Role of Ti3+ in CS2 conversion over TiO2 Claus catalyst
Abstract The objective of the study reported here was to unravel the reaction mechanism of TiO 2 catalysts used for CS 2 conversion in Claus process gas mixtures. Previously, it was demonstrated that the activity of titania exceeds that of alumina when used in the presence of H 2 S/SO 2 mixtures. In this study, it has been demonstrated that the presence and formation of Ti 3+ cation substantially improves CS 2 conversion activity for hydrolysis of CS 2 and for the Claus reaction process. This improvement is explained by a dual-centre adsorption model for CS 2 over titania which consists of chemisorption at adjacent Ti 3+ –Ti 4+ O groups. Understanding the role of Ti 3+ has allowed development of a more active Claus catalyst by introducing a pseudo “permanent Ti 3+ ” cation, Sc 3+ , into the framework structure of titania. Commercial implications based on above observation are also suggested for both catalyst designers and plant operation.