Fischer-Tropsch Research Articles

The catalytic activity of bimetallic FeCoBEA zeolite catalysts in Fischer-Tropsch synthesis – The role of cobalt in framework position of dealuminated SiBEA zeolite

The catalytic activity of bimetallic FeCoBEA zeolite catalysts in Fischer-Tropsch synthesis – The role of cobalt in framework position of dealuminated SiBEA zeolite

Sustainable bio-jet fuel synthesis techniques for the aviation industry

Abstract In the near future, the aviation industry is expected to significantly increase the usage of “drop-in” bio-jet fuel as the technologies in biofuel production advances and matures. Given the high rate of growth in the aviation sector, the demand for aerial transportation of passenger and cargo is projected to increase by two-fold in the next twenty years. This will raise the global aviation fuel consumption to an estimated 22.48 quadrillion British thermal unit (BTU) by 2040. To meet these high energy demands, it is necessary to develop alternative and sustainable methods to produce jet fuel. In light of this, intense research and numerous fundings have been allocated into developing efficient production methods for bio-jet fuel. Conventional jet fuel emits a considerable amount of greenhouse gases (GHGs) when combusted, which contributes to global warming. Compared to traditional jet fuel, bio-jet fuel is a renewable energy source and regarded to emit less GHGs. Bio-jet fuel can be produced using a diverse range of both edible (food crops such as soybean, corn, and sugar cane) and inedible (such as energy crops, agricultural wastes, and lignocellulosic biomass) feedstocks. There are various promising technologies that can produce aviation biofuel, which includes oil-to-jet [hydroprocessed ester and fatty acids (HEFA)], alcohol-to-jet, sugar-to-jet [hydroprocessing of fermented sugars (HFS)], and syngas-to-jet [Fisher-Tropsch (FT)]. Compared to the other techniques, HEFA bio-jet fuel can be sold at a lower price because HEFA requires less capital investment, capital cost, and energy cost. Although FT technique require high capital investment, FT bio-jet fuel can be sold at medium price due to its matured technology. The breakeven cost of ATJ and HFS bio-jet fuel varies greatly due to the supply and cost of sugar-rich feedstocks, as well as short lifespan of enzymes. Although bio-jet fuel has the potential to replace petroleum jet fuel in the future, there are still many technological and socio-economic challenges that must be overcome. Therefore, this paper aims to highlight the current status, technological advances, and economic challenges of bio-jet fuel production for energy transition in the aviation industry.

Fischer-Tropsch synthesis: Platinum promoted Co@HCS catalysts

Hollow carbon sphere (HCS) nanoreactors were used as a catalyst support for Co, with Pt as a promoter. The hollow morphology of the HCSs nanoreactor was exploited to study the influence of the Pt promoter nanoparticle location relative to that of the Co3O4 (Co 10 wt%) nanoparticles (dCo = 3.5 – 12.5). Furthermore, the effect of Pt on the reduction behaviour and activity of the Co FTS catalyst was evaluated. The synthesis and use of Pt nanoparticles supported on/in Co@HCS FT catalysts to give CoPt@HCS and Pt/(Co@HCS) catalysts are reported. Electron microscopy, ex situ PXRD, BET, and TPR studies revealed that the prepared catalysts were successfully synthesized with well dispersed Co nanoparticles. It was observed that the proximity between the Co and Pt influenced the Co hcp/fcc ratios. A secondary hydrogen spillover effect was invoked to account for the reduction of Co3O4 on 1Pt/(10Co@HCS) at 335 °C. The complete reduction of Co3O4 to Co metal on 10Co1Pt@HCS at 350 °C was attributed to a primary hydrogen spillover effect. Following catalyst activation at 350 °C, the primary spillover process resulted in a catalyst exhibiting higher Fischer–Tropsch activity (approximately 2×) compared to both the unpromoted catalyst and catalysts where Pt and Co were separated by the HCS. This enhanced activity was partially attributed to the Co phases formed on the carbon support during reduction and the degree of catalyst reduction, which depended on the type of hydrogen spillover process. A comparison of the reduction ability of Os, Ru and Pt on the reduction of Co supported on/in HCSs and the impact of the promoter on Co hcp/fcc ratios is reported.

