Ir catalysts supported on ZrO₂ were prepared by an impregnation method, and their catalytic performance for CH₄ catalytic combustion were tested. The catalyst structure and Ir species in the catalyst were characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and H₂ temperature programmed reaction (H₂-TPR) techniques. The results showed that Ir existed in the form of IrO₂ in the Ir/ZrO₂ catalysts. The apparent activity of Ir/ZrO₂ catalysts for CH₄ combustion increased with Ir loading, and the catalysts showed high activities as well as good stability. Turnover frequency (TOF) for CH₄ combustion increased with Ir particle size with low Ir loading (≤1%), however, it remained constant with high Ir loading (≥1%).

Key words: Ir/ZrO₂ catalyst, methane, catalytic combustion