New efficient Cu-SiO2 catalysts made by Aerosol Assisted Sol-gel method for the ethanol non oxidative dehydrogenation reaction

Nowadays, bioethanol is considered a crucial primary platform chemical [1]. One of the most important intermediates that can be obtained from bioethanol is acetaldehyde, that allows producing several other important industrial chemicals [2]. Acetaldehyde can be produced through non-oxidative dehydrogenation of bioethanol. For this reaction, copper-based formulations such as Cu-ZnO-Al2O3, Cu-MgAl2O4, Cu-SiO2, Cu-Al2O3 have been widely studied in literature [3-5]. These studies showed a strong impact of the preparation procedure on catalyst performances. In particular, it is crucial to precisely control the active site speciation and catalyst texture. This prompted us to study the potential of the Aerosol-Assisted Sol-Gel process (AASG) for the preparation of efficient ethanol dehydrogenation catalysts. Aerosol processes are currently emerging as promising synthetic routes to synthesize supported catalysts controlling active site dispersion and porosity [6]. Based on the atomization and fast drying of a precursor’s solution or suspension, this bottom-up technique allows the one-step and continuous production of tailored nanomaterials. Interestingly, to the best of our knowledge no one still used this process to synthesize active catalysts in ethanol non oxidative dehydrogenation. Thus, the present work aims at exploiting AASG technique to prepare Cu-SiO2 catalysts for bioethanol dehydrogenation, comparing their catalytic performances with conventional impregnated Cu/SiO2 catalyst. Furthermore, the effect of the Cu loading and of synthetic procedure on the catalyst performances were investigated and a deep characterization of fresh and used catalysts were carried out. These catalysts show excellent catalytic performances, up to 76% acetaldehyde yield with selectivity higher than 95%, with higher dispersion of the active phase and more resistance to Cu coalescence respect to the impregnated ones