Tuning the Size of TiO2-Supported Co Nanoparticle Fischer-Tropsch Catalysts Using Mn Additions.

Modifying traditional Co/TiO2-based Fischer-Tropsch (FT) catalysts with Mn promoters induces a selectivity shift from long-chain paraffins toward commercially desirable alcohols and olefins. In this work, we use in situ gas cell scanning transmission electron microscopy (STEM) with energy-dispersive X-ray spectroscopy (EDS) elemental mapping, and near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) to demonstrate how the elemental dispersion and chemical structure of the as-calcined materials evolve during the H2 activation heat treatment required for industrial CoMn/TiO2 FT catalysts. We find that Mn additions reduce both the mean Co particle diameter and the size distribution but that the Mn remains dispersed on the support after the activation step. Density functional theory calculations show that the slower surface diffusion of Mn is likely due to the lower number of energetically accessible sites for the Mn on the titania support and that favorable Co-Mn interactions likely cause greater dispersion and slower sintering of Co in the Mn-promoted catalyst. These mechanistic insights into how the introduction of Mn tunes the Co nanoparticle size can be applied to inform the design of future-supported nanoparticle catalysts for FT and other heterogeneous catalytic processes.

PRODUCTION OF SYNTHETIC HYDROCARBONS USING COBALT CATALYSTS BASED ON ZSM-5 ZEOLITE

In this work, cobalt catalysts based on zeolite ZSM˗5 were prepared by the triple impregnation method and chemically analyzed. Zirconium dioxide was used as a promoter (3 wt. %). Chemical analysis of the elemental composition and structure of the obtained catalysts was carried out using scanning electron microscopy. It is shown that the elemental composition of the catalysts with satisfactory accuracy corresponds to their given composition. Experiments for catalytic tests of the prepared catalysts were carried out on a laboratory Fischer-Tropsch synthesis unit and synthetic hydrocarbons were obtained. Comparative characterization of activity of the obtained catalysts with cobalt content of 10 % and 20 % has been carried out, dependence of carbon monoxide conversion and selectivity with respect to formation of gas hydrocarbons and yield of liquid products on temperature has been studied.

Sonochemical and mechanochemical synthesis of iron-based nano-hydrotalcites promoted with Cu and K as catalysts for CO and CO2 Fischer-Tropsch synthesis

A novel class of Fe-based nano hydrotalcites as catalysts for Fischer-Tropsch (FT) synthesis, with a focus on CO2 hydrogenation have been prepared, characterized and tested. These catalysts were synthesized using two green, energy- and time-saving synthesis methods: ultrasound-assisted co-precipitation and solvent-free mechanochemical syntesis. The catalysts demonstrate very satisfactory CO and CO2 conversion capacities, in particular with good selectivities towards heavy hydrocarbons. The ultrasound-processed variant is particularly noteworthy, displaying about 10 % higher activity under specific conditions. The unique physicochemical properties of these catalysts, which were extensively characterized by XRD, TGA, (ATR) FT-IR, ICP-OES, SEM, TEM, BET, and TPR, are responsible for their remarkable potential for CO and CO2 conversion with varied product distribution. These findings highlight as these iron-based hydrotalcites can be considered as a new promising class of catalyst for CO and CO2 conversion by Fischer-Tropsch reaction.

Effect of pretreatment conditions on a benchmark iron catalyst for CO2 hydrogenation to light olefins

