ABSTRACT
In order to enable future use of aerogels in heterogeneous solid or fluidized bed catalysis a method of production of millimeter sized monolithic Au/Al2O3 aerogel spheres by a continuous flow reactor is developed. Flow velocities and synthesis parameters are optimized to produce aerogel spheres in three different sizes. The resulting aerogel spheres exhibit a porous aluminium oxide aerogel matrix with a large specific surface area of 400 m2 g-1 on which gold nanoparticles are evenly distributed. The aerogel spheres are compared to xerogels of the same material in contrast to their surface area, pore size distribution, morphology, crystal structure and thermal properties. The presented method allows a broad access to various mixed aerogel systems of oxidic carrier material and noble metal nanoparticles and is therefore relevant for the shaping of different aerogel catalyst systems.
ABSTRACT
A novel synthesis method for ordered mesoporous carbons is presented. The inverse replication of a silica template was achieved using the carbonization of sucrose within mesoporous KIT-6. Instead of liquid acid etching, as in classical nanocasting, a novel dry chlorine etching procedure for template removal is presented for the first time. The resultant ordered mesostructured carbon material outperforms carbons obtained by conventional hard templating with respect to high specific micro- and mesopore volumes (0.6 and 1.6 cm(3) g(-1) , respectively), due to the presence of a hierarchical pore system. A high specific surface area of 1671 m(2) g(-1) was achieved, rendering this synthesis route a highly convenient method to produce ordered mesoporous carbons.
ABSTRACT
There is significant interest in high-performance materials that can directly and efficiently capture water vapor, particularly from air. Herein, we report a class of novel porous carbon cuboids with unusual ultra-hydrophilic properties, over which the synergistic effects between surface heterogeneity and micropore architecture is maximized, leading to the best atmospheric water-capture performance among porous carbons to date, with a water capacity of up to 9.82â mmol g(-1) at P/P0 =0.2 and 25 °C (20% relative humidity or 6000â ppm). Benefiting from properties, such as defined morphology, narrow pore size distribution, and high heterogeneity, this series of functional carbons may serve as model materials for fundamental research on carbon chemistry and the advance of new types of materials for water-vapor capture as well as other applications requiring combined highly hydrophilic surface chemistry, developed hierarchical porosity, and excellent stability.