For this work, we investigated the promotor effect (M = Na⁺, K⁺, Ce³⁺, Zn²⁺, Mn²⁺) on carbon nanosphere-encapsulated bimetallic Fe-Co core–shell catalysts for CO₂ hydrogenation, promising selectivity for converting CO₂ to light olefins. The fresh and spent catalysts were characterized using a combination of experimental techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis and differential scanning calorimetry (TGA–DSC), and Raman spectroscopy, and our results reveal that the addition of the promotor M enhanced the formation of graphitic carbon and metal carbides in the promoted catalysts when compared with the unpromoted catalysts. The metal carbides were determined to be the active sites for the production of light olefins.