To improve the CO2-to-light olefin process in terms of economics, efficient catalysts are essential to maximize the yield. Our research was carried out on FeAlCuK, which is still considered as a benchmark for olefin formation via CO2 Fischer-Tropsch synthesis (FTS). Nevertheless, the effect of various activation conditions on the formation of desired active species and final activity of this catalyst has not been described in literature to date. We studied the pretreatment by varying both the reduction gas and temperature. The catalyst was pretreated with pure H2 or synthesis gas (H2/CO = 3) to identify the bulk and surface species formed in each case. We demonstrate that the FeCuAlK catalyst should be activated in a H2/CO atmosphere at 250 °C for 4 h before the test at typical FTS reaction conditions to reach maximum productivity. The reduction with H2/CO led to the formation of active Fe5C2 and Fe3O4 phases producing a high fraction of light olefins at higher CO2 conversion. The role of promoters K and Cu was also investigated. Selectivity for desired C2-C4 olefins increased by 10 % compared to catalysts which were used directly in FTS without preliminary activation. Characterization with ex and in situ powder X-ray diffraction, Raman spectroscopy, and XPS after each activation treatment as well as Mössbauer spectroscopy revealed a strong impact of gas nature on the phase composition which was correlated with the performance.

Solar Energy-Driven Reverse Water Gas Shift Reaction: Photothermal Effect, Photoelectric Activation and Selectivity Regulation.

Excessive carbon dioxide (CO2) emissions are one of the main causes of the greenhouse effect. Thermal catalytic reverse water gas shift (RWGS) reaction, which is a pre reaction for Fischer-Tropsch synthesis, is considered an effective way to convert CO2 and synthesize high value-added chemicals in industry. However, traditional thermal catalysis requires a large amount of fossil fuels to drive reactions, which cannot achieve the true goal of carbon neutrality. Photothermal catalysis, as a novel conversion pathway, can achieve efficient CO2 conversion while significantly improving solar energy utilization. This review provides a detailed introduction of CO2 and H2 adsorption/activation and reaction pathways in thermal catalysis, as well as the catalytic mechanisms of thermal and chemical effects in photothermal catalytic RWGS to supply readers valuable insights on the mechanism of photothermal catalytic RWGS reaction and provide a reference for better catalyst design.

Efficient and Stable Production of Long-Chain Hydrocarbons over Hydrophobic Carbon-Encapsulated TiO2-Supported Ru Catalyst in Fischer–Tropsch Synthesis

Efficient and Stable Production of Long-Chain Hydrocarbons over Hydrophobic Carbon-Encapsulated TiO₂-Supported Ru Catalyst in Fischer–Tropsch Synthesis

Comparison of Emission Properties of Sustainable Aviation Fuels and Conventional Aviation Fuels: A Review

In order to achieve the International Air Transport Association’s (IATA) goal of achieving net-zero emissions in the aviation industry by 2050, there has been a growing emphasis globally on the technological development and practical application of sustainable aviation fuels (SAFs). Discrepancies in feedstock and production processes result in differences in composition between SAFs and traditional aviation fuels, ultimately affecting the emission performance of the two types of fuel. This paper discusses the impact of CO2/NOx/SO2/CO/PM/UHC emissions from the aviation industry on the natural environment and human health by comparing the two types of fuel under the same conditions. Fuel combustion is a complex process in the combustor of an engine, which transfers chemical energy into heat energy. The completeness of combustion is related to the fuel properties, including spray, evaporation, and flammability. Therefore, engine performance is not only affected by fuel performance, but also interacts with engine structure and control laws. The CO2 emissions of SAFs differ significantly from traditional aviation fuels from a lifecycle analysis perspective, and most SAFs can reduce CO2 emissions by 41–89%. Compared with traditional aviation fuels, SAFs and blended fuels can significantly reduce SO2 and PM emissions. Pure Fischer–Tropsch hydroprocessed synthesized paraffinic kerosine (FT-SPK) can reduce SO2 and PM emissions by 92% and 70–95% respectively, owing to its extremely low sulfur and aromatic compound content. In contrast, the differences in NOx emissions between the two types of fuel are not significant, as their generation mechanisms largely stem from thermal drive and turbulent flow in the combustor, with emissions performance being correlated to power output and flame temperature profile in engine testing. CO and UHC emissions are related to engine operating conditions and the physical/chemical properties of the SAFs, with no significant upward or downward trend. Therefore, SAFs have significant advantages over conventional aviation fuels in terms of CO2, SO2, and PM emissions, and can effectively reduce the hazards of aviation to the environment and human health.

