Pd supported on defective TiO2 polymorphic mixtures: Effect of metal-support interactions upon glycerol selective oxidation

RINAUDO, M.G.; ANA MARIA BELTRÁN; MARÍA ASUNSIÓN FERNÁNDEZ; LUIS E. CADÚS; MARÍA ROXANA MORALES

Results in Engineering

Elsevier

Año: 2022 vol. 16 p. 100737 - 100751

2590-1230

Palladium catalysts supported on defective mixes of anatase, TiO2 (II) and rutile crystalline phases, previouslyobtained by high-energy ball milling, were synthesized and tested for glycerol selective oxidation. A deepcharacterization of these unusual materials was carried out to elucidate catalytic and physicochemical features.Electron density transfer from support to metal or vice versa, depending on the polymorphs present, could notonly alter palladium particle sizes and its surface oxidation state but also reducibility and oxygen mobility ofcatalysts. Furthermore, acid-base properties achieved also influenced catalytic activity under mild conditions ofliquid-phase glycerol oxidation. A conversion of 94% and a selectivity to glyceric and lactic acids of 48% and22% respectively were obtained for the Pd catalyst supported on mechanochemically activated anatase. Thepresence of several polymorphs in a metal oxide support could therefore benefit or handicap catalytic cycle for aparticular reaction. Metal-support interactions play a key role in heterogenous catalysts and thus the rationaldesign of supports comes on the scene.