A sensor capable of monitoring hydrogen sulfide in a hydrogen-containing background. The sensor comprises novel sulfur sensitive materials that may be deposited as a thin film or thick film in a chemi-resistor format. The novel sulfur sensitive materials may comprise a single component oxide material or a composite of two or more oxide materials. The sensors respond reversibly to H.sub.2S in a reducing gas environment, with a corresponding change in their electrical resistance that can be used to quantify the amount of H.sub.2S present in the reducing gas.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
 This invention was made with government support under Contract No. DE-FC26-02NT41576 awarded by the United States Department of Energy. The United States Government has certain rights in this invention.