Authors: C.A. Rodríguez-González, N. Domínguez-Ruiz, P.E. García-Casilla, J.F. Hernández-Paz, M. Ramos-Murillo, H. Camacho-Montes, R.C. Ambrosio-Lazaro
Affilation: Universidad Autonoma de Ciudad Juarez, Mexico
Pages: 449 - 452
Keywords: nickel ferrite, gas, detector, H2S
The objective of this work is to study the influence of silver as additive in nickel ferrite sensors to improve the hydrogen sulfide detection sensibility. Sensors made of NiFe2O4 nanoparticles with and without Silver (3 to 5 % weight) were prepared. The nickel ferrite nanoparticles (NiFe2O4) were obtained by a chemical co-precipitation method using NaOH and NH4OH as precipitation agents. The products were characterized by XRD, FE-SEM and TEM. Results showed a spinel cubic structure with an average crystallite size of 13 nm for the samples obtained with NaOH and 19 nm for the samples obtained with NH4OH. Mixtures of NiFe2O4 nanoparticles, silver and binding agents were placed on alumina substrates to produce the sensors. Calibrations gases containing 10, 100 and 200 ppm of H2S/ balance N2 were used. The electrical resistance of the sensor was measured at different temperatures and atmosphere conditions and the sensors response were calculated. Results are promissory; they showed up to 32% improvement in the sensor sensitivity when 5% Ag was added compared to the sensor without silver addition. Moreover, the NiFe2O4+ 5% Ag sensor showed, at certain conditions, more sensitivity that other sensors doped with more expensive noble metals.