Pt-based catalysts exhibit unique catalytic properties in many chemical reactions. In particular, metal-support interactions (MSI) greatly improve catalytic activity. However, the current MSI mechanism between platinum (Pt) and the support is not clear enough. In this paper, the interaction of 1 wt% Pt nanoparticles (NPs) on β-MnO2 in carbon monoxide (CO) oxidation was studied. The Pt on β-MnO2 inhibited CO oxidation below 210 °C but promoted it above 210 °C. A Pt/β-MnO2 catalyst contains more Pt4+ and less Pt2+. The results of operando DRIFTS-MS show that surface-terminal-type oxygen (M=O) plays an important role in CO oxidation. When the temperature was below 210 °C, Mn=O consumption on Pt/β-MnO2 was less than β-MnO2 due to Pt4+ inhibition on CO oxidation. When the temperature was above 210 °C, Pt4+ was reduced to Pt2+, and Mn=O consumption due to CO oxidation was greater than β-MnO2. The interaction of Pt and β-MnO2 is proposed.
Keywords: CO oxidation; MnO2; Pt; bridge-type oxygen; metal–support interaction; terminal-type oxygen.