Multitechnique characterization of rhodium single atoms on rutile TiO₂(110)

Abstract

Single-atom catalysis (SAC) has emerged as a prominent research topic in the last decade. The goal is to minimize the noble metal content on metal oxide surfaces by utilizing isolated atoms as active sites. A persistent challenge in the field is the characterization of these single atoms on the surface and showing that they are the dominant sites. Generally, there are few suitable analytical techniques for this on powder catalysts.

We will show a comprehensive surface science approach to the problem. Using isolated rhodium carbonyls on titania as an example, we characterize these single sites using x-ray photoelectron spectroscopy (XPS), temperature-programmed desorption (TPD), and a newly designed infrared reflection absorption spectroscopy (IRAS) apparatus to get the bigger picture. We compare the results to studies on powder catalysts in the literature and show that multitechnique approaches are imperative for characterizing single-atom catalysts.