Insight into the Metal–Support Interaction of Pt and β-MnO2 in CO Oxidation

Abstract

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 <i>β</i>-MnO₂ in carbon monoxide (CO) oxidation was studied. The Pt on <i>β</i>-MnO₂ inhibited CO oxidation below 210 °C but promoted it above 210 °C. A Pt/<i>β</i>-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/<i>β</i>-MnO₂ was less than <i>β</i>-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 <i>β</i>-MnO₂. The interaction of Pt and <i>β</i>-MnO₂ is proposed.