Hydrothermal Carbon-Coated TiO₂ as Support for Co-Based Catalyst in Fischer–Tropsch Synthesis

Abstract

A range of cobalt catalysts, prepared using TiO 2 enwrapped with a hydrothermal carbon (HTC) layer, was used as a support for the Fischer−Tropsch synthesis (FTS). The effects of the HTC coating thickness and annealing process of HTC− TiO 2 on the structure and performance of the cobalt catalysts were investigated. The HTC coating with enrichment functional groups (e.g., COOH and COH) generated a strong interaction with the Co species during catalyst preparation and finally enhanced cobalt oxide dispersion. Furthermore, the protection of the surface of TiO 2 by a HTC coating improved the reducibility of the cobalt catalysts. The Co particle size was correlated with the thickness of HTC coating and the HTC−TiO 2 support annealing process. It was found that the HTC−TiO 2 support with a coating thickness of 8 nm and without an annealing process gave catalysts with a cobalt particle size of 8.6 nm and optimal FTS performance. The corresponding Co/8C-TiO 2 catalyst exhibited an activity 2.4 times higher than that of a Co/TiO 2 catalyst and showed 85% selectivity to C 5+ products under realistic FTS reaction conditions (210 °C, 1.0 MPa). The synergic effect of the HTC coating and the TiO 2 core had benefits on the catalytic properties of the Co/C-TiO 2 catalysts; the HTC coating improved dispersion and reducibility of cobalt species, while the existence of the TiO 2 core enhanced the stability of the catalyst structure in the reaction.

Plasma Assisted Preparation of CoPt/SiO2 Fischer‐Tropsch Catalysts: A Comparison of the Precursor Pre‐Thermal Treated Temperatures

“…Similar relationships between cobalt particle size and TOF values have been reported previously. [16] Although CoSi-100D + P catalyst had slightly lower TOF value compared with other samples, it possessed much higher number of active sites (~1.5-1.9 times higher), and consequently, a remarkably higher FTS reaction rate was finally presented, as can be seen the black column in Figure 7.…”

Cobalt catalysts on carbon-based materials for Fischer-Tropsch synthesis: a review

“…This technique is efficient for the synthesis of inorganic materials with different morphologies [189]. This approach was explored for the preparation of a support for mono [190,191] or bimetallic [192] catalysts for FTS. Wang et al [191] have thus synthesized Co/NGA catalysts (NGA = 3D nitrogen-doped graphene aerogel).…”

“…In another study, hydrothermal carbon-coated TiO2 was used as a support for FTS [190]. TiO2 coated by hydrothermal carbon (HTC) layers was first prepared by hydrothermal synthesis.…”

Direct observation of the evolving metal–support interaction of individual cobalt nanoparticles at the titania and silica interface

“…Severe aggregation has previously been reported to adversely affect catalytic performance resulting in low activity and poor C 5 + selectivity and stability. [69][70][71] We note that the interfacial compounds are still present in the CoNPs (i.e. a small L I 3 feature in the Co L 3edge XAS data shown in Fig.…”