Valorization of carbonaceous co-product obtained from iron ore-catalyzed methane cracking as support for Pd catalysts in toluene hydrogenation reaction

Iron ore has been proven as an abundant and sustainable catalyst in the production of hydrogen by catalytic cracking of methane. One of the main challenges is the identification of suitable market niches for the utilization of the resulting iron-carbon hybrid in order to make this process economically viable. This study examines the feasibility of using the iron-carbon hybrid obtained from methane cracking as support of Pd catalysts for the hydrogenation of toluene (350 ºC, 35 bar of H2 at room temperature and 90 min). Before supporting Pd, Fe-C hybrid was subjected to different acid functionalization treatments (nitric and/or phosphoric acids). The results indicate that sequential oxidation with nitric acid, followed by phosphoric acid, is the most effective strategy for achieving the highest catalytic activity (1294 mmolToluene gPd⁻¹) and conversion (27 %). Toluene conversion was 1.8 and 14.2 times higher than with the catalysts treated with nitric and phosphoric acid separately. Therefore, this work proves the possibility of employing carbon/Fe hybrid materials obtained in iron ore catalyzed methane cracking as catalytic supports in industrial relevant reactions. [Display omitted] •Pd nanoparticles are highly dispersed after HNO3 physical treatment.•Phosphoric acid treatment on carbon materials improved Pd dispersion.•Hydrogenation is enhanced after the sequential acid treatments.•Hydrogenation reaction is greatly affected by the Pd dispersion.