Aerogel‐like ceramic foams with super‐high porosity and nanoscale cell wall from sol nanoparticles stabilized foams

Abstract

Ultralight ceramic foam materials with high porosity play an important role in increasingly hi‐tech areas due to the combinative merit of ceramic material and highly porous structure. So far, it remains challenging to fabricate alumina ceramic foams with extremely high porosity and high specific surface area that are comparable to aerogel materials by employing a low cost, eco‐friendly and convenient approach. For the first time, we propose the preparation of aerogel‐like ceramic foams with nanoscale cell wall and unprecedentedly high porosity using boehmite sol as both ceramic source and bubble interface stabilizer, based on sol nanoparticles stabilized foams using sodium lauryl sulfate (SDS) as modifier. The obtained ultra‐stable sol foams allow for the achievement of bulk foams with ultrathin cell wall with thickness in the range of 30‐90 nm, super‐high porosity up to 99%, and large specific surface area of 280 m2/g, which is attributed to the well‐organized assembly of nanoparticles at the liquid/air interfaces. This novel foam material demonstrates excellent adsorption ability for polar volatile organic gases (VOCs) due to its extremely high porosity and large specific surface area.

Hierarchical porous ceramics with multiple open pores from boehmite gel emulsions

“…Other than commonly chosen microscale raw particles, nanoparticles would make for the improvement of porosity and specific surface area meanwhile lowering the sintering temperature 16 . Therefore, nanoscale boehmite particles were selected with their morphology displayed in Figure 1A.…”

“…There is an urgent need to develop a new approach to improve its forming process. As to particle‐stabilized foams method, gelation is proved to be a promising way fabricating porous green body with relatively high strength, and the production period could be greatly shortened, facilitating mass production of ceramic foams with high porosity and specific surface area 16‐18 . Thus, combining emulsification with gelation has been employed in this research to accelerate the curing green body with certain strength as well as open channels.…”

Ceramic foams with highly open channel structure from direct foaming method in combination with hollow spheres as pore-former

“…As illustrated in Fig. 1, the foams are subjected to solidi cation with the assistance of agar molecules in the case of ZrO 2 based foams [11] , and rapid gelation of boehmite nanoparticles was triggered by decreasing pH in the case of Al 2 O 3 based foams [12] . Therefore, the dried foams exhibit favorable strength, that keep the whole porous green body holding together and be free of breaking.…”

Hierarchical porous ceramics with multiple open pores from boehmite gel emulsions

“…Other than commonly chosen micro-scale raw particles, nanoparticles would make for the improvement of porosity and specific surface area meanwhile lowering the sintering temperature [17] . Boehmite nanoparticles were selected in this research with their morphology present in Fig.…”