A novel cermet based on CuSn-CGO is synthesized and used as a coating layer in the cathode of a conventional Solid Oxide Electrolyser for the co-electrolysis of H2O and CO2. Electrochemical experiments are carried out in the temperature range 525–600 °C by feeding reagents with a stoichiometry of 2:1 with respect to the operating current density (i.e. 150 mA cm−2). Outlet gas is analysed under OCV and operating conditions. The results are discussed in comparison with the theoretical values achievable under equilibrium. A stable electrochemical behaviour is observed in the studied temperature range. Although the performance of cell is affected by activation constraints in the temperature range 525–550 °C, minimal differences are observed with regard to the reduction kinetics of H2O and CO2. The analytical treatment of gas analysis data reveals that the coated layer promotes an increase of methane produced through the simultaneous reduction of H2O and CO2.