Relazione Scientifica CNR-ITAE, Messina Accordo di cooperazione scientifica tra CNR e HAS (MTA) (Ungheria)

The aim of this research activity is focused towards the study of reaction mechanism of the CO2 hydrogenation to dimethyl ether (DME) reaction in the presence of novel hybrid catalysts. The analytical methodology exploited to achieve this target is based on the use of operando spectroscopic method, in which the spectroscopic characterization of the materials could be coupled simultaneously with the evaluation of the activity-selectivity model under the real reaction conditions. Therefore, the aim of the research activity is to individuate the nature and the functionality of surface adsorption sites, determine the intermediate compounds formed and evaluate how the CO2 is activated on Cu-zeolite based catalysts to be then converted to DME in order to further optimize the formulation and the design of the solid Cu-based catalysts. The surface species formed during the reaction should be identified by the operando DRIFT, while the chemical state of species present on the surface of both the fresh and used catalysts and their modifications due to the reaction mixture should be evaluated by exploiting in situ XPS measurements. At the same time, the chemico-physical characterization of catalytic systems developed using traditional ex situ methods (BET measurements, chemisorption, TEM/SEM, XRD, XPS) will be useful to support the results obtained. Thereby, it will be possible to establish fundamental structure-reactivity correlations of the hybrid catalysts investigated and therefore to obtain decisive information on the mechanism of direct hydrogenation of CO2 to DME. The project purposes also include an improvement in the design of nano-hybrid materials, along with the improvement of existing catalytic processes and the development of new ones. Specifically, the attention during this first year has been focused at exploiting the potential of DRIFT in operando mode to study the reaction mechanism and the nature of active site in CO2 hydrogenation reaction to DME, the measurements being carried out under the real reaction conditions by using a CO2/H2 mixture, in the temperature range of 180-260°C under pressure (10-50 bar) in presence of a Cu ZrO2/Ferrierite catalyst.