Exploring the key components of Au catalyst during CO oxidation using TG-MS and operando DRIFTS-MS

Nano-Au has a good catalytic activity for CO oxidation, but its catalytic mechanism is still not clear. Here, CO oxidation on Au 2 O 3 and its thermal decomposition products were studied using thermogravimetric-mass spectrometry (TG-MS) and operando diffuse reflectance infrared Fourier transform spectroscopy-mass spectrometry (DRIFTS-MS) to explore the key active components of Au catalyst for CO oxidation. The TG-MS results showed that Au 2 O 3 decomposed to AuO at 210 °C and Au at 375 °C and was oxidized to form Au oxide above 375 °C. When Au 2 O 3 decomposed into Au x O y (x>y) above 210 °C, the CO oxidation activity obviously increased. Au atoms in the Au-Au system serve as electron donor and CO adsorption sites. Au atom is oxidized to AuO by the O atom from O 2 decomposition following the Epling-Xu decomposition mechanism. A schematic diagram of the key components of Au 2 O 3 catalysts during CO oxidation was proposed based on TG-MS and operando DRIFTS-MS analysis results.