63] SiO 2 , [64][65][66][67] TiO 2 [68] or ZrO 2 . [57,[69][70][71][72] Stabilizers are commonly added in quantities ranging between 5-20 wt %, with the optimal quantity being a trade-off between the degree of morphological stabilization and the quantity of CO 2 captureinert material added.…”

CO2 capture using solid sorbents: Fundamental aspects, mechanistic insights and recent advances

“…Sacrificial templates have been used to synthesize nanostructured sorbents with homogenously distributed stabilizers [119], [120], [378], [386]- [388], [390]- [396]. The resulting morphologies have been characterized as microspheres [119], [391], [394], [396], [397], [404], microtubes [393], cage-like structures [392], [405], and nanosheets [387]. The structures are principally a product of the shape of the templates such as carbonaceous spheres [286], [388] or hard templates of biomass including cotton [393], willow, straw and wheat [395], but there have also been examples where hollow structures were obtained without using carbonaceous templates by exploiting the Kirkendall effect [406], [407].…”