Previous experimental results have shown that a system with molten carbonate and solid oxide electrolyte is feasible for Direct Carbon Fuel Cell (DCFC). A study is presented to investigate cell performance with a range of solid carbon (i.e. coals, biochars, graphite) and operation mode in this hybrid electrolyte system. The results show that less crystalline coal with high fixed carbon, low sulfur, medium volatile material and moisture is best suited to this system. Using high rank of fuel such as anthracite coal, good cell performance can be obtained only by elevating temperature and with adequate pretreatment to remove impurities. Discussion of cell operation indicates that cell degradation and operation failure were due to coal agglomeration, ash buildup, and limited fuel supply in potentiostatic mode. Instead, galvanostatic operation gave stable cell performance over 60 hours. This result allows better understanding of anode reaction mechanism on the hybrid electrolyte system. Thus, long-term operation is promised when suitable solid fuel and optimized operation parameters are applied.

A protonic ceramic fuel cell (PCFC) and a solid oxide fuel cell (SOFC) using NiO/BZCY and NiO/YSZ anodes, respectively, were compared in H₂ and NH₃ fuels at 600 °C. The effect on the cell performance by adding lanthanum strontium ruthenium titanate (LSRT) into the anode were investigated. The performance of PCFCs in NH₃ was found to resemble that in H₂ and remain stable; by contrast, the SOFC was subject to a rigorous fluctuation of voltages in NH₃, followed by performance loss. Surface characterization evidenced that phase separation between nickel and electrolyte YSZ is a major reason to the deactivation of SOFCs. The structure degradation occurred due to repetitive nitridation of nickel and subsequent oxidation reaction. Despite containing nickel in the anode too, the PCFC experienced the little effect since the oxidation reaction occurs at the cathode. Furthermore, the addition of the LSRT helped stabilize the PCFC anode by facilitating decomposition of ammonia with exsolved ruthenium sites, which are characterized by temperature programmed reaction studies.

We investigated the performance of nickel/samarium-doped ceria (Ni/SDC) nanocatalysts on the catalytic partial oxidation of methane (CPOM). Studies of temperature-programmed surface reaction and reduction reveal that catalytic activity is determined by a synergistic effect produced by Ni metals and metal-support interaction. Catalytic activity was more dependent on the Ni content below 600 °C, while there is not much difference for all catalysts at high temperatures. The catalyst exhibiting high activities toward syngas production (i.e., a CH₄ conversion >90% at 700 °C) requires a medium Ni-SDC interaction with an Sm/Ce ratio of about 1/9 to 2/8. This is accounted for by optimum oxygen vacancies and adequate ion diffusivity in the SDCs which, as reported, also display the highest ion conductivity for fuel cell applications.