Abstract:

The sulfur-iodine(S-I) thermochemical water-splitting cycle is one of the high-efficient methods for hydrogen production, which can be carried out at relatively low temperatures. The Bunsen reaction is particularly important as the core step of the cycle. In order to facilitate the effective separation of Bunsen reaction products, i.e., sulfuric acid and hydroiodic acid, new methods for carrying out Bunsen reaction have been studied by many scholars. In this paper, two new Bunsen reaction routes, including Bunsen reaction in non-aqueous solvents and electrochemical Bunsen reaction were reviewed. The separation of reaction products in non-aqueous solvents was discussed.The properties, advantages and disadvantages of various non-aqueous solvents were compared. It is found that the solvents adopted at present have met the requirements for the separation of Bunsen reaction products, and can be used for the Bunsen reaction, but the recovery and reuse of the solvents are difficult. The research status of electrochemical Bunsen reaction, and the comparison between the progress of two typical research teams were also summarized in this work. Most efforts have been made on the fundamental characteristics of the reaction, further attention can be paid to the electrochemical Bunsen reaction mechanism, cell structure design and optimization, and even construction of novel S-I cycle system.

Key words: hydrogen energy, sulfur-iodine cycle, solvent, electrochemical Bunsen reactionn