Key Takeaways & Executive Findings
- •• • Co1Fe1Na1 catalyst achieved 45% total alcohol selectivity and 94.1% C2+ alcohol fraction at 260 °C and 2.0 MPa, demonstrating a viable route for higher alcohol synthesis from syngas. • • Na promoter induced Co-Fe alloy formation during reaction, while Fe enhanced Co reducibility and oxygen vacancy concentration, as confirmed by XPS and TPR, enabling dual-site synergy. • • In situ spectroscopy and post-reaction analysis confirmed coexistence of Co-Fe alloy and carbide phases (Co2C, FeCx), which balanced CO dissociation and insertion, suppressing over-hydrogenation and chain overgrowth. • • The catalyst design achieves high C2+ alcohol selectivity (94.1%) at moderate conditions (260 °C, 2 MPa), offering a promising alternative to noble-metal-based systems for industrial application.
Abstract
Direct conversion of syngas to higher alcohols (C2+ alcohols) is critical for coal-based resource utilization and energy security. Here, a series of Na-modified CoFe/Al2O3 catalysts were synthesized via incipient wetness impregnation and evaluated for syngas-to-alcohol reactions. Multiple characterizations (XRD, N2 adsorption-desorption, H2-TPR, XPS, DRIFTS, in situ Raman, Mössbauer spectroscopy) elucidated synergistic effects of Na and Fe promoters. Na facilitated formation of Co-Fe alloy sites during reaction, while Fe modified electronic state of Co and promoted transformation of lattice oxygen to adsorbed oxygen, increasing surface oxygen vacancies. Synergistic interaction between alloy and carbide sites enhanced CO insertion into olefin intermediates, improving C2+ alcohol selectivity. Under 260 °C and 2 MPa, Co1Fe1Na1 catalyst (n(Co):n(Fe):n(Na)=1:1:1) achieved total alcohol selectivity of 45%, with C2+ alcohols comprising 94.1% of total alcohols. This study provides insights into rational design of Co-based catalysts for efficient syngas conversion to C2+ alcohols.
1. Introduction
Global energy demand and environmental imperatives have intensified focus on non-petroleum routes for chemical production. China's coal-rich, oil-poor resource structure necessitates clean and efficient coal utilization. Direct syngas conversion to higher alcohols (C2+ alcohols) offers a strategic pathway to value-added chemicals and clean fuels. However, this process requires precise control over C–C coupling and C–O insertion, a challenge that has hindered commercial deployment. Conventional Co-based catalysts often suffer from poor selectivity to higher alcohols, favoring hydrocarbons or methanol.
This study addresses the bottleneck by engineering dual active sites—Co-Fe alloy and carbide—through Na promotion. The Co1Fe1Na1 catalyst achieves 45% total alcohol selectivity with 94.1% C2+ alcohols at 260 °C and 2 MPa, outperforming many reported systems. The synergistic interplay between alloy and carbide sites enhances CO insertion while suppressing over-hydrogenation, offering a rational design strategy for efficient syngas-to-alcohol conversion.
Loading authentic research manuscript (Pages 1–5)...
ZHANG Hengxuan, SUN Yan, SUN Qiwen, WU Jianmin (2026). Na Promoter Synergistic Tuning Co-Fe Alloy-Carbide Dual Sites: Directing Syngas Conversion to C2+ Alcohols. Journal of Fuel Chemistry and Technology. https://doi.org/10.1016/S1872-5813(26)60670-6
Research & Educational Purpose Only: The translations, structured abstracts, analytical annotations, and data reports provided by SinoGreenTechare intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoGreenTech claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What is the role of Na promoter in enhancing C2+ alcohol selectivity?
Na facilitates the formation of Co-Fe alloy sites during reaction, which are essential for CO insertion. It also induces carbide phase generation (e.g., Co2C, FeCx) under syngas, creating dual sites that balance CO dissociation and non-dissociative adsorption, leading to high C2+ alcohol selectivity (94.1% of total alcohols).
How does Fe incorporation affect the catalyst structure and performance?
Fe modifies the electronic state of Co, improving reducibility and promoting transformation of lattice oxygen to adsorbed oxygen, increasing oxygen vacancies. This enhances reactivity of oxygen-containing intermediates, contributing to higher alcohol formation. The Co1Fe1Na1 catalyst with equimolar Co:Fe:Na shows optimal performance.
