Preparation and regeneration of supported single-Ir-site catalysts by nanoparticle dispersion via CO and nascent I radicals

Heterogeneous single-metal-site Ir catalyst (Ir1/AC, 5 wt%) was prepared from the in-situ atomic dispersion of corresponding supported nanoparticles on activated carbon (Ir/AC), by the thermal treatment with CO and CH3I. The physical coordinated structure of those single-metal-site Ir catalysts were determined by HAADF-STEM and EXAFS. The key species, I radicals for this process were creatively detected by photoelectron photoion coincidence spectroscopy with vacuum ultraviolet synchrotron radiation in swiss light source. Our findings provide an alternative approach to prepare the supported atomically dispersed single-metal-site catalyst, which have the analogically homogeneous structure and show a comparable catalytic activity as homogeneous catalyst for methanol carbonylation. More importantly, 5 wt% Ir1/AC catalyst, deactivated by metal atoms agglomeration can be regenerated repeatedly with the thermal treatment of CO and CH3I to regain their initial activity for heterogeneous methanol carbonylation. General speaking, we provide a method of preparation and regeneration of supported single-metal-site catalyst, which has broad application, especially for the regeneration of supported sinter and agglomerated catalyst.