The porous honey comb-like La2O3 thin films have been synthesized using one step spray pyrolysis method. The influence of sprayed solution quantity on properties of La2O3 thin films is studied using X-ray diffraction, Fourier transform spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, optical absorption and Brunauer-Emmett-Teller techniques. Morphology of La2O3 electrode is controlled with sprayed solution quantity. The supercapacitive properties of La2O3 thin film electrode are investigated using cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance techniques. The La2O3 film electrode exhibited the specific capacitance of the 166 F g(-1) with 85% stability for the 3000 cycles. The La2O3 film electrode exhibited sensitivity of 68 at 523 K for 500 ppm CO2 gas concentration. The possible CO2 sensing mechanism is discussed. (C) 2016 Elsevier Inc. All rights reserved.