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

Abstract

The grafting of an iridium–aluminium precursor onto silica followed by thermal treatment under H₂ 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⁻¹versus 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.