“…The first step of the reaction takes place at around 400e500 C, whereas the second reaction occurs at temperatures above 800 C. However, it has been suggested that at least 1000 C is needed for the SI process for improved sulphuric acid decomposition [28]. In the last step the polyhydriodic acid is decomposed to form hydrogen and iodine at temperatures higher than 300 C [29,30].…”