Small-angle X-ray scattering experiments and computer simulations to characterise anisotropy of activated carbons prepared from wood

Abstract

Small-angle scattering was measured from activated carbon monoliths prepared from three different wood species (European beech, Pedunculate oak and Norwegian spruce). Substantial differences were found in the scattering images of axial and tangential slices, attributed to their characteristic phytogenic structures. The decrease in anisotropy in the nanostructured carbon matrix due to the activation process is also different among the three investigated types of wood. For quantitative characterization of the anisotropy and its decrease, the degree of alignment was calculated from the azimuthal scattering curves. A simple numeric model was constructed on the basis of direct information obtained by atomic force microscopy. Scattering patterns calculated from the model were compared with the experimental ones to explain the possible structural changes in the carbon skeleton.

Conformal Ultrathin Coating by scCO2-Mediated PMMA Deposition: A Facile Approach To Add Moisture Resistance to Lightweight Ordered Nanocellulose Aerogels

“…Small-angle X-ray scattering curves have been evaluated using a modified Guinier approach that considers the fibrillar structure of i -CNF and yields, hence, the cylinder radius of gyration R c of the cellulose nanorods as network building structures. In the low q regime the SAXS scattering curve follows a power law: I ( q ) ∼ A · q – n with A being a constant and n the slope of the curve in a double logarithmic plot, which is an indication for the fractal dimension of the network . A value of n = 1 would be indicative for a structure composed of loosely connected nanoscale rodlike building blocks while values of 2 and 3 would be caused by interlinked chains or clustered networks, respectively.…”

“…In the low q regime the SAXS scattering curve follows a power law: I(q) ∼ A•q −n with A being a constant and n the slope of the curve in a double logarithmic plot, which is an indication for the fractal dimension of the network. 45 A value of n = 1 would be indicative for a structure composed of loosely connected nanoscale rodlike building blocks while values of 2 and 3 would be caused by interlinked chains or clustered networks, respectively.…”

Pore Development during the Carbonization Process of Lignin Microparticles Investigated by Small Angle X-ray Scattering

“…The necessity of SAXS to access buried porosity was shown, e.g., with the characterization of disordered carbons [ 21 ]. With the possibility of pore characterization, the method also features as an easily applicable tool to follow pore development, e.g., changing materials anisotropy and changing structural features in activated carbons from wood [ 22 ], the development of porosity in deposited charcoal [ 23 ], the charcoal properties dependent on pyrolysis temperature [ 24 ] or the change of aggregates in carbon black pastes with aging [ 25 ].…”

Biomorphic Cellular Silicon Carbide Nanocrystal-Based Ceramics Derived from Wood for Use as Thermally Stable and Lightweight Structural Materials

“…Pyrolytic biocarbon templates (C B -templates) are shown in the schematic in Figure 1(a); rectangular specimens in both the radial (⊥) and axial (||) orientations with dimensions of 70 mm × 15 mm × 15 mm were cut from spruce wood which were fully naturally dried (from a furniture factory in the Nanming District, Guiyang, China). Subsequently, the rectangular specimens were dried at 110 °C for 24 h. 27 The dry processing is intended to remove the small amount of water inside the wood. The dried specimens were pyrolyzed at 1000 °C for 4 h under N 2 atmosphere with a low heating rate of 3 °C•min −1 , resulting in a porous biocarbon template (C B -template).…”