Biotemplated Lightweight γ-Alumina Aerogels

Abstract

We present the biotemplating of γ-Al 2 O 3 aerogels with chitosan nanofibrils. Aluminum−chitosan interactions cause the swelling of iridescent chitosan structures into helicoidal hydrogels and the subsequent aqueous dissolution of swollen fibrils to form Al− chitosan solutions. Viscous aqueous solutions of Al 3+ −chitosan hybrid nanofibers were freeze-dried to give lightweight cotton-like aerogels. Homogeneous incorporation of Al 3+ ions into chitosan yields water-soluble nanofibrils that can serve as polymeric templates to support Al 3+ ions in the aerogel composites. We investigated thermal removal of chitosan in the composites to obtain lightweight γ-Al 2 O 3 nanocrystal aerogels that retain the weblike fiber networks of the chitosan template. These biotemplated alumina aerogel materials are promising candidates for catalyst supports and thermal insulation.

Konjac glucomannan-templated synthesis of three-dimensional NiO nanostructures assembled from porous NiO nanoplates for gas sensors

“…The meso-and macroscale pores may be formed by the agglomeration of NiO nanoparticles 34 and assembly of the nanoplates. 8 The novel porous NiO nanostructures usually give rise to the unique gas sensing properties originating from the defective sites on their surface. The gas sensing behavior of the as fabricated mesoporous NiO nanoplates was tested with H 2 S, NH 3 , CO and H 2 gases.…”

“…Song et al 7 reported the successful fabrication of mesoporous TiO 2 with high exposure of the (001) faces using a cellulose nanocrystal template. Nguyen et al 8 successfully converted hierarchical chitosan nanobril templates into lightweight g-Al 2 O 3 aerogels.…”

Fabrication and application of macroscopic nanowire aerogels

“…In addition to the emulsion template method, a bio-template method has been developed by MacLachlan's group for the fabrication of light-weight alumina nanofiber aerogels. 65 In this method, the biomaterial chitosan nanofibrils as templates were mixed with Al 3+ aqueous solution to produce Alchitosan hydrogels that can be converted to an aerogel by freeze-drying. Thermal decomposition of the composite aero-gels yielded Al 2 O 3 aerogels that possessed similar structural organization as that of the chitosan nanofibril aerogels.…”

TỔNG HỢP TẤM NANO Fe2O3 SỬ DỤNG GLUCOMANNAN LÀM CHẤT ĐỊNH HƯỚNG CẤU TRÚC

“…Việc sử dụng polymer tự nhiên làm chất định hướng cấu trúc để tổng hợp các vật liệu nhẹ và có độ xốp cao rất được quan tâm vì loại polymer này thân thiện với môi trường, phong phú, có cấu trúc độc đáo và chi phí điều chế thấp [6]. Các polymer sinh học như peptide [7], dextran [8], xyloglucan [6], cellulose [9], chitin [10] và chitosan [11]…”