Oxidation behavior at moderate temperature under dry and wet air of phenolic resin-derived carbon

Abstract

International audienceThe oxidation behavior of carbon materials has been investigated at temperatures less than 773 K using isothermal thermogravimetric analyses under dry and wet air. Bulk samples obtained by the pyrolysis of phenolic resin have been characterized using X-ray diffraction and elementary analysis. X-ray photoelectron spectroscopy and Raman spectroscopy have been performed to analyze the surface and subsurface. The carbon structure has a poor organization state and a gradient in the oxygen concentration and structure between the surface and the bulk is revealed. The material is more reactive under wet air than dry air in terms of oxidation rates as determined between 623 and 773 K. The apparent activation energies are respectively 122 ± 6 kJ/mol in dry air and 102 ± 6 kJ/mol in wet air

The Improvement of Degradation Strength of aAlkyd Resin EZ 528 Used in Rotating Machines

“…The evident effect of protection activity of Ce-doped lead zirconate is the delay of ageing in the favor of recombination through which the gelation occurs. This contribution was already reported for other type of materials, which are subjected to an accelerated process of degradation [20,21].…”

Identification of Complex Oxidation/Corrosion Behaviours of Boron Nitride Under High Temperature

“…This model seems to properly explain the differences encountered with the theoretical paralinear model. Such a kind of behaviour has already been observed for oxidation in air of poorly crystallized carbon (phenolic resin-based carbon): similar layered crystalline structure, sensitive to adsorption and/or intercalation phenomena [10,11].…”

Preoxidation-assisted nitrogen enrichment strategy to decorate porous carbon spheres for catalytic adsorption/oxidation of methyl mercaptan

“…The results can be probably attributed to the partial collapse of some pore walls or the recession of some pore channels by the reaction related to O 2 , and eventually some micropores or/and mesopores became expanded or collapsed in different extent, resulting in the decrease of micropore volume. 39,40 However, when the preoxidized carbon spheres are subjected to the ammonia thermal treatment under 800 C, the oxygen surface groups rstly give rise to decomposition that creates the vacant Table 1 Porous structure parameters of the samples a sites in the pores, which provide more opportunities to increase reaction probability with created free radicals under the simultaneous ammonia treatment at 800 C. It has been also reported that gasication with ammonia has a protable to recover its porosity blocked by preoxidization, and increase the porous structure parameters over that of the oxidized sample. 41,42 Moreover, the carbon spheres (ACSON) obtained by the preoxidation-assisted ammonia thermal treatment show bigger BET surface, total pore volume and microporous volume than those of the direct oxidized carbon spheres.…”

“…2(e), although it maintains good sphericity. The phenomenon can be attributed to the synergistic effect of thermal air oxidation and ammonia etching action, 37,39 in which the surface oxygen functional groups to create vacant sites through thermal decomposition, and free radicals (NH 2 , NH and H) react with these vacant sites or surface oxygen functional groups to develop pore structure, leading to the increase of BET surface area and pore volume and simultaneously the introduction of nitrogen containing functional groups in the ACSON. On the contrary, CACS from commercial activated carbon is very different, the exterior surface shows some big cracks with roughness in Fig.…”

“…In our study, the resin spheres was rstly activated by steam under 850 C, and then the obtained carbon spheres were treated with thermal air, in which the diffusion and etching action appeared between the oxygen molecules and the carbon surface or pore channel of activated carbon spheres under 350 C, including CO 2 departure, pores expansion or collapse, and the formation of new oxygen containing groups, nally leading to the increase of oxygen containing groups, especially the oxygen content of the oxidized carbon spheres. 25,39 Furthermore, the virgin and oxidized carbon spheres were separately treated by ammonia thermal treatment, and the reactions between the created free radicals during ammonia decomposition and the surface of carbon spheres considerably introduced nitrogen into the carbon structure. For example, the nitrogen content increased to 5.21 wt% and 7.13 wt% for ACSN and ACSON compared with the ACS (0 wt%), respectively.…”