May 20, 2022
14h00
Auditoire LAVO51, Place Louis Pasteur
Bifunctional catalysts for the valorization of cellulose into sorbitol
The aim of this PhD thesis was to elaborate a bifunctional catalyst that would allow biomass valorization, namely converting cellulose into sorbitol.
The first part of this work was devoted to the study of glucose hydrogenation into sorbitol. Catalysts composed of Ru nanoparticles deposited on carbon supports have been synthesized. Different sizes of Ru nanoparticles were prepared and the optimal size for this reaction has been established between 1 and 2 nm. Moreover, doping of carbon materials with nitrogen atoms has also been investigated. Efficient functionalization was confirmed by X-ray photoelectron spectroscopy and Boehm titration. Enhancement of the Ru activity by the presence of nitrogen in the support has been demonstrated for the direct transformation of cellobiose (two glucose units bound together) into sorbitol.
The second part of this thesis was dedicated to the study of cellobiose hydrolysis into glucose. Several carbon materials have been successfully covalently functionalized with sulfonic functions by a diazonium coupling method. Functionalized carbons displayed excellent acidity (confirmed by Boehm titration) and showed great selectivity in glucose as main hydrolysis product.
The last part of this manuscript dealt with the synthesis of bifunctional catalysts composed of Ru nanoparticles deposited on carbon supports functionalized by sulfonic functions. Despite cross-poisoning between the two active sites, optimization of the ratio between Ru and sulfur led to a bifunctional catalyst that outperformed non-acidic Ru/C catalysts. Sorbitol has been produced from cellobiose and more importantly from cellulose, in significant amounts compared to literature standards, with this bifunctional catalyst.
Jury members :
- Prof. Sophie Hermans (UCLouvain), supervisor
- Prof. Eric Gaigneaux (UCLouvain), chairperson
- Prof. Tom Leyssens (UCLouvain), secretary
- Prof. Patricia Luis Alconero (UCLouvain)
- Dr. Robert Wojcieszak (Université de Lille, France)
- Dr. Vincent Dubois (LABIRIS, Belgium)