Ni-YSZ electrodes form the benchmark in Carbon Dioxide electroreduction to CO. Ni-YSZ due its popular use in Solid Oxide Fuel Cells forms the basis of various process steps. Unfortunately, this material remains active only if a certain amount of hydrogen is supplied along side CO₂ to the inlet of the reaction. Consequently, the Ni-YSZ results in CO production via reverse water gas shift (RWGS) reaction when H₂ is supplied at the inlet. The currents for the electrode originate from electrolysis of H₂O which is formed as a result of reverse water has shift. We have quantified the amount of CO produced from RWGS vs direct CO₂ electrolysis in such a system using online mass spectrometry (MS). Electrochemical impedance spectroscopy measurements where analysed using distribution of relaxation times analysis. Under low concentration of H₂ the overall impedance is dominated by H₂ mass transfer. Effects of concentration of various reactants were measured using online MS. The process of pretreatment of the electrodes and catalyst surface development during reaction were tracked using in situ Raman Spectroscopy and optical spectrocopy. Electrodes were structurally characterised using SEM, TEM, XPS and ICP-OES measurememts. Various new combination of mixed metal oxide electrodes Ni(M)-YSZ were tested and compared with the performance of pure Ni-YSZ. Ni-YSZ electrode when used under pure CO₂ results in catastrophic failure of the electrode performance. We have investigated this failure using in situ Raman and Mass spectrometry. The mechanism of CO₂ production in pure CO₂ stream was found to be drastically different from when a small amount of H₂ is used.