6Porous graphitic carbons were successfully obtained from wood precursors through 7 pyrolysis using a transition metal as catalyst. Once the catalyst is removed, the resulting 8 material mimics the microstructure of the wood and presents high surface area, open and 9 interconnected porosity and large pore volume, high crystallinity and good electrical 10 conductivity, making these carbons interesting for electrochemical devices. Carbons 11 obtained were studied as electrodes for supercapacitors in half cell experiments, obtaining 12high capacitance values in a basic media (up to 133 F·g -1 at current densities of 20 mA·g -1 13 and 35 F·g -1 at current densities of 1 A·g -1 ). Long-cycling experiments showed excellent 14 stability of the electrodes with no reduction of the initial capacitance values after 1000 15 cycles in voltammetry. 16

Graphitic porous carbon materials from pyrolysis of wood precursors were obtained by means of a nanosized Fe catalyst, and their microstructure and electrical and thermal transport properties investigated. Thermal and electrical conductivity of graphitized carbon materials increase with the pyrolysis temperature, indicating a relationship between the degree of graphitization and thus in crystallite size with transport properties in the resulting carbon scaffolds. Evaluation of the experimental results indicate that thermal conductivity is mainly through phonons and decreases with the temperature in Fe-catalyzed carbons suggesting that due to defect scattering the mean free path of phonons in the material is small and defect scattering dominates over phonon-phonon interactions in the range from room temperature to 800ºC.

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ABSTRACT:We report here on controlled synthesis, characterization and electrochemical properties of different polymorphs of niobium pentoxides grown by CVD of new single-source precursors. Nb2O5 films deposited at different temperatures showed systematic phase evolution from low-temperature tetragonal (TT-Nb2O5, T-Nb2O5) to high temperature monoclinic modifications (HNb2O5). Optimization of the precursor flux and substrate temperature enabled phase-selective growth of Nb2O5 nanorods and films on conductive mesoporous biomorphic carbon matrices (Bio-C). Nb2O5 thin films deposited on monolithic mesoporous biomorphic carbon (Bio-C) scaffolds produced composite materials integrating the high surface area and conductivity of carbonaceous matrix with the intrinsically high capacitance of nanostructured niobium oxide. Hetero-junctions in Nb2O5/BioC composites were found to be beneficial in electrochemical capacitance. Electrochemical characterization of Nb2O5/BioC composites showed that small amounts of Nb2O5 (as low as 5%) in conjunction with Bio-C resulted in a seven-fold increase in the electrode capacitance, from 15 to 104 F g -1 , making these materials ideally suited for electrochemical energy storage applications.