A novel amperometric-type NO2 sensor based on La10Si5NbO27.5 (LSNO) electrolyte and nano-structured CuO sensing electrode was fabricated and tested. A bilayer LSNO electrolyte including both a dense layer and a porous layer was prepared by conventional solid state reaction method and screen-printing technology. The nano-structured CuO sensing electrode was in situ fabricated in LSNO porous layer by impregnating method. The composition and microstructure of the sample were characterized by XRD and SEM, respectively. The results showed that the CuO particles with diameters range of 200-500 nm were homogeneously dispersed on the LSNO backbone in porous layer. The sensor exhibited well sensing characteristics to NO2. The response current was almost linear to NO2 concentration in the range of 25-500 ppm at 600-800 degrees C. With increase of operating temperature, the sensitivity increased and reached 297 nA/ppm at 800 degrees C. The response currents toward NO2 were slightly affected by coexistent O-2 (0-21 vol%) and CO2 (0-5 vol%). (C) 2013 Elsevier B.V. All rights reserved.