IR Nanospectroscopy in Catalysis Research

The performance of catalysts depends on their nanoscale properties.However, heterogeneities in the structure and composition of catalytic materials makes it difficult to directly monitor and identify the influence of local physicochemical parameters on their global reactivity.FTIR spectroscopy have been widely employed to probe the reaction mechanism of catalytic materials, but due todiffraction limits the spatial resolution of IR measurements can optimally reach the micrometer scale. In this review we will introduce recent developments in the field of IR nanospectroscopy that enables the extraction of detailed chemical information at the nanoscale and the identification of various nanoscale properties that influence the global performances of catalysts. Specifically, we will discuss the operation mechanism of Infrared scattering Scanning Near-field Optical Microscopy (IR-SNOM) and Photo Thermal Induced Resonance spectroscopy, which is also termed Atomic Force Microscopy Infrared (AFM-IR). Recent key examples in which these techniques were utilized in order to shed light on the properties of catalysts will be discussed. In the last part of this review, we will address the technical challenges and opportunities in expanding the scope of IR nanospectroscopy measurements into operando-mode that will enable to probe reactant-to-product transformations on catalytic reactions with nm resolution under reaction conditions.