Structure and performance of supported iridium catalyst for the lean methane oxidation at low temperature

To clarify the relationship between the structure and performance for the Ir-based catalysts, a series of Ir/SiO2 catalysts were prepared by the colloid-impregnation method and evaluated in the lean methane oxidation at low temperature. The results indicate that the colloid-impregnation is effective to attain highly dispersed Ir nanoparticles on the SiO2 support. The catalytic activity of Ir/SiO2 is sensitive to the structure and state of loaded Ir species; the Ir/SiO2 catalyst with abundant defective Ir3+ species and mean Ir particle size below 2.0 nm exhibits extraordinarily high activity in methane oxidation. However, the activity of Ir/SiO2 decreases considerably with the increase of calcination temperature, due to the agglomeration of Ir particles induced by high temperature. Nevertheless, the thermal stability of supported Ir catalysts can be greatly improved by employing proper support with strengthened metal-support interaction, suggesting the enormous potential of supported Ir catalysts in the related applications.

Automated summary

This study investigates the relationship between the structure and performance of Ir-based catalysts. It was found that the catalytic activity of the Ir/SiO2 catalysts is influenced by the structure and state of the loaded Ir species. Additionally, the thermal stability of supported Ir catalysts can be improved by using a suitable support.