In the present investigation, sensing electrode of an electrochemical CO2 gas sensor (plate type design) is engineered to overcome various observed failures such as dying out in short time due to Au/Pt diffusion into the material which discontinues the electrical contact and results into inadequate catalytic action. To improve the sensing electrode performance, a gradient sputtered Au coat is applied over it with increasing thickness towards the centre of the pellet. In another design, Au is loaded with varying concentration into the electrolyte material and its coat is applied on the electrolyte to overcome the diffusion. Performance of different sensors with varied configuration of catalyst Au is compared on the parameters namely stability and response time. The gradient sputtered electrode gave fast electrode kinetics, whereas sensor stability is found better for Au loaded material. An insight into effect of Au loading in the binary electrolyte (Li2CO3 +CaCO3) is obtained by complex impedance spectroscopy.