Emerging trends in hydrogen and synfuel generation: a state-of-the-art review.

The current work investigated emerging fields for generating and consuming hydrogen and synthetic Fischer-Tropsch (FT) fuels, especially from detrimental greenhouse gases, CO2 and CH4. Technologies for syngas generation ranging from partial oxidation, auto-thermal, dry, photothermal and wet or steam reforming of methane were adequately reviewed alongside biomass valorisation for hydrogen generation, water electrolysis and climate challenges due to methane flaring, production, storage, transportation, challenges and opportunities in CO2 and CH4 utilisation. Under the same conditions, dry reforming produces more coke than steam reforming. However, combining the two techniques produces syngas with a high H2/CO ratio, which is suitable for producing long-chain hydrocarbons. Although the steam methane reforming (SMR) process has been industrialised, it is well known to consume significant energy. However, coke production via catalytic methane decomposition, the prime hindrance to large-scale implementation of these techniques for hydrogen production, could be addressed by coupling CO with CO2 conversion to alter the H2/CO ratio of syngas, increasing the reaction temperatures in dry reforming, or increasing the steam content fed in steam reforming. Optimised hydrogen production and generation of green fuels from CO2 and CH4 can be achieved by implementing these strategies.

Comparative Study of Different Mesostructured Silica-supported Nano-iron Catalysts for Fischer–Tropsch Synthesis

Comparative Study of Different Mesostructured Silica-supported Nano-iron Catalysts for Fischer–Tropsch Synthesis

Engineering ZrO2–Ru interface to boost Fischer-Tropsch synthesis to olefins

Understanding the structures and reaction mechanisms of interfacial active sites in the Fisher-Tropsch synthesis reaction is highly desirable but challenging. Herein, we show that the ZrO2-Ru interface could be engineered by loading the ZrO2 promoter onto silica-supported Ru nanoparticles (ZrRu/SiO2), achieving 7.6 times higher intrinsic activity and ~45% reduction in the apparent activation energy compared with the unpromoted Ru/SiO2 catalyst. Various characterizations and theoretical calculations reveal that the highly dispersed ZrO2 promoter strongly binds the Ru nanoparticles to form the Zr-O-Ru interfacial structure, which strengthens the hydrogen spillover effect and serves as a reservoir for active H species by forming Zr-OH* species. In particular, the formation of the Zr-O-Ru interface and presence of the hydroxyl species alter the H-assisted CO dissociation route from the formyl (HCO*) pathway to the hydroxy-methylidyne (COH*) pathway, significantly lowering the energy barrier of rate-limiting CO dissociation step and greatly increasing the reactivity. This investigation deepens our understanding of the metal-promoter interaction, and provides an effective strategy to design efficient industrial Fisher-Tropsch synthesis catalysts.

Visualizing Phase Evolution of Co2C for Efficient Fischer-Tropsch to Olefins.

Cobalt carbide (Co2C) possesses high catalytic efficiency Fischer-Tropsch synthesis (FTS), while the products selectivity appears sensitive to crystallography geometry. Since the Anderson-Schulz-Flory (ASF) distribution in FTS is broken through fabricating facetted Co2C nanocrystals, yet the underlying mechanism of Co2C crystallization remains unclarified suffering from sophisticated catalyst composition involving promoter agents. Herein, the synthesis of high-purity single-crystal nanoprisms (Co2C-p) for highly efficient FTS is reported to lower olefins. Through comprehensive microstructure analysis, e.g., high-resolution TEM, in situ TEM and electron diffraction, as well as finite element simulation of gas flow field, for the first time the full roadmap of forming catalytic active cobalt carbides is disclosed, starting from reduction of Co3O4 precursor to CoO intermediate, then carburization into Co2C-s and subsequent ripening growth into Co2C-p. This gas-induced engineering of crystal phase provides a new synthesis strategy, with many new possibilities for precise design of metal-based catalyst for diverse catalytic applications.

