Remarkable Activity of Nanoarchitectonics Mesoporous CuO/CeO₂-TiO₂ Prepared by Nanocasting and Deposition Precipitation Techniques.

Abstract

In this work, a ceria (CeO₂) support was modified with titania (TiO₂) by nanocasting using MCM-48 as a hard template and then loading Cu (as the nitrate salt) at different levels (3-9% by weight) by deposition-precipitation followed by calcination. The addition of TiO₂ in MSP CeO₂ revealed that the MSP CeO₂ was significantly improved the oxygen vacancies of the catalyst by increasing the Ce3+ content from 38 to 75% and stabilizing the Ce3+ species by bonding with the oxygen as Ce(4f)-O(2p)-Ti(3d). Moreover, the bonding of MSP CeO₂ with TiO₂ generated the oxygen defect vacancies (s-Ti3+), allowing Cu2+ to occupy and be reduced to Cu+ during calcination. The smaller CeO₂ crystallite size (2.7 nm) of 9Cu/CeO₂-TiO₂ increased the mass-specific CO-Oxidation, showing the best catalytic activity due to its highest redox properties, as determined by H₂-TPR and also showing resistant property to water and carbon dioxide. Indeed, water was adsorbed on the Ce3+ sites, generating OHads which reacted with CO to form -COOH, resulting in CO₂.