What are the optimal reaction conditions for the Co1Fe1Na1 catalyst?
The optimal conditions are 260 °C and 2.0 MPa, under which the catalyst achieves 45% total alcohol selectivity with 94.1% C2+ alcohols. These moderate conditions are industrially attractive for syngas conversion.
What characterization techniques were used to confirm the synergistic effects?
Multiple techniques including XRD, N2 adsorption-desorption, H2-TPR, XPS, DRIFTS, in situ Raman, and Mössbauer spectroscopy were employed. XPS confirmed electronic modification and oxygen vacancies, while in situ Raman and Mössbauer identified alloy and carbide phases, correlating structure with performance.
How does this catalyst compare to existing Co-based systems in terms of selectivity?
The Co1Fe1Na1 catalyst achieves 45% total alcohol selectivity with 94.1% C2+ alcohols, which is competitive or superior to many reported Co-based catalysts. The dual-site synergy enables high selectivity to ethanol and propanol, addressing the challenge of balancing C–C coupling and CO insertion.
Related Chinese Research & Cross-Citations
Recent Advances in Carbon-Based Materials for CO2 Capture and Utilization
CO2 capture and utilization (CCU) technologies are critical for mitigating global warming and promoting resource circularity. Carbon-based materials, with tunable pore structures, abundant active sites, high specific surface area, and excellent chemical stability, show significant potential for CO2 capture and conversion. This review systematically analyzes the adsorption behaviors and performance variations of activated carbon, porous carbon, graphene, and carbon nanotubes in CO2 capture. For utilization, recent advances in catalytic applications for methanation, reverse water-gas shift (RWGS), dry reforming of methane (DRM), and alcohol synthesis are emphasized. The benefits and drawbacks of carbon materials regarding adsorption capacity, catalytic activity, and stability are evaluated, and their potential in integrated CCU technologies is discussed. Key strategies for enhancing performance through structural modulation and surface modification are elucidated. This review provides theoretical guidance for future development and large-scale implementation of carbon-based materials in CCU.
Fabrication and Microwave Absorption Performance of FexOy/TiO2/C Composites Derived from Red Mud
Red mud, an industrial solid waste from alumina production, poses severe environmental challenges. This study presents a resource-efficient strategy to convert red mud into high-performance microwave absorbing materials. FexOy/TiO2/C composites were synthesized via a sol-gel method using starch as carbon source, followed by carbothermal reduction. The phase composition and microstructure were optimized by adjusting calcination temperature and raw material ratio. The optimal sample, RmCT-5.4-700, exhibited a minimum reflection loss (RLmin) of -30.2 dB at 14.0 GHz with an effective absorption bandwidth (EAB) of 5.3 GHz at a coating thickness of 2.0 mm. The superior absorption performance is attributed to the synergistic effects of dielectric components (TiO2, graphitized carbon) and magnetic components (Fe3O4/Fe). Carbothermal reduction introduces defects that induce dipole polarization, while the conductive network formed by graphitized carbon and Fe3O4/Fe particles enhances conductive loss. Heterogeneous interfaces between Fe3O4, Fe, TiO2, and the red mud matrix promote interfacial polarization. The magnetic loss of Fe3O4/Fe improves impedance matching, facilitating electromagnetic wave penetration and absorption. This work not only provides a novel route for red mud valorization but also contributes to the high-value utilization of solid wastes.
Damage Mechanism of High Chromia Refractory in the Slag Tapping Hole of Commercial Entrained-Flow Gasifiers
The service life of refractory bricks in the slag tapping hole of entrained-flow gasifiers is a critical bottleneck for long-term stable operation. This study investigated the damage mechanism of high chromia refractories in four commercial coal-water slurry gasifiers by analyzing gasification coal samples and corroded refractory bricks. Slag characteristics, including crystallization and viscosity-temperature behavior, were evaluated. Results revealed that low-viscosity slag induces more severe refractory damage. To mitigate slag crystallization risk, a safe slag tapping temperature range is recommended as tICT−t2.5 when tICT exceeds t25. Interior morphology of corroded bricks exhibited cracks, primarily attributed to molten slag penetration and subsequent reactions with refractory material. SEM-EDS analysis of slag-aggregate and slag-matrix interfaces identified reduction in Cr2O3 content as the earliest damage characteristic. XRD detected no zirconium-containing spinel in cracks, indicating that thermal expansion mismatch between newly formed phases and the refractory matrix drives crack propagation. A damage mechanism is proposed: initial Cr2O3 depletion compromises both matrix and aggregate, facilitating slag ingress and new phase formation, ultimately leading to structural failure. Early detection or prevention of Cr2O3 reduction is essential to prolong refractory service life.
