Redox Catalyst Activity Study of Lanthanum Cerate Nickel Oxide in Methane Atmosphere for Fuel Cells

Abstract

Solid oxide fuel cell (SOFCs) is promising candidate for clean and high efficient power generation system due to their high power conversion efficiency from chemical to electrical energy and its fuel flexibility. In this research work, developed lanthanum cerium nickel (La1-xCexNiO (LCN)) where x=0.2, 0.4, and 0.6 materials by sol-gel technique with improving properties including chemical stability, durability, compatibility of thermal coefficient as well as enhancing its conduction mechanism which direct effect it’s conductivity and electrochemical performance. The synthesis materials are analyzed with various techniques including, Raman Spectroscopy used for structural analysis as well as vibrational and rotational modes. UV-visible analysis used to calculate the band gap energy. Electrochemical Impedances Spectroscopy (EIS) to investigate the electric properties of materials. AC conductivity measured by EIS technique at different temperatures. The electrochemical performance examines by employing the fuel (hydrogen). Raman results show the weak peak exists in the region of 1000-1500 cm-1 and an intense peak exists in the region of 400-500 cm-1, which shows the clear presence of lattice vibrations in the prepared samples. The lanthanum hydro oxide peak at 456 cm-1 represents the Eg mode and Raman shifts reported due to doping of the materials. FTIR analysis shows the observed peaks were 650, 1059 and 1105cm-1. Vibrational peaks between 550-700cm-1 shows the presence of water contents that was solvent for sample preparations. The vibrational peaks between 550-700 cm-1 was observed due to OH bonding that is because of oxalic acid extracts that was chelating agent for gel preparations. The observed peak at 650 cm-1was because of Lanthanum hydro oxide, 1059 cm-1 for Cerium oxide and 1105 cm-1 represents the Nickel oxide. UV-visible analysis showed that the band gap values of materials decreased with the increase of the Ce2+ ions concentration. The minimum value of band gap of (La1-xCexNiO (LCN)) is 3.73 eV. EIS technique shows the value of the ohmic resistance is decreasing with increasing the temperature. The prepared material representing the ionic conductivity behavior is also showing the higher oxygen vacancies presence with increase in the temperature. The AC conductivity showed that conductivity of materials is increasing with an increase in the sintering temperature. Cathode material showed the highest conductivity 2.36 Scm-1 at 650oC. The prepared sample shows maximum OCV of about 0.949 V at temperature 650 ˚C. The LCN cathode materials have been shown good performance as they have better electrical conductivity and can be a potential candidate as a cathode material for SOFC.