Characterization of H2S gas sensor based on CuFe2O4 nanoparticles

Copper ferrite (CuFe2O4) nanoparticles were prepared by the sol-gel auto-combustion method and used to construct a conductometric gas sensor in this work. The as-prepared CuFe2O4 nanoparticles were annealed at 500 degrees C and 750 degrees C. X-ray diffraction measurements as well as transmission electron microscopy were used to identify the crystal structure of as-prepared and annealed nanoparticles. The results reveal growth of nanoparticle size crystal structure as well as phase transition from cubic structure to tetragonal symmetry upon annealing. Fourier Transform Infra-Red Spectroscopy (FTIR) measurements of the CuFe2O4 nanoparticles revealed the tetrahedral and octahedral absorption bands that are characteristic of the spinel ferrite. Nanoparticle powder was pressed in a form of a pellet to form the gas sensor device. The pellet was placed between a copper sheet and a stainless steel grid for the bottom and top electrodes, respectively. The results revealed that the produced CuFe2O4 nanoparticles are sensitive to both H2S and H-2, but with higher sensitivity to H2S at low temperatures. The gas sensitivity of the sensors could be investigated in terms of the large number of reactive surface sites due to the large surface area of the nanoparticles as well as the adsorption of oxygen species on the surface of nanoparticles. (C) 2016 Elsevier B.V. All rights reserved.