On the Applications as Catalytic Support of Biochars Obtained by Pyrolysis of Waste Biomasses

Biochars, as carbon rich materials with tuneable properties and a chemical composition of various doping and functionalized elements, are a promising option for many different applications. In this work, biochars were obtained by pyrolysis of different biomasses from vegetal (hazelnut shells, vine wood waste, barley waste, rice husks, and Sargassum, macroalgae of Venetian lagoon) and animal (leather tannery waste) origins. The activation was performed either by CO2 or steam physical treatment at high temperature. Biochars and activated biochars were characterized by elemental analysis, N2 physisorption, and FTIR techniques. The chemical, morphological, and textural properties of the biochars were strongly affected not only by the origin of the starting biomass, but also by pyrolysis conditions and activation parameters. Some examples of applications of these activated biochars as support for different metal catalysts in biomass valorisation reactions will be presented. In particular, the following samples were investigated: i) Ru/C catalysts for the hydrogenation of 5-hydroxymethylfurfural. ii) Pd/C catalysts for benzaldehyde hydrogenation to toluene. iii) Ni/C catalysts for the conversion of levulinic acid to γ-valerolactone. The catalytic performances were discussed comparing the prepared samples with commercial references. It can be postulated that biomass wastes properly treated with pyrolysis can not only be recycled but also upgraded.