Fischer–Tropsch Synthesis: Effect of the Promoter’s Ionic Charge and Valence Level Energy on Activity

In this contribution, we examine the effect of promoter´s ionic charge and valence orbital energy on catalytic activity Fe-based catalysts, based in situ synchrotron X-ray powder diffraction (SXRPD), temperature-programmed-based techniques (TPR, TPD, CO-TP carburization), Fischer–Tropsch synthesis testing studies. We compared promoting effects K (a known promoter for longer-chained products) with Ba, which has a similar radius but double charge. Despite being partially “buried” crystalline BaCO3 phase, carburization Ba-promoted catalyst was more effective than that K; primarily due to its higher (2+) With Ba2+, selectivity methane lighter products were obtained K-promoted catalysts; is likely Ba´s lesser capability suppressing H adsorption surface. An explanation provided terms limited mixing between electron-filled Ba2+ 5p filled Fe 3d orbitals, are expected be important chemical promotion, as they further apart K+ 3p orbitals.