Fischer−Tropsch Synthesis on Anchored Co/Nb2O5/Al2O3 Catalysts: The Nature of the Surface and the Effect on Chain Growth

Vegetable Oil and Derivates Hydroprocessing Using Ni as Catalyst for the Production of Hydrocarbons

The aviation sector has become a considerable market for biofuels since they come from renewable sources and have characteristics that help to reduce pollution. Hydrocarbons production from vegetable oils and their derivates for use in diesel and aviation kerosene are a possible alternative route to reduce fossil fuels. With that in mind, this article aimed to develop nickel catalysts supported on γ-Al2O3, Nb2O5, and zeolites to submit them to the hydroprocessing of vegetable oils and derivatives in the production of hydrocarbons. With soy ester, reactions with the Ni/Al2O3 and Ni/Nb2O5 catalyst showed selectivity of 41.2 and 16.5%, respectively, at a temperature of 300°C and a reaction time of 7 h. Under the same conditions, hydroprocessing reactions for the soybean ester using Ni/Beta and Ni/HY zeolites promoted more excellent conversion (between 80 and 99%) than oxide catalysts and selectivity between 30 and 70% for Ni/Beta and Ni/HY, correspondently. Besides, zeolite catalysts showed high conversion at the higher temperature (340°C) and time (9 h), reaching 100% conversion and hydrocarbons selectivity of 76.8 and 61.9% for zeolite Beta and HY, respectively. Changing the raw material to fatty acids made it possible to notice that zeolite catalysts showed high selectivity reaching 100%. Given the excellent performance of catalysts in hydroprocessing reactions, it is possible to consider them a promising alternative route since they can reduce the production by applying transition metal as a catalyst instead of noble metals used in the industry.

In situ investigation on Co-phase evolution and its performance for Fischer–Tropsch synthesis over Nb-promoted cobalt catalysts

The influences of Nb on the Co-phase evolution, reducibility, chemisorption, and Fischer–Tropsch synthesis performance of catalysts were in situ researched.

Highly selective production of heavy hydrocarbons over cobalt–graphene–silica nanocomposite catalysts

Cobalt–graphene–silica nanocomposites catalysts were applied in FTS and showed highly selective production of heavy hydrocarbons.

Towards an atomic level understanding of niobia based catalysts and catalysis by combining the science of catalysis with surface science

The science of catalysis and surface science have developed, independently, key information for understanding catalytic processes. One might argue: is there anything fundamental to be discovered through the interplay between catalysis and surface science? Real catalysts of monometallic and bimetallic Co/Nb2O5 and Pd-Co/Nb2O5 catalysts showed interesting selectivity results on the Fischer-Tropsch synthesis (Noronha et al. 1996, Rosenir et al. 1993). The presence of a noble metal increased the C+5 selectivity and decreased the methane formation depending of the reduction temperature. Model catalyst of Co-Pd supported on niobia and alumina were prepared and characterized at the atomic level, thus forming the basis for a comparison with "real" support materials. Growth, morphology and structure of both pure metal and alloy particles were studied. It is possible to support the strong metal support interaction suggested by studies on real catalysts via the investigation of model systems for niobia in comparison to alumina support in which this effect does not occur. Formation of Co2+ penetration into the niobia lattice was suggested on the basis of powder studies and can be fully supported on the basis of model studies. It is shown for both real catalysts and model systems that oxidation state of Co plays a key role in controlling the reactivity in Fischer-Tropsch reactions systems and that the addition of Pd is a determining factor for the stability of the catalyst. It is demonstrated that the interaction with unsaturated hydrocarbons depends strongly on the state of oxidation.