Cux/ZnO-y catalysts. Effect of support modification by high energy milling on the metal-support interaction

MARIA KARLA LOPEZ GONZALEZ; LUIS E. CADUS; M. ROXANA MORALES

Congreso; 1st International Electronic Conference on Catalysis Sciences Section:Catalyst Synthesis and Characterization; 2020

Commercial ZnO was subjected to high-energy milling to introduce structuralmodifications, which can result in a different metal-support interaction. The milling time (0 to 960min) and vial material and mill balls (WC and ZnO2), were modified. The supports werecharacterized by XRD, Scherrer, SBET and Raman Spectroscopy. With the increase in milling time, anincrease in the accrued kinetic energy (Ecum) was observed. For the same Ecum, with ZrO2, twice thearea was obtained in just 6 min. Cu was deposited on both, the milled support (ZnO-z) and unmilledsupport (ZnO-0) in three compositions; x = 0.2, 0.5, and 1.0 (%wt). Atomic Absorption Spectroscopy(AAS) measurements showed Cu compositions similar to the theoretical ones. XRD studies, Rietveldmodelling and Raman Spectroscopy confirmed that Cu2+ cations could be localized, either bysubstituting the Zn2+ ions or interstitially in the network, depending on the metal content. The TPRprofiles showed two types of copper species, which interact differently with the support. Likewise,the analysis of the XPS results showed that, with the increase in Cu content, for Cux/ZnO-0, there isa decrease in the metal-support interaction. However, for Cux/ZnO-z the interaction increases,which can be associated with the introduction of structural defects accompanied by superficialenergy changes. For both systems, different catalytic behaviours are expected in the hydrogenolysisreaction of glycerol in liquid phase, regarding selectivity and stability, as a result of the metalsupportinteraction achieved.