Abstract
This paper describes the fabrication of Ni0.6Zn0.4-Gd0.2Ce0.8O2-δ (NiZn-GDC) via a two-step wet chemical synthesis technique. This composite was found to be more thermally stable and carbon resistive under the intense reducing environment of biogas. This was confirmed by different characterization techniques. The maximum power density Pmax, was achieved at 600 °C as 820 mW/cm2 and 548 mW/cm2 with hydrogen and biogas, respectively. Different characterization techniques have been performed, such as X-ray diffractometry (XRD), scanning electron microscopy (SEM/EDX), UV–visible spectroscopy, and Raman spectroscopy. The XRD pattern by Rietveld refinement showed two-phase structures of the anode composite with an average crystallite size of 25−35nm before and after reduction with methane. The optical band gap (Egopt) of NiZn-GDC was calculated to be 2.24eV from the Tauc plot using absorbance data. The Nyquist plot was also drawn to study the AC electrochemical impedance spectra (EIS) of the nanocomposite anode from 450 °C to 600 °C in air. The maximum DC conductivity of 1.37 S/cm was observed at a temperature of 600 °C using the four-probe DC technique.
•An efficient carbon resistant composite Ni0.6Zn0.4O2-δ-GDC electrode.•The highest performance with biogas 548 mW/cm2 at 600 °C.•The addition of Zn restrains enhances the reaction kinetics with smooth gas diffusion.•The small intersections of ohmic resistance with the abscissa was 0.43 Ωcm2 at 600 °C.