Semiconducting gas sensor for chlorine based on inverse spinel nickel ferrite

Nickel ferrite, a p-type semiconducting oxide with an inverse spinel struct ure has been used as a gas sensor to selectively detect chlorine in air. Th is compound was prepared by two different routes namely, the citrate and co -precipitation method and sensor properties of the resulting compounds from both the methods were compared. X-ray diffraction was used to confirm the structure. The gas sensing characteristics were obtained by measuring the s ensitivity as a function of various controlling factors like dopant, concen tration of the dopant, operating temperature, concentration of the gas and finally the response time. The sensitivity to chlorine has been compared wi th that of other interfering gases. A probable explanation has been propose d to explain the selective sensitivity to oxidising gases like chlorine. (C ) 1999 Elsevier Science S.A. All rights reserved.