Herein, we present a systematic comparison between Pd carbonyl (Pd-CO) species observed during isothermal adsorption and several prototypical catalytic reactions to identify and understand CO adsorption on Pd/CeO2 catalysts. Using a combined experimental and computation approach through Infrared spectroscopy and Density Functional Theory (DFT), we gain a deeper understanding of the influence of the reaction microenvironment of key carbonyl intermediates. We explore the presence of Pd-CO under several reactive environments, including CO2+H2, CO+H2, CH4+CO2 and CO under gas-solid-liquid media, highlighting reactions with notable Pd carbonyl formation. The differences between Palladium carbonyls and carbonate species show that carbonyl species are much more affected via a shifting of the peak position than carbonates, which remain static irrespective of the immediate chemical environment. By following the rate of CO accumulation via K-M mode DRIFTS, we observe migration from linear, 2050 cm-1, to bridge site, 1980 cm-1, as a function of time under static CO atmosphere, where Pd-CO formed catalytically, either as a reactant, a product, or an associatively formed chemical intermediate remains consistent in peak position and relative concentration. The DFT shows that the speciation of the carbonyl is intricately linked to not only the surface structure and reconfiguration of the catalyst, modeled as a Pd (111) surface, but also the reactive microenvironment which results in distinct coverage effects between CO and additional co-reactants.