NITROGEN DOPED CARBONS BY CO-PYROLYSIS OF LDPE AND DIFFERENT NITROGEN SOURCES: CHARACTERIZATION AND CATALYTIC ACTIVITY IN HYDROTREATMENT

摘要

Doped carbon materials have atracted attention in the last years due to the excellent properties that they can exhibit for specific aplications, such us electrochemical ones and catalysis. The properties of N-doped carbons (NDCs) release from their particular electronic configuration of the graphene p system and nitrogen atoms. The presence of nitrogen, as doping agent, lead to n-type-structures with excess of electrons in the carbon network. The electronic properties of NDCs depend on the type of bonding that is established between nitrogen and carbon atoms [1,2]. Chemical vapor deposition is one of the most common methods to obtain these carbons. In this technique the carbon precursor is co-pyrolysed with the nitrogen sources to obtain the NDCs. The literature is wide in combinations of carbon precursors and nitrogen sources. Ethanol, toluene, bencene, xylene, tiophene and ethylene are the most common carbon sources employed [3,4]. The variety of nitrogen compounds is also high, being ammonia, etilendiamine, aniline, benzylamine, pyridine, among them [1, 5]. Although the carbon nanotubes is,the morphology most studied of the NDCs, other morphologies such as nanospheres, xerogels and graphenes have been also studied [6]. NDCs have been evaluated mainly for gas storage, adsorption, energy storage, catalytic oxidation and fotocatalisis. In the current work, low-density polyethylene (LDPE) has been studied in order to obtain NDCs by co-pyrolysis with different nitrogen sources. The influence of different pyrolysis conditions on nitrogen content of the carbons has been. evaluated. These carbons have been used as catalysts and catalytic supports in the hydrodechlorination (HDC) of 4-chlorophenol (4-CP) in aqueous phase.