Interaction of H 2S with zinc titanate in the presence of H 2 and CO

Abstract

The interactions of H 2S and mixtures of H 2S/H 2 and H 2S/CO with zinc titanate at temperatures of 943, 993, and 1073 K were studied using X-ray photoelectron spectroscopy. The initial sulfur products formed on the surface were sulfide and sulfate. Sulfate formation was due to the oxygen released from the sample in the presence of H 2S, H 2, and CO. The release of oxygen was faster in the presence of reducing gases H 2 and CO than in pure H 2S, although at higher exposures to H 2 and CO, sulfate decomposed and was removed from the surface. Sulfide formation was not temperature dependent in the temperature range 943 to 1073 K, while sulfate formation was highly temperature dependent, with the maximum being at 993 K. The sulfide formation kinetics and the saturation coverage of sulfide on ZnO were similar to those of zinc titanate at 993 K but the saturation coverage of sulfide on TiO 2 was considerably lower than that of zinc titanate. The saturation coverage of sulfide in the presence of CO on both zinc oxide at 993 K and zinc titanate at 1073 K was significantly higher as compared to that in the absence of CO. This was attributed to the formation of metallic zinc and subsequent reaction with H 2S in the presence of CO. Based on the experimental results, a mechanism for the reaction of H 2S with zinc titanate was proposed.