Mechanistic Aspects of Wet and Dry CO Oxidation on Co 3 O 4 Nanorod Surfaces: A NAP-UPS Study

Catalytic activity, electronic structure, and the mechanistic aspects of Co O nanorod (NR) surfaces have been explored for CO oxidation in dry and wet atmosphere using near-ambient pressure ultraviolet photoelectron spectroscopy. Presence of water with CO + O plummets the catalytic activity because of the change in the electronic nature from predominantly oxide (without water in feed) to a Co O surface covered by a few intermediates. However, at ≥375 K, the Co O surface recovers and regains the oxidation activity, at least partially, even in the presence of water. This is fully supported by the changes observed in the work function of Co O under wet (H O + CO + O ) conditions compared with dry (CO + O ) conditions. This study focuses on the comparative CO oxidation rate on Co O NR surfaces and highlights the changes in the electronic structure that occur in the catalyst during the CO oxidation reaction.