Copper catalysts supported on ordered and disordered silica–carbon composites for NOX elimination

Abstract

Copper catalysts supported on two types of silica–carbon composites- with ordered and with disordered architecture were investigated in reactions of NOx elimination. Disordered silica-carbons were prepared by sol–gel method and ordered composites by tri-constituent co-assembly of resol, silica oligomers and triblock copolymer. Two Si/C ratios were applied for the preparation of both series of composites. The copper active phase was deposited by the incipient wetness technique with subsequent vacuum evaporation and thermal treatment. The catalysts were characterized by low-temperature nitrogen adsorption, X-ray diffraction, atomic absorption spectroscopy, transmission electron microscopy, thermal analysis, X-ray photoelectron spectroscopy. The catalytic performance in NO reduction with CO and in N2O decomposition up to 300 °C was tested. It was found that the activity in NO reduction depends on the copper content on the surface and on its oxidation state. The specific activity in N2O elimination does not depend on the nominal copper content of the samples but on the ratio Cu+/Cu2+ and on the surface carbon. In this case carbon plays a role not only of a support but also of a reactant.