Research advances in the pyrolysis recycling of waste wind turbine blades
The global energy landscape is undergoing a profound transformation, with wind energy gaining increasing prominence due to its clean and renewable nature. However, as installed wind power capacity expands, disposal of waste wind turbine blades (WWTB) has emerged as a significant challenge. These blades are predominantly composed of epoxy resin (EP) polymers, carbon fibers (CFs), and glass fibers (GFs). Improper disposal exacerbates environmental concerns and leads to loss of valuable resources, particularly carbon-based materials. Pyrolysis technology, a versatile and environmentally sustainable method for resource recovery, has garnered considerable attention for WWTB disposal. This work presents a comprehensive review of pyrolytic recycling of WWTB, focusing on principles and classifications of pyrolysis technology, key factors influencing the pyrolysis process, as well as pyrolysis methods, equipment, products, and their applications. Through in-depth analysis of current research, this review identifies critical unresolved issues and provides a forward-looking perspective on emerging research trends. The review highlights that pyrolysis can effectively recover glass fibers and carbon fibers with mechanical property retention depending on process conditions, and that catalytic pyrolysis can enhance the quality of recovered products. Economic analysis indicates that collaborative disposal methods can improve cost-effectiveness. Future research should focus on optimizing process parameters for large-scale industrial application and developing more efficient catalysts to improve product selectivity and fiber quality.
Citric Acid-Modified HUSY Zeolite Catalyzes Alkylation of Phenol with Cyclohexanol for High-Density Aviation Fuel Precursors
Lignin-derived oxygenated aromatics, particularly phenols and aromatic ethers, are promising feedstocks for synthesizing high-density, high-heat-sink aviation fuels via alkylation-hydrogenation processes. This study systematically evaluates the catalytic performance of various zeolites (Hβ, HZSM-5, MCM-41, and HUSY) in the alkylation of phenol with cyclohexanol. Characterization demonstrates that HUSY zeolite exhibits superior catalytic activity due to its favorable pore architecture and well-balanced acid site distribution, which synergistically facilitate molecular diffusion and catalytic transformations. To further enhance catalytic properties, HUSY was modified with citric acid at various concentrations and compared with NaOH and oxalic acid treatments. Results reveal that citric acid treatment preserves crystallinity while modulating acidity and pore structure. All modified zeolites enhance phenol alkylation activity. Notably, HUSY-0.5M, exhibiting the highest medium-strong acid to total acid ratio, achieves superior performance: 80.4% phenol conversion and 99.6% selectivity for alkylation products. The catalyst also shows high activity for various lignin-derived compounds (p-cresol, anisole, guaiacol), demonstrating broad applicability. This work provides a new strategy for valorizing lignin-derived phenols into high-value fuel precursors through alkylation.
Hydrogen Production and Structure Evolution Mechanism during Thermochemical Conversion of Microalgae Pellet in Molten Hydroxide Salts
This study investigates the thermochemical conversion behavior of microalgae pellets in a molten hydroxide salt (80% NaOH-20% Na2CO3) system and its influence on hydrogen production. By comparing temperature evolution, gas release characteristics, and structural evolution of pellets with and without molten salt, and integrating char alkalization experiments, the regulatory mechanism of molten salt on reaction pathways and hydrogen production was systematically analyzed. Results indicate that molten salt significantly enhances internal heat transfer efficiency, achieving a central heating rate of 177 °C/s, effectively alleviating thermal hysteresis. Concurrently, molten salt promotes pore development through penetration, erosion, and catalytic effects, resulting in a porosity increase of 53.2%–104.3% after 10 s of reaction. Conversion efficiency is markedly improved, with the dominant reaction pathway shifting to char alkalization after only 70 s. Furthermore, when heating rate is increased above 600 °C, hydrogen yield from char alkalization improves more significantly, primarily attributed to the synergistic promotion of molten salt catalysis and rapid heating on volatiles reforming. This study provides a theoretical foundation for understanding efficient hydrogen production from biomass in molten hydroxide salts.