Efficient valorization of CO2 into formate through nanocatalysis

Identifier:  TDX:4659

Handle: https://hdl.handle.net/20.500.11797/TDX4659

Authors:  Fernández Martínez, María Dolores

Abstract:
In the present Thesis, the state-of-the-art catalysts for the hydrogenation of CO2 into formate are described in details. The preparation and characterization of a series of ligand-capped supported Pd nanoparticles using a simple procedure and their application as catalysts in the hydrogenation of CO2 to formate are described. PPh3 revealed the most appropriate stabilizing ligand while TiO2 was the most efficient support for these catalysts. Also, the preparation of supported Pd-NPs based materials were is described using modifiers of different nature (APTES, ILs and PAs) and following two distinct approaches: the so-called reverse deposition approach that requires to modify the TiO2 support in the first place prior to Pd NPs deposition while the 2nd approach consisted in the modification of the pre-synthesized Pd-PPh3/TiO2, by deposition of the modifier over its surface. These catalysts were used in the hydrogenation of CO2 to formate, the modification of the TiO2 support by organosilanes provided a beneficial effect in catalysis compared with the catalyst containing unmodified TiO2 or TiO2 modified by organophosphonic acids. In terms of recyclability, some of the materials where the modifiers were deposited over the previously anchored Pd NPs onto TiO2 showed a much more gradual decrease in activity. DFT calculations were also carried out to get insights into the reaction mechanism using some of these catalysts.