Platinum catalysts supported on MWNT for liquid phase degradative oxidation of nitrogen containing compounds

Since their discovery [1], carbon nanotubes (CNT) have attracted great interest from both a fundamental and an applied point of view, due to their high mechanical strength and unique electrical and thermal properties [2]. These characteristics are also interesting in the context of using CNT as a support for heterogeneous catalysts in liquid-phase reactions. Some examples of this type of application using multiwalled carbon nanotubes (MWNT) have been reviewed recently [3]. Our experience with carbon supported noble metal catalysts applied to catalytic wet air oxidation (CWAO) of liquid effluents [4] prompted us to prepare platinum catalysts supported on surface oxidized MWNT, to be used in the liquid phase degradative oxidation of nitrogen containing compounds, such as aniline and azo dyes. The catalysts Pt1, Pt2 and Pt3 were prepared by excess solution impregnation, using different metallic precursors dissolved in various solvents, respectively [PtI2(CO)2] in toluene, H2PtCl6 in water and [Pt(CH3)2(C8H12)] in hexane. The metal dispersion (DM) was determined by H2 pulse chemisorption (Table 1). The prepared catalysts were then tested in the CWAO of aniline. The aniline conversion (XAniline), TOC abatement (XTOC) and selectivity towards CO2 formation (SCO2) obtained after 2 h of reaction at 200ºC and 6.9 bar of oxygen partial pressure are resumed on Table 1