Preparazione di elettrocatalizzatori 3D a base di Ag per la riduzione del 5-idrossimetilfurfurale

Electrochemical reduction of the 5-hydroxymethylfurfural (HMF) - a biomass derived platform molecule to 2,5-bis (hydroxymethyl)furan (BHMF) - monomer for the manufacture of polyurethane foams or polyesters - is one promising alternative to the conventional hydrogenation since it is carried out at room temperature and using H+ or H2O as hydrogen suppliers, thus avoiding high pressure H2 source. In this work, we propose the use of Ag-supported copper open-cell foams to replace conventional 2D electrodes, which integrate the highly active performance of Ag nanoparticles with high geometrical surface area, mass and electron transfer of Cu open-cell foam creating a highly active 3D electrode for the reduction of HMF into BHMF. The aim of the thesis is twofold: i) preparation of the Ag-supported Cu foam electrodes by galvanic displacement; ii) optimization of the electroreduction parameters. In the first part, the synthesis conditions are optimized based on three important parameters, namely the concentration of AgNO3, synthesis time, and stirring during the galvanic displacement as well as a combination with electrodeposition or multiple displacements. In the second part, the electrochemical reactions taking place are investigated (HMF and water reduction) to obtain not only high HMF conversion/BHMF selectivity but also high Faradaic efficiency. Moreover, a study about the effect of stirring rate (0 – 1000 rpm), HMF concentration (0.02 – 0.10 M), total charge transfer (up to 110 C), and electrode size (0.8 - 1.6 cm2) on the performances is carried out. The best catalyst exhibits a 99 % conversion of HMF with 99 % selectivity in BHMF and 93 % Faradaic efficiency in 0.02 M HMF. The catalyst is promising since it is quite stable after 9 cycle tests.