Electrocatalytic gas sensors working principle is based on acquisition of an electric current, while voltage ramp is applied to the sensor. The current-voltage response depends in a unique way on the type and concentration of ambient gas. Apart from other features, the current-voltage response of the sensor potentially allows a couple of gases to be detected simultaneously. The project proved that such sensors can be used for detection of various toxic gases including NO2, SO2, CO2, Cl2, H2S and NH3. The studies included sensors working with non-triangular voltage excitation, sensors with auxiliary layers, sensors with symmetric or asymmetric construction and usage of new voltammetric techniques.