Electrochemical Fischer-Tropsch chemistry across transition metals: A paradigm shift in sustainable liquid fuel production

This study explores electrochemical Fischer–Tropsch (EC F-T) synthesis as an eco-friendly approach for liquid fuel production, departing from conventional energy-intensive methods. While EC syngas generation is well-explored, the synthesis of F-T chemistry using CO2 and CO feed gases remains relatively unexplored. Investigating various transition metals, including Ti, Zr, V, Mo, Fe, Co, Ni, Pd, Cu, Ag, Au, Zn, and Cd, we present compelling evidence of F-T chemistry, yielding long-chain hydrocarbons (CnH2n and CnH2n+2, n=2–7), with Zn being an exception. This breakthrough involves surface C-C coupling chain growth, resembling traditional F-T synthesis, incorporating *CO and *CHx insertion reactions. Density of states and energy states near the Fermi level were analyzed. The experimental framework enhances our understanding of C-C coupling mechanisms, offering insights into environmentally friendly EC methods for long-chain hydrocarbon production and advancing innovative strategies in sustainable F-T synthesis for future energy solutions.

Response surface optimization of hydrogen-rich syngas production by methane dry reforming over bimetallic Mn-Ni/La2O3 catalyst in a fixed bed reactor

The present work utilizes a response surface optimization technique to optimize hydrogen-rich syngas production through the process of methane dry reforming (DRM). This optimization is achieved by employing a bimetallic Mn–Ni/La2O3 catalyst. The study aimed to evaluate the impact of three key parameters, namely reaction temperature, time on stream (TOS), and gas hourly space velocity (GHSV), on the hydrogen to carbon monoxide (H2/CO) ratio in syngas during the DRM. The Mn–Ni/La2O3 catalyst, synthesized using the sequential wet impregnation technique, exhibited suitable physicochemical properties necessary for DRM reaction, as evidenced by the obtained characterization data. Among the five models examined, it was found that the quadratic versus 2FI model substantially fit the experimental data, as evidenced by a p-value <0.05. The analysis of variance (ANOVA) conducted on the quadratic response surface model compared to the 2FI model demonstrated that both the reaction temperature and the TOS had a significant impact on the H2/CO ratio in the syngas. The only significant interaction factor was the relationship between the reaction temperature and the TOS. Under the specified optimal circumstances of 15 000 ml/g.h, 850 °C, and 258.15 min, an H2/CO ratio of 0.98 was achieved. The resulting H2/CO ratio of 0.98 is almost 1, indicating its suitability as a feedstock for methanol production in the Fischer-Tropsch synthesis (FTS).

LHHW/RSM reaction rate modeling for Co-Mn/SiO2 nanocatalyst in Fishcher-Tropsch synthesis

This study aims to assess the kinetics of Fischer–Tropsch (FT) reaction over the cobalt-manganese nanoparticles supported by silica oxide. Nanoparticles were synthesized by the thermal decomposition method using "[Co(NH3)4CO3]MnO4" complex and characterized by XRD, TEM, and BET techniques. The kinetics of the process were evaluated using a combination of Langmuir–Hinshelwood-Hougen-Watson (LHHW) and response surface methodology. Correlation factors of 0.9902 and 0.962 were obtained for the response surface method (RSM) and LHHW, respectively. The two methods were in good agreement, and the results showed that the rate-determining step was the reaction of the adsorbed methylene with the adsorbed hydrogen atom, and only carbon monoxide molecules were the most active species on the catalyst surface. A temperature of 502.53 K and a CO partial pressure of 2.76 bar are proposed as the optimal conditions by RSM analysis. The activation energy of CO consumption reaction was estimated to be 61.06 kJ/mol.

