The Roles of Precursor-Induced Metal-Support Interaction on the Selective Hydrogenation of Crotonaldehyde over Ir/TiO2 Catalysts

Various supported Ir/TiO2 catalysts were prepared using different Ir precursors (i.e., H2IrCl6, (NH4)(2)IrCl6 and Ir(acac)(3)) and tested for vapor phase selective hydrogenation of crotonaldehyde. The choice of Ir precursor significantly altered the Ir-TiOx interaction in the catalyst, which thus had essential influences on the geometric and electronic properties of the Ir species, reducibility, and surface acidity, and, consequently, their reaction behaviors. The Ir/TiO2-N catalyst using (NH4)(2)IrCl6 as the precursor gave the highest initial reaction rates and turnover frequencies of crotyl alcohol formation. Such high performance was ascribed to the high Ir dispersion and high surface concentration of Ir-0 species, as well as a higher surface acidity, in the Ir/TiO2-N catalyst compared to its counterparts, indicating the synergistic roles of the Ir-TiOx interface in the reaction, as the interfacial sites were responsible for the adsorption/activation of H-2 and the C=O bond in the crotonaldehyde molecule.

Automated summary

In this study, various supported Ir/TiO2 catalysts were prepared using different Ir precursors and tested for vapor phase selective hydrogenation of crotonaldehyde. The choice of Ir precursor significantly altered the interaction between Ir and TiOx in the catalyst, thus affecting the catalyst's performance.