Chinese researchers show cerium oxide helps solid oxide fuel cells but work still needed

In China, 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.