Evidence of the Encapsulation Model for Strong Metal–Support Interaction under Oxidized Conditions: A Case Study on TiOx/Pt(111) for CO Oxidation by in Situ Wide Spectral Range Infrared Reflection Adsorption Spectroscopy

Abstract

Strong metal–support interaction (SMSI) has been found to significantly modify catalytic performance in the last 4 decades. The origins of the promotion effects of SMSI still reamin unclear. In this work, fully covered TiOx/Pt(111) model surfaces were prepared to mimic the proposed encapsulation model. The catalytic activities for CO oxidation on such model surfaces as a function of the TiOx coverage were examined in a model catalysis reaction cell. The TiOx ordered thin films significantly enhanced the reaction rate for CO oxidation on Pt(111). The apparent activation energy was obtained to be 51 kJ/mol for CO oxidation on the TiOx/Pt(111), which is much lower than that of 97 kJ/mol on a clean Pt(111) surface. The stability and catalytic efficiency of such SMSI model surfaces under reaction conditions were confirmed by our home-built in situ wide spectral range infrared reflection adsorption spectroscope, which is capable of measuring both the surface species and the changes of a catalyst in one spectrum...