Synergistic K-Fe-M catalysts for efficient CO2 hydrogenation to light olefins

Light olefins (C 2 -C 4 = ) are key building blocks of the chemical industry, serving as precursors for polymers and numerous value-added chemicals. Catalytic CO 2 hydrogenation offers a sustainable route to these products and represents a promising alternative to fossil-based processes. Herein, we report a simple and versatile method for preparing synergistic K-Fe-M heterogeneous catalysts (M = Zn, Co, Mn, or Cu) for CO 2 hydrogenation to light olefins. The effects of M incorporation into the 0.03 K-Fe formulation were systematically investigated by N 2 physisorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), hydrogen temperature-programmed reduction (H 2 -TPR), CO 2 temperature-programmed desorption (CO 2 -TPD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Among the series, the 0.03 K-Fe-0.5Co catalyst demonstrated the best performance in the CO 2 hydrogenation reaction, achieving 37.8 % CO 2 conversion, 48.0 % selectivity to light olefins, and a space–time yield (STY) of 14.6 mmol g cat − 1 h −1 while maintaining excellent stability over 100 h of operation. The outstanding performance results from improved dispersion, a high density of active surface species, favorable adsorption properties, and strong synergistic interactions due to the close proximity of Fe and Co domains.