Synthesis and Characterization of the Monolithic NiO-Al₂O₃Aerogels

Abstract

NiO-Al 2 O 3 aerogels without any visible cracks were prepared via a sol-gel method combined with the organic solvent sublimation drying (OSSD) technique. The high temperature thermal stability of the resulting NiO-Al 2 O 3 aerogel was improved. And it shows a well-developed mesoporous structure with uniform pore size distribution (∼6 nm) and a high specific surface area (∼318.69 m 2 /g). © The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. [DOI: 10.1149/2.0321602jss] All rights reserved.Manuscript submitted September 21, 2015; revised manuscript received November 9, 2015. Published December 12, 2015 Aerogels are highly porous solid materials derived from gels followed the substitution of liquid component with air from the pores of wet gels. [1][2][3][4][5] Due to their unique nanostructures, aerogels show low density, high porosity and high surface area and have been widely used in many fields, such as thermal insulation, catalysts, 6 catalyst carriers and sensors, 7 nuclear waste storage, and cosmic dust collectors. 8-13Alumina aerogel has received high attention because of its a number of unique properties, such as high strength, better thermal insulation (30 • C, 1 atm, thermal conductivity is 0.029 W/m · k), 14 and chemical durability at high temperatures. 12,15 By adding other materials to alumina aerogel could pertinently alter to increase its performance. For instance, we successfully prepared the attapulgite (ATP)/Al 2 O 3 aerogels and found that ATP improved the strength of alumina aerogels.16 Al 2 O 3 -SiO 2 aerogels show higher mechanical strength and heat insulation performance.17 Ceramic fiber/silica aerogels have stronger mechanical properties than single silica aerogels.18 Fe 2 O 3 -Al 2 O 3 aerogels can be applied for selective hydrogenation reaction of sulfur dioxide. 19NiO-Al 2 O 3 aerogels, as one of doped materials, also have many excellent properties and has been widely studied. As early as decades ago, there were scientists studying NiO-Al 2 O 3 aerogels. The reducibility of the NiO can be decreased when certain amount of Al 2 O 3 added.20,21 Mesoporous NiO-Al 2 O 3 catalysts have high oxidative activity and selectivity in partial oxidation of methane.22 Xu et al. 23 observed that ordered mesoporous NiO-Al 2 O 3 composite oxides presented both high catalytic activity and long stability for the carbon dioxide reforming of methane reaction. Although NiO-Al 2 O 3 composite aerogel could be prepared by related template method, some of these methods are difficult to carry out and some products do not possess good performance. And researchers pointed out that it was difficult to obtain composite aerogel material with more centered pore size distribution and high specific surface area. 24,25 Organic solvent sublimation drying (OSSD) technique...

Cerium-Based Bimetallic Oxides as Catalysts for the Methanation of CO2: Influence of the Preparation Method

“…Subsequently, 3.86 mL of PO was added to the solution and the mixture was stirred for 5 min. The gel obtained was sealed in the preparation vessel and aged in absolute ethanol for 48 h at 50 °C and then dried by the organic solvent sublimation drying method successively using replacement solutions of 50, 80, and 100% of acetonitrile/ethanol (v/v), each one over 24 h at the same temperature as that of the aging stage. − Finally, to obtain the bimetallic oxides, the aerogels were calcined at 500 °C under a heating rate of 1 °C/min for 2 h, the product ground, and the particle size reduced to 200 mesh (75 μm) and stored.…”