Carbon Spheres Prepared by Hydrothermal Synthesis-A Support for Bimetallic Iron Cobalt Fischer-Tropsch Catalysts

Vapour phase hydrogenation of cinnamaldehyde using cobalt supported inside and outside hollow carbon spheres

The hydrogenation of cinnamaldehyde is usually performed in the liquid phase in batch mode. In this study, a vapour phase flow system has been used to evaluate the use of cobalt catalysts supported inside and outside hollow carbon spheres (HCSs). The influence of temperature, hydrogen flow rate, and catalyst mass on the hydrogenation reaction was investigated. The catalysts generally showed modest conversion to the required products, hydrocinnamaldehyde, 3-phenyl propanol, cinnamyl alcohol, together with formation of various decomposition products. The data revealed that the Co@HCS showed better conversion and product selectivity compared with the Co/HCS. The catalysts with smaller particle sizes (ca. 6 nm) were more efficient than those with larger particles (30–40 nm). An increase in reaction temperature (200–300 °C) resulted in a lower cinnamaldehyde conversion and a poor product selectivity. TPR studies revealed that the Co@HCSs had a stronger metal-support interaction than the Co/HCSs catalysts. Catalyst recycling studies revealed that only the Co/HCSs could be regenerated (four cycles) and post reaction analysis of the catalysts revealed that this was due to HCS pore blockage and not Co sintering.

Electronic effects of transition metal dopants on Fe(100) and Fe5C2(100) surfaces for CO activation

Spin polarized density functional theory computations were performed to elucidate electronic effects based on first-row transition metal doped Fe(100) and Fe₅C₂(100) surfaces for CO dissociation.

Novel urchin-like FeCo oxide nanostructures supported carbon spheres as a highly sensitive sensor for hydrazine sensing application

Herein, we successfully fabricated a novel nanostructure based on hierarchical urchin-like FeCo oxide supported carbon spheres (FeCo Oxide/CSs) via a two-step hydrothermal method followed by a simple annealing step at 300 °C under air. It was found that such urchin-like FeCo Oxide/CSs structure exhibited superior catalytic activity towards hydrazine oxidation to CSs, Fe Oxide/CSs, Co Oxide/CSs, and FeCo Hydroxide/CSs material. In this regard, the FeCo Oxide/CSs displayed a wide linear detection range of 0.1-516.6 μM, low detection limit of 0.1 μM, and long-term stability. The material also showed good selectivity towards hydrazine detection in the presence of various interferences, such as uric acid, ascorbic acid, urea, dopamine, Na⁺, SO₄^2-, K⁺, and Cl-. The excellent sensing performance of the FeCo Oxide/CSs was assumed to the unique hierarchical urchin structure with the high density and uniformity of nano-sized FeCo Oxide nanoneedles, which produced massive electroactive sites and enhanced charge transfer ability. The achieved results implied that the FeCo Oxide/CSs may be a great candidate for sensitive hydrazine detection.

Use of Plasma-Synthesized Nano-Catalysts for CO Hydrogenation in Low-Temperature Fischer⁻Tropsch Synthesis: Effect of Catalyst Pre-Treatment

A study was done on the effect of temperature and catalyst pre-treatment on CO hydrogenation over plasma-synthesized catalysts during the Fischer–Tropsch synthesis (FTS). Nanometric Co/C, Fe/C, and 50%Co-50%Fe/C catalysts with BET specific surface area of ~80 m² g^–1 were tested at a 2 MPa pressure and a gas hourly space velocity (GHSV) of 2000 cm³ h⁻¹ g⁻¹ of a catalyst (at STP) in hydrogen-rich FTS feed gas (H₂:CO = 2.2). After pre-treatment in both H₂ and CO, transmission electron microscopy (TEM) showed that the used catalysts shifted from a mono-modal particle-size distribution (mean ~11 nm) to a multi-modal distribution with a substantial increase in the smaller nanoparticles (~5 nm), which was statistically significant. Further characterization was conducted by scanning electron microscopy (SEM with EDX elemental mapping), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The average CO conversion at 500 K was 18% (Co/C), 17% (Fe/C), and 16% (Co-Fe/C); 46%, 37%, and 57% at 520 K; and 85%, 86% and 71% at 540 K respectively. The selectivity of Co/C for C₅₊ was ~98% with 8% gasoline, 61%, diesel and 28% wax (fractions) at 500 K; 22% gasoline, 50% diesel, and 19% wax at 520 K; and 24% gasoline, 34% diesel, and 11% wax at 540 K, besides CO₂ and CH₄ as by-products. Fe-containing catalysts manifested similar trends, with a poor conformity to the Anderson–Schulz–Flory (ASF) product distribution.

Hydrogenation of CO2 into hydrocarbons: enhanced catalytic activity over Fe-based Fischer–Tropsch catalysts

The conversion efficiency of CO₂ in CO₂-FTS over Fe-based catalysts is significantly enhanced by driving the conversion of the CO intermediate via the FTS reaction over a second kind of FT component, Co or Ru, without WGS activity.

Generation of radical species in CVD grown pristine and N-doped solid carbon spheres using H2 and Ar as carrier gases

A mechanism showing the role of carrier gas on the N-configuration of the post-N-doped CSs synthesized in the presence of (a) H₂ and (b) Ar, respectively.

Cobalt nanoparticles embedded in a porous carbon matrix as an efficient catalyst for ammonia decomposition

A metallic Co nanoparticle catalyst embedded in a carbon matrix catalyst was synthesized through a facile solvothermal method and subsequent thermal treatment.

Study on Fe–Co alloy role over RANEY® Fe–Co bimetallic catalysts in Fischer–Tropsch synthesis

Supersaturated R-Fe_0.2Co_0.8 and R-Fe_0.1Co_0.9 catalysts exhibited the best CO conversion and higher C₅₊ selectivity.

Microwave treatment: a facile method for the solid state modification of potassium-promoted iron on silica Fischer–Tropsch catalysts

Potassium-promoted (0–1.5 wt%) iron–silica catalysts for Fischer–Tropsch synthesis (FTS) have been modified using microwave radiation.