Frustrated Lewis pairs on Al-doped CeO2 for efficient reverse water–gas shift reaction

The reverse water–gas shift (RWGS) reaction holds promise for producing high value-added CO from CO2, serving as a crucial intermediate to feedstock for producing various hydrocarbons through Fischer-Tropsch synthesis reactions. Metallic catalysts often yield significant methane production as a by-product during operation, whereas non-metallic oxide catalysts offer potential for high CO selectivity. We prepare Al doped CeO2 nanorod by atomic layer deposition (ALD). The incorporation of Al creates more oxygen vacancies on the surface, resulting in increased Frustrated Lewis Pair (FLP) sites. Particularly, the CO yield of ALD-modified CeO2 was enhanced by 134 % compared to that of pristine CeO2 nanorods (CeO2-NR) at 500 °C, with CO selectivity reached 100 %. Density Functional Theory (DFT) calculations reveal a lower energy barrier for H2 dissociation facilitated by the formation of FLP sites, potentially leading to heightened activity in the Reverse Water Gas Shift (RWGS) reaction.

Evaluation of an alternative process for the production of hydrocarbons from CO2: Techno-economic and environmental analysis

This study aims to evaluate and compare two integrated processes (Plant A and B) for hydrocarbon production from CO2. They involve proton exchange membrane water electrolysis for H2 production, reverse water-gas shift reaction for syngas production, pressure swing adsorption for syngas purification, Fischer-Tropsch synthesis for diesel-range hydrocarbons from CO2, and atmospheric distillation for product separation. Plant B additionally integrates a hydrocracking-based upgrading section. The simulations were performed using Aspen Plus® v10, Aspen Adsorption® v10, and Aspen Custom Modeler® v10. The evaluation covers technical, economic, environmental, and multi-criteria assessment (GREENSCOPE). The proposed processes demonstrate the potential to convert CO2 to hydrocarbons, with carbon conversion rates of 75% and 71% for Plants A and B, respectively. Process energy intensity is 155 and 170 MJ/kgLP for Plants A and B, respectively. Environmental assessment reveals CO2 reduction, resulting in negative global warming potentials of −2.20 and −0.84 kgCO2-eq/kgLP for Plants A and B, respectively. The sustainability degree indices for Plants A and B are 1.00 and 0.06, respectively, indicating Plant A as the more sustainable process alternative based on both quantitative and qualitative metrics. Economic analysis shows project unviability in the Brazilian context due to reliance on H2 production and prevailing pricing conditions. Economic viability requires a price increase of liquid products by 266% and 302% or CO2-eq abatement costs ranging from 2.05 to 3.43 US$/kgCO2-eq for Plants A and B, respectively. GREENSCOPE methodology indicates better performance for Plant A across all scores, highlighting a clear connection between the hydrocracking unit and performance indicators. The findings show that these processes align with sustainable development goals (SDGs) targets for climate action (SDG 13), clean energy (SDG 7), industry, innovation, and infrastructure (SDG 9), decent work and economic growth (SDG 8), and responsible consumption and production (SDG 12). Overall, the research moves forward SDGs by offering solutions to cut carbon emissions and promote sustainable industrial practices.

In-Situ Characterization Techniques for Mechanism Studies of CO2 Hydrogenation.

The paramount concerns of global warming, fossil fuel depletion, and energy crises have prompted the need of hydrocarbons productions via CO2 conversion. In order to achieve global carbon neutrality, much attention needs to be diverted towards CO2 management. Catalytic hydrogenation of CO2 is an exciting opportunity to curb the increasing CO2 and produce value-added products. However, the comprehensive understanding of CO2 hydrogenation is still a matter of discussion due to its complex reaction mechanism and involvement of various species. This review comprehensively discusses three processes: reverse water gas shift (RWGS) reaction, modified Fischer Tropsch synthesis (MFTS), and methanol-mediated route (MeOH) for CO2 hydrogenation to hydrocarbons. Along with analysing the reaction pathways, it is also very important to understand the real-time evolvement of catalytic process and reaction intermediates by employing in-situ characterization techniques under actual reaction conditions. Subsequently, in second part of this review, we provided a systematic analysis of advancements in in-situ techniques aimed to monitor the evolution of catalysts during CO2 reduction process. The section also highlights the key components of in-situ cells, their working principles, and applications in identifying reaction mechanisms for CO2 hydrogenation. Finally, by reviewing respective achievements in the field, we identify key gaps and present some future directions for CO2 hydrogenation and in-situ studies.