High-temperature solid oxide cells (SOCs) can electrochemically convert the greenhouse-gas CO2 to CO and O2, which are valuable building blocks for chemical production and other related applications. Unfortunately, the lack of efficient and stable cathode materials hinders its practical application. In recent times, SrFe0.75Mo0.25O6-δ has been identified as one of the most promising cathode materials for CO2 reduction reaction. Doping of the perovskite like SrFeO3-δ with high-valent, redox stable acidic cations such as Ti+4, Mo+6, Nb+5, Ta+5, Mo+6 has been used to enhance stability and CO2 resistance. However, It is important to tune the concentration of dopants to achieve desirable results as such acceptor doping causes a decrease in the oxygen vacancy concentration, which are active sites for the CO2 reduction reaction. It also affects the transport properties by forming a strong Mo-O bond and thus affecting oxide ion mobility. Herein, we investigate the effect of molybdenum concentration on the catalytic activity and transport properties of SrFe1-xMoxO3-δ (x=0.05, 0.15, 0.25, 0.30). The electrical conductivity, oxygen non-stoichiometry, transport properties, and impedance spectra of Sr2Fe2-xMoxO6-δ are studied at 700–900 °C within a wide range of oxygen partial pressure (0.44-10-23 bar). Chemical diffusion coefficients and surface exchange coefficients of the materials are extracted from the data of electrical conductivity relaxation. The mobility of charge carriers is estimated using the partial conductivities and oxygen non-stoichiometry data. Electrochemical impedance analysis on symmetrical cells is analyzed to obtain area-specific resistance (ASR) and fine-tune the amount of molybdenum concentration for efficient CO2 electrolysis. Distribution Function of the Relaxation Times (DFRT) is performed to deconvolute different elementary processes and explain the reaction mechanism through which CO2 reduction takes place in SrFe1-xMoxO3-δ.