Effects of metal doping on the catalytic performance of LaFe-based perovskites for CO₂ hydrogenation to light olefins

The catalytic behavior of K/LaFeBO₃ (B =Cu, Zr, Al, Mn, Ni, and Zn) perovskite catalysts prepared by sol-gel and impregnation methods was investigated for CO₂ hydrogenation to light olefins. The structure of various catalysts was characterized in detail by SEM, XRD, N₂ adsorption-desorption, H₂-TPR, CO₂-TPD, TG, and XPS analysis. With the addition of Cu and Zn, the particles size decreased with high dispersion of Fe, while the exposed basic sites increased with lower hydrogen desorption temperature. The oxygen mobility in perovskites exhibited a considerable impact on catalytic activity and olefins selectivity, which considerably increased when Fe was substituted by Cu and Zn at the B site. Olefins were formed preferentially from oxygen species of the surface lattice with low binding energies (BEs). In addition, a faster diffusion rate of oxygen would lead to an enrichment of lattice oxygen species on the surface and increase the production of olefins.