Structure and Physical Properties of Tailor-Made Ce,Zr-Doped Carbon Aerogels

Abstract

Carbon aerogels with controlled porosity can be obtained by doping the resorcinol–formaldehyde reaction mixture with Ce and/or Zr. As highlighted here, the concentration of metal dopant and the pH of the initial reaction mixture can have a profound effect on the structure, porosity, and physical properties of the resulting aerogel. The Figure shows the morphology of a Ce,Zr‐doped carbon aerogel synthesized at pH 7.

Hierarchically Nanoporous Zeolites and Their Heterogeneous Catalysis: Current Status and Future Perspectives

“…The multi-walled carbon nanotubes [37,38], carbon nanofibers [39] and carbonized sucrose [40,41] were also used as the successful hard-templates. Tao et al synthesized an MFI zeolite monolith containing regular arrangement of uniform-sized mesopores using carbon aerogel monolith as a template [42] that was prepared through pyrolysis of resorcinol-formaldehyde resin [43][44][45][46][47]57]. Textural properties of mesopores in the resultant hierarchical zeolites were tunable by the particle size constituting the carbon aerogel.…”

Designing Nanostructured Carbon Xerogels

“…However, it is not the only one that determines the performance as the surface chemistry is also a key factor. Thus, several studies focus on the incorporation of oxygen functional groups by means of different oxidation processes (Mahata et al, 2008;Silva et al, 2009), the incorporation of nitrogen groups by using nitrogen-containing monomers or post-synthesis treatments (Gorgulho et al, 2009;Kang et al, 2009;Long et al, 2008b;Pérez-Cadenas, 2009) and the modification of carbon gels with the incorporation of metal species into the carbon framework (Bekyarova & Kaneko, 2000;Chandra et al, 2011;Cotet et al, 2006;Job et al, 2007b;Tian et al, 2010). In the synthesis process of carbon gels based on sol-gel methodology, these above-mentioned treatments can be performed using different reagents and conditions, making it necessary to optimize the operating conditions to meet the requirements of each individual case.…”

“…Moreover, the temperature determined the type of tungsten particles inside the carbon structure, since carbonization at 500 °C produced materials composed of needle-like WO 3 particles with a radius of few nanometres, while when the temperature was set at 1000 °C, as well as the same type of particles, a denser species with a certain dendritic character were obtained. The surface chemistry of metal-doped carbon gels are also conditioned by the pH of the precursor solution (Bekyarova et al, 2000) like the textural properties. Bekyarova and Kaneko (Bekyarova et al, 2000) prepared Ce,Zr-doped carbon aerogels by adding metal salts to the resorcinol-formaldehyde solutions.…”

Template-based syntheses for shape controlled nanostructures

“…Carbon aerogels (CAs) [63,[70][71][72][73][74] are obtained in monolithic form and their structures and properties depend on the agglomerate structures of uniform spherical carbon particles [63,73,75]. CAs show an adsorption isotherm type IV, which is typical from mesoporous materials [63,76].…”