Enhancing catalytic activity of V2O5/TiO2 in H2S selective oxidation by modulating oxygen adsorption conditions

Abstract

This paper aimed to reveal the effects of chemisorbed oxygen species on selective catalytic oxidation applied for H2S removal. A sequence of thermal treatments were conducted on V2O5/TiO2 samples to prepare catalysts that possess different distributions of oxygen species. Characterization by X-ray photoelectron spectroscopy enabled a distinction among three different chemisorbed oxygen species: O–, O22–, and O2–. In addition, the dominance of the O– species, which is a very reactive oxygen species for catalytic oxidation reactions, was observed when the catalyst was exposed to 5% O2/N2 gas at the low temperature of 30 °C. It was also found that the N400A30 with the highest ratio of O– species was superior to others at converting H2S into elemental sulfur over the whole range of temperatures: the best S yield of N400A30 was 85% at 130 °C. These results are promising, as thermal treatments for oxygen adsorption were adopted for the first time to improve the catalytic activity of H2S removal by modulating the proportion of highly reactive O– species.