ИСТИНА

Fischer-Tropsch synthesis (FTS) is a process of hydrocarbon production from syngas over iron or cobalt catalysts. It is a core of the X-to-liquid technology, which involves transformation of natural gas, coal or biomass into valuable chemicals. Many works devoted to the application of nanocarbon (NC) supports in FTS catalysts have been published over the past decades and the enhanced activity was found over NC-supported catalysts compared to the oxide-supported ones. Along with such obvious advantages as high reducibility of the active phase, excellent heat conductivity, and high metal dispersion NC-supported catalysts have several drawbacks such as low bulk density and powder nature. Spark plasma sintering (SPS) is a powerful technique to compact NCs by the simultaneous action of pulsed direct current and high pressure. In this work we apply SPS technique for the synthesis of NC-supported Co and Fe-based FTS catalysts. As a result, carbon-encapsulated metal nanoparticles embedded into the rigid framework-like NC structure were produced. The SPS technique also allowed eliminating the activation stage due to metal particles reduction during sintering. The sintered catalysts were tested in FTS and showed high specific and intrinsic activities: metal-time-yields of 100–200 µmolCOgMe−1s−1 and TOFs of 0.1 s−1 for Co and ~1.0 s−1 for Fe-based systems. Carbon nanotubes and graphene nanoflakes were used as a support and the effect of sintering temperature on the catalyst structure was studied along with the structural changes during FTS.