Highly dispersed silica-supported iridium and iridium-aluminium catalysts for methane activation prepared via surface organometallic chemistry

The grafting of an iridium-aluminium precursor onto silica followed by thermal treatment under H-2 yields small (<2 nm), narrowly distributed nanoparticles used as catalysts for methane H/D exchange. This Ir-Al/SiO2 catalyst demonstrated enhanced catalytic performances in comparison with the monometallic Ir/SiO2 analogue (TOFs of 339 h(-1)versus 117 h(-1) respectively), highlighting the promoting effect of aluminium. TON up to 900 is obtained after 9 hours, without evidence of catalyst deactivation, and identical performances are achieved after air exposure, underlining the good robustness of both Ir-Al/SiO2 and Ir/SiO2 catalytic materials.