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High-temperature Fischer−Tropsch synthesis represents a sustainable alternative for direct light olefin synthesis from syngas derived from fossil and renewable feedstocks. It is found that the promotion of iron catalysts with metals used for soldering (Bi and Pb) results in a remarkable increase in the light olefin production rate with a possibility to conduct Fischer−Tropsch synthesis at low reaction pressure. A combination of characterization techniques uncovered notable migration of the promoting elements during the reaction and decoration of iron carbide nanoparticles with the promoters. The promoters seem to facilitate CO dissociation by removing O atoms from iron carbide.

A new strategy for the synthesis of metal–zeolite nanocomposite materials containing metal nanoparticles only in the zeolite pores is proposed.

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A way to improve hydrotreatment processes is to enhance the intrinsic activity of Ni or Co promoted MoS2 catalysts that are commonly used in such reactions. The aim of this work was to investigate the impact of the presence of Pluronic® P123 as a structuring agent during the synthesis of Ni promoted MoS2 catalysts (named NiMoS) in water at room temperature. A series of analyses, i.e., X-ray diffraction (XRD), chemical analysis, inductively coupled plasma mass spectrometry (ICP-MS), nitrogen adsorption-desorption isotherms, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), helped in characterizing the NiMoS-P123 and NiMoS catalysts, the latter being prepared in the absence of polymer. Both compounds contained MoS2 phase (~85 atomic% considering Mo atoms), a similar amount of mixed Ni-Mo-S phase (40–50% considering Ni) and some amount of NiS and Ni-oxidized impurity phases. The main differences between the two catalysts were a much larger specific surface area (126 m2·g−1 instead of 31 m²·g−1) and a better dispersion of the active phase as shown by the lower slab stacking (2.7 instead of 4.8) for NiMoS-P123, and the presence of C in NiMoS-P123 (9.4 wt.% instead of 0.6 wt.%), indicating an incomplete decomposition of the polymer during thermal treatment. Thanks to its larger specific surface area and lower slab stacking and therefore modification of active Mo site properties, the compound prepared in the presence of Pluronic® P123 exhibits a strong increase of the catalytic activity expressed per Mo atom for the transformation of 3-methylthiophene. Such improvement in catalytic activity was not observed for the transformation of benzothiophene likely due to poisonous residual carbon which results from the presence of Pluronic® P123 during the synthesis.

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The efficiency of niobium oxide as catalytic support of hydrodesulfurization (HDS) catalysts (CoMo and NiW) has been investigated in the HDS of a model molecule representative of sulfur compounds present in FCC gasoline (3-methylthiophene: 3MT). The NiW catalyst presented higher catalytic activity than CoMo calcined and non-calcined catalyst, however a better ratio pentane/pentene has been achieved by CoMo catalysts, which implies a lower formation of hydrogenated products. Indeed, the activity order for the catalysts evaluated is: NiW/Nb2O5 > CoMo/Nb2O5 calcined support > CoMo/Nb2O5 non-calcined support, despite the ratio pentane/pentene which has the inverse order. Furthermore, textural and chemical characterization techniques have been performed. From NH3-TPD analysis it was observed an acidity profile with a predominance of weak/strong and weak/moderate acid for CoMo and NiW catalysts, respectively. Meanwhile, the BET analysis has shown a low specific surface area for the catalysts supported by niobium oxide. Concerning the structure characteristic, the XRD analysis has suggested an amorphous phase in all catalysts analyzed.