In situ electron paramagnetic resonance (EPR) study of surface oxygen species on Au/ZnO catalyst for low-temperature carbon monoxide oxidation Original Research Article

Some paramagnetic superoxide ions detectable by electron paramagnetic resonance (EPR) can be generated on Au/ZnO catalyst by oxygen adsorption at room temperature as well as at 553 K. In both the cases, the O2− ions are present on the catalyst surface. The disappearance of the O2− signal by the introduction of carbon monoxide over the catalyst surface implies that the O2− ions are either the active oxygen species or the precursors of the active oxygen species. The CO3− species produced are also detected by EPR.