EXAFS studies to determine the role of support on IrReOx catalysts for CO hydogenolysis of polyols

MARÍA EUGENIA SAD; EMANUEL VIRGILIO; CRISTINA PADRÓ; ARMANDO BORGNA

San Diego, California

Congreso; 17th INTERNATIONAL CONGRESS ON CATALYSIS; 2020

NACS

Selective C-O hydrogenolysis de polyols is an important strategy to remove thehydroxyl groups of these oxygenated biomass-derived molecules. It has been studied oversupported noble metal such as Pt, Ru, Rh, and Ir. In order to prevent the break of the carbonchain an oxophilic promoter (Re, Mo or W) is added resulting in an improvement of theselectivity to the C-O cleavage. Erythritol (ERY, C4H10O4), a polyol produced by fermentation of sugars can be converted to valuable butanediols (BDOL) by CO hydrogenolysis. However, consecutive hydrogenolysis produces butanols and butane, while C-C cleavage leads to C2-C3 products, which are less valuable and, therefore, should be avoided. High yield (35 %) of BDOL from ERY, has been reported on IrReOx/SiO2 [1]. Due to the low hydrothermically stability of SiO2 other supports as ZrO2, TiO2 or Carbon can be also employed. The C-O scission are assumed to proceed on the interface between noble metal and metal oxide that is partially reduced, becoming necessary the study of metallic species that are active to catalyze the desired reaction path. In this sense, Amada, et al.[2] have investigated the structural changes on IrReOx/SiO2 during reduction by in situ XAFS, and have proposed the formation the Ir metal particles covered with three-dimensional low valent (II) ReOx clusters after reduction at 485-595 K. Therefore, the aim of our work is to elucidate the effect of the properties of the support on the mechanism of formation of ReOx species attached on Ir metal surface in order to get, a model structure identifying the catalytic active site for selective BDOLs formation from ERY.