Valorization of waste tire granules for the production of tetrahydrofuran to furan dehydrogenation catalysts

The valorisation of end-of-life tire (ELT) waste remains a major environmental challenge. This work proposes a waste-to-value strategy to reintegrate ELTs into production cycles, in line with circular economy principles, through the production of carbonaceous materials suitable as catalytic supports. After optimising the preparation procedure, two 1 wt% Pd catalysts were synthesised using supports treated with different sulphuric acid concentrations: Pd/ELT-1 M and Pd/ELT-18.4 M. These catalysts were evaluated in the dehydrogenation of tetrahydrofuran (THF) to furan (FUR), a reaction that can be considered a model for oxygenated liquid organic hydrogen carriers (LOHCs). Moreover, both compounds can be derived from renewable resources. The acid treatment was found to significantly influence both the morphology and surface chemistry of the supports, leading to marked differences in catalytic performance. Pd/ELT-1 M exhibited measurable activity, increasing within the 200–300 °C range, and achieved near-complete selectivity to FUR at 350 °C, whereas Pd/ELT-18.4 M remained inactive. This selectivity behaviour is attributed to the sulphur content of the ELT-derived support, as sulphur species may adsorb on non-selective catalytic sites, leading to their partial deactivation and thus enhancing selectivity by suppressing undesired side reactions. This behaviour contrasts with that observed for a commercial Pd/C catalyst. Overall, this work demonstrates the potential of waste tire-derived carbon materials as sustainable catalytic supports, contributing to waste valorisation and offering perspectives for their application in hydrogen storage and on-site hydrogen supply systems.