The electrochemical study of NixCe1-xO2-delta electrodes using natural gas as a fuel

Solid oxide fuel cells (SOFCs) enable the direct electrochemical conversion of hydrocarbon-based fuels, such as natural gas, to electricity with high efficiency. Nevertheless, the direct utilization of natural gas in the presence of Ni-based anodes is still challenging as it causes severe deposition of carbon (coke). An excellent doping matrix is the ceria (CeO2), which can lose oxygen without altering its structure. In this study, NixCe1-xO2-delta, where x = 0.2, 0.4, 0.6 or 0.8, is prepared using a sol-gel technique. The XRD results confirm the cubic structure of the prepared samples. The SEM analysis shows the porous and inhomogeneous nature of the particles with calculated sizes from similar to 22.83 to similar to 119 nm. The FTIR verifies the presence of nitrates in all the prepared anodes. UV-Vis spectroscopy demonstrates that the bandgap and optical constants decrease with increasing Ni content up to x = 0.6. The thermodynamic parameters of Ni oxidation and carbon formation are employed to study the reforming of natural gas in a SOFC system. Among the four samples, Ni(0.6)Ce(0.4)O(2-delta)d possesses the highest electronic conductivity (similar to 5.97 S cm(-1)) at 650 degrees C and a low activation energy of similar to 0.120 eV, which indicates good catalytic activity with enhanced electrochemical performance for the SOFC. A maximum power density of similar to 386 mW cm(-2) is obtained for NDC3 at 600 degrees C, which is comparable to those of other prepared electrodes. The electrochemical impedance spectrum (EIS) of NDC3 was also analysed in a hydrogen atmosphere at 600 1C. Thus, Nidoped ceria can be considered a potential anode material for SOFCs due to its efficient and excellent catalytic properties, ease in redox-based reactions, and improved resistance against the formation of coke.