In this study we report on mechanical properties of molded, single component Al 2 O 3 , Ga 2 O 3 , Fe 2 O 3 , and ZrO 2 as well as mixed aerogels, made from yttrium stabilized zirconia, yttrium aluminum garnet, and zinc aluminum spinel. Initially all aerogels were produced equally in molded bodies by a facile epoxy method and were annealed afterward at 300 °C. Then we performed uniaxial pressure tests on cylindrical aerogel monoliths to gain Young's modulus which depends on composition, density, and posttreatment. Already pure aerogels like ZrO 2 show wellpromising Young's modulus of 10.7 MPa, whereas most popular SiO 2 materials display a modulus between 2 and 3 MPa at comparable densities. Moreover we focused on Al 2 O 3 aerogels which exhibit high stability and interesting densification behavior depending on the annealing temperature. On the basis of this observation, we combined the toughness of the Al 2 O 3 scaffold with the extraordinary hardness of ZrO 2 , by adding up to 20 atom % Zr, to increase the specific Young's modulus. For the mixed material with a Zr content of 20 atom %, we reach a record value for compressible aerogels of 125 MPa mL g −1 .
Methanol steam reforming provides clean hydrogen by onboard production, which can directly be used for fuel cell applications−while using appropriate catalysts. In x Pd y /In 2 O 3 aerogels exhibit excellent CO 2 selectivities of 99%. This is caused by the active participation of chemically bound oxygen from the material as proven by isotope-labeling experiments. In addition, the dynamic, temperature-dependent equilibrium between intermetallic and oxidic species has a strong impact on the catalytic properties of the material. Thus, the intermetallic compounds in close proximity to a supporting reducible oxide act as selectivity-decisive redox centers, enabling a Mars-van Krevelen mechanism, which is responsible for the excellent selectivity toward CO 2 .
Solar radiation is a versatile source of energy, convertible to different forms of power. A direct path to exploit it is the generation of heat, for applications including passive building heating, but it can also drive secondary energy‐conversion steps. We present a novel concept for a hybrid material which is both strongly photo‐absorbing and with superior characteristics for the insulation of heat. The combination of that two properties is rather unique, and make this material an optical superheater. To realize such a material, we are combining plasmonic nanoheaters with alumina aerogel. The aerogel has the double function of providing structural support for plasmonic nanocrystals, which serve as nanoheaters, and reducing the diffusion rate of the heat generated by them, resulting in large local temperature increases under a relatively low radiation intensity. This work includes theoretical discussion on the physical mechanisms impacting the system's balanced thermal equilibrium.
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