Traditional fossil fuels have low combustion efficiency and serious pollution, and the development of new energy conversion technologies such as wind energy and solar energy is limited by environmental conditions. As an efficient energy conversion device that directly converts chemical energy in fuel into electricity, solid oxide fuel cells (SOFCs) have attracted much attention due to their high efficiency, low emissions and strong fuel adaptability.
Although hydrogen is an ideal fuel for SOFC, its high storage and transportation limit its large-scale application. Due to its fuel flexibility, SOFC can use a variety of fuels other than hydrogen, such as methane, natural gas, methanol and bioethanol. However, when using hydrocarbon fuels such as biomass ethanol, Ni-based anode is prone to carbon deposition, causing their catalytic activity to decrease, thereby reducing cell performance and stability. Thermodynamic conditions are adjusted by adding oxidants such as water, air or carbon dioxide to hydrocarbon fuels, which can effectively improve carbon tolerance. However, the introduction of large amounts of water or air can reduce the overall efficiency of the fuel cell and increase system complexity, so the proportion of oxidizer in the fuel stream must be precisely controlled. In addition, adding a reforming layer to the surface of Ni-based anode is another effective way to improve carbon tolerance.
Cerium oxide demonstrates excellent performance as an anode reforming layer in enhancing catalyst efficiency, yet it still faces certain limitations. Firstly, its relatively low electronic conductivity may restrict electron transfer efficiency. Secondly, while cerium oxide materials exhibit catalytic activity in hydrocarbon oxidation reactions, their catalytic performance still needs improvement compared to traditional Ni-based anode materials. Research indicates that in situ nanoparticle precipitation on the catalyst matrix forms active metal hetero interfaces, which not only significantly increases the number of catalytic sites but also enhances oxygen vacancy concentration on the electrode surface, thereby improving catalyst activity and carbon tolerance.
Professor Yihan Ling's team from China University of Mining and Technology successfully prepared Ni-Fe alloy nanoparticles and high oxygen vacancy cerium heterostructure catalyst as anode reforming layer by doping transition metals such as Ni and Fe into cerium oxide, which significantly improved the electrochemical performance and anti-carbon accumulation performance of biomass ethanol T-SOFC.
The team published their work in Journal of Advanced Ceramics on August 1, 2025.
After hydrogen reduction treatment of NFCO, a NiFe alloy modified high oxygen vacancy CeO2 catalyst (R-NFCO) was obtained. XRD and TEM confirmed the formation of NiFe/CeO2 heterostructures after reduction, with NiFe nanoparticles uniformly distributed on the CeO2 substrate. XPS analysis showed that the Ce3+ content increased from 16.5% to 22.5% after reduction and the proportion of surface adsorbed oxygen increased from 29.5% to 38.6%, with a significant increase in oxygen vacancy concentration. The Ni 2p and Fe 2p spectra confirm the formation of NiFe alloy. These structural features make R-NFCO with excellent catalytic activity.
The catalytic performance of NFCO catalyst in C2H5OH-CO2 atmosphere was evaluated using a fixed bed reactor. At 700 ℃, as the fuel concentration increases from 5% to 15%, the content of H2, CO, CH4 and CO2 in the reformed gas significantly increases, attributed to the higher concentration of fuel generating more products through reforming and decomposition reactions. It is worth noting that after hydrogen reduction treatment, the proportion of H2 and CO in the reformed gas is significantly higher than that in the unreduced sample. This is because the NiFe alloy formed during the reduction process greatly increases the number of active sites on the catalyst, thereby more effectively adsorbing and activating C2H5OH and CO2 molecules, promoting their conversion into synthesis gas and improving ethanol conversion efficiency.
The cell with R-NFCO reforming layer under 700 ℃ and 10% C2H5OH-CO2 conditions remained stable during 100 h, while the performance of the cell without reforming layer deteriorated significantly. Raman spectroscopy shows that the T-SOFC without reforming layer has a higher ID/IG ratio, indicating that its anode accumulates more amorphous carbon. The exhaust gas confirms that the cell with reforming layer can stably maintain high H2/CO production, while the conversion efficiency of the cell without reforming layer continues to decrease due to carbon deposition covering the active sites.
The introduction of NFCO reforming layer significantly improves the operational stability of T-SOFCs in ethanol atmosphere. This improvement provides a feasible path for the long-term stable operation of cells under more complex fuel conditions.
About Author
Yihan Ling is a professor and doctoral supervisor at China University of Mining and Technology, Humboldt Scholar, JSPS Foreigner Special Research Fellow, Jiangsu Provincial Outstanding Youth and core member of Jiangsu Innovation and Entrepreneurship Team.
He has published more than 150 SCI papers in Advanced Materials, Applied Catalysis B-Environment, Advanced Functional Materials, etc., and has been selected as the "top 2% of global scientists with annual influence" for a consecutive time. In the past five years, he has presided over more than 20 projects, including National Key R&D Program, International Innovation Cooperation under the National Key R&D Program, General Project of National Natural Science Foundation, Outstanding Youth Project of Jiangsu Provincial Natural Science Foundation.
His research interests mainly include: (1) solid-state batteries (solid oxide fuel cells/electrolysis cells, all-solid-state lithium, sodium ion batteries); (2) Research and development of environmental and energy functional ceramic materials and products (ceramic membrane reactors, preparation and application technology of porous ceramic membranes for water treatment, high-temperature ceramic gas separation membranes).
About Journal of Advanced Ceramics
Journal of Advanced Ceramics (JAC) is an international academic journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press, and exclusively available via SciOpen . JAC's 2024 IF is 16.6, ranking in Top 1 (1/33, Q1) among all journals in "Materials Science, Ceramics" category, and its 2024 CiteScore is 25.9 (5/130) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508
