Infrared reflection absorption spectroscopy (IRAS) is widely utilized in heterogeneous catalysis for comparing real catalysts, model catalysts, and theoretical models. However, applying IRAS to model Single-Atom Catalysts (SACs), based on metals deposited on single-crystalline metal oxide supports, presents challenges. The first part of the presentation will discuss the development of a new IRAS setup [1]. There, we addressed the issue of low peak heights caused by metal oxide support by adjusting the incidence angle. Additionally, the optical IR path was optimized to tackle the detection of adsorbates on sparse coverage of single adatom sites. In the second part of the presentation, I will show the use of our improved IRAS setup to explore SACs, focusing on the gem-dicarbonyl IR signature, which is typically recognized as evidence of single-atom sites [2]. Our recent findings on Rh/Fe3O4 suggest the possibility of more complex scenarios, prompting further investigation of a similar system [2]. Consequently, we investigated CO adsorption on 0.05 ML Rh on TiO2 (110), during which we observed the formation of a gem-dicarbonyl complex at 250K. This observation was further validated through non-contact atomic force microscopy (nc-AFM), with both techniques determining the same orientation of the gem-dicarbonyl relative to the support. Our results align well with the theoretical Density Functional Theory (DFT) models [3] and challenge the interpretations of CO IR signatures from Rh supported on TiO2 powder [3]. Utilizing IRAS with nc-AFM and other techniques (XPS, TPD) in this multi-technique approach enhances our ability to towards more precise and reliable adsorbate identification on SAC systems. [1] Rath D.; Mikerásek V., Wang C.; Eder M.; Schmid M.; Diebold U.; Parkinson G.S., Pavelec J. 2024, submitted [2] Wang, C.; Sombut, P.; Puntscher, L.; Jakub, Z.; Meier, M.; Pavelec, J.; Bliem, R.; Schmid, M.; Diebold, U.; Franchini, C.; Parkinson, G. S., Angewandte Chemie 2024, 63 (16). [3] Tang, Y.; Asokan, C.; Xu, M.; Graham, G. W.; Pan, X.; Christopher, P.; Li, J.; Sautet, P., Nat. Comm. 2019, 10 (1).