Loading and promoter effects on the performance of nitrogen functionalized graphene nanosheets supported cobalt Fischer-Tropsch synthesis catalysts

Abstract

The effects of nitrogen functional groups on graphene surface and also the effects of cobalt loading and ruthenium promoter on the performance of nitrogen functionalized graphene nanosheets (N-GNS) supported cobalt catalysts in FischereTropsch synthesis (FTS) are investigated. A 15 wt% Co/PGNS catalyst, a series of Co/N-GNS (15e30 wt% loading) and ruthenium promoted catalysts (25 wt% Co,0.5 wt% Ru/N-GNS and 25 wt% Co,0.5 wt% Ru/ PGNS) were prepared by impregnation method. The purified GNS and functionalized GNS and all catalysts were characterized by Raman spectroscopy, FTIR, SEM, EDS, ICP, BET, TEM, XRD and TPR. The catalysts assessed in FTS in a fixed bed micro-reactor at 220 C, 1.8 Mpa and H 2 /CO ratio of 2. Functionalization of GNS shifted the TPR reduction peaks to lower temperature, increased the dispersion of cobalt particles and increased the percentage CO conversion from 70.6% to 74.5%. Increasing the cobalt loading resulted in increasing the average cobalt cluster size, improvements in the reducibility of Co 3 O 4. The maximum FTS activity for N-GNS supported catalyst is achieved at 30 wt % cobalt loading. The C þ 5 selectivity for the 30 wt % cobalt catalyst was higher than that of the 15 wt % Cobalt catalyst. Addition of 0.5 wt%Ru increased the FTS rate (gCH/(gcat$h)) from 0.377 to 0.412 and the liquid products selectivity from 86.5% to 91.2%.

Synthesis, characterization and magnetic properties of Ni, Co and FeCo nanoparticles on reduced graphene oxide for removal of Cr(VI)

“…The combination of graphene and nickel nanoparticles shows enhanced performance of microwave absorbance than graphene and nickel nanoparticles individually due to the improvement of electromagnetic loss [9]. Nitrogen-functionalized graphene nanosheet offers sites for loading of cobalt nanoparticles, which act as a catalyst for Fischer-Tropsch synthesis gas to liquid conversion [10]. Ruthenium can be added to nitrogen-doped reduced graphene cobalt nanoparticles composites, which promotes the activity of cobalt for better yields [10].…”

“…Nitrogen-functionalized graphene nanosheet offers sites for loading of cobalt nanoparticles, which act as a catalyst for Fischer-Tropsch synthesis gas to liquid conversion [10]. Ruthenium can be added to nitrogen-doped reduced graphene cobalt nanoparticles composites, which promotes the activity of cobalt for better yields [10].…”

Hydroxyapatite as a new support material for cobalt-based catalysts in Fischer-Tropsch synthesis

“…strong interaction between alumina and silica with cobalt species favors high Co dispersion, however, this phenomenon leads to the formation of small Co nanoparticles and refractory species, namely, Co aluminates or Co silicates, that are hard to reduce [12,13]. On the contrary, weakly interacting supports like carbon-based materials give rise to poor dispersion, and thus a low ratio of surface Co metal sites [14]. Therefore, a trade-off must be found.…”

Ru-containing Catalysts for Liquid-phase Fischer-Tropsch Synthesis

“…Известно, что для катализаторов СФТ слабое взаимодействие между носителем и активным металлом является одним из ключевых факторов [6]. В настоящее время наноразмерные мезопористые материалы, такие как бета-цеолиты [7], активированный уголь [5], α-глинозем [8], оксид титана [9] и графеновые наночастицы [10] широко используются в СФТ. Кроме того, существует ряд работ, посвященных применению глинозема, покрытого цеолитовой пленкой ZSM [11] и металлорганических каркасов (MOF) [12] в качестве носителей для катализаторов Co и Fe.…”