Operando CO Infrared Spectroscopy and On-Line Mass Spectrometry for Studying the Active Phase of IrO<sub>2</sub> in the Catalytic CO Oxidation Reaction
oleh: Phillip Timmer, Tim Weber, Lorena Glatthaar, Herbert Over
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2023-02-01 |
Deskripsi
We combine operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) with on-line mass spectrometry (MS) to study the correlation between the oxidation state of titania-supported IrO<sub>2</sub> catalysts (IrO<sub>2</sub>@TiO<sub>2</sub>) and their catalytic activity in the prototypical CO oxidation reaction. Here, the stretching vibration of adsorbed CO<sub>ad</sub> serves as the probe. DRIFTS provides information on both surface and gas phase species. Partially reduced IrO<sub>2</sub> is shown to be significantly more active than its fully oxidized counterpart, with onset and full conversion temperatures being about 50 °C lower for reduced IrO<sub>2</sub>. By operando DRIFTS, this increase in activity is traced to a partially reduced state of the catalysts, as evidenced by a broad IR band of adsorbed CO reaching from 2080 to 1800 cm<sup>−1</sup>.