Strong metal-support interaction assisted redispersion strategy for obtaining ultrafine and stable IrO2/Ir active sites with exceptional methane oxidation activity

Skillful arrangement of the active sites with stable dispersion and desired chemical states on the support surface is vital for their powerful application in catalysis, but remains a daunting challenge. Herein, we present a unique redispersion strategy for well dispersing and stabilizing IrO2/Ir active sites over TiO2 as an advanced catalyst for low temperature CH4 oxidation. The as-designed Ir/TiO2 with a 1 wt.% Ir loading amount exhibits a (>)99 % CH4 conversion and excellent durability at a temperature as low as 320 degrees C, which ranges among the best of state-of-the-art methane combustion catalysts. Various characterizations and DFT calculations were performed to reveal the redispersion mechanism and understand the reason for the enhanced performance. The superior performance is related to the proper chemical state of complex IrO2/Ir active sites and their ultrafine and stable dispersion, all relating to the strong metal-support interaction (SMSI) induced redispersion process. Such SMSI assisted active sites redispersion strategy provides useful guidance for the rational design of efficient Ir-based and other noble metal catalysts.

Automated summary

The study presents a unique redispersion strategy to well disperse and stabilize IrO2/Ir active sites on TiO2 as an advanced catalyst for low temperature CH4 oxidation. The catalyst shows excellent performance with high conversion rates and durability at low temperatures, and is among the best methane combustion catalysts available. This SMSI-assisted active site redispersion strategy provides useful guidance for the rational design of efficient Ir-based and other noble metal catalysts.