2008 Volume 87 Issue 9 Pages 713-718
By partial oxidation of glucose with ZnO in high pressure high temperature water at 300°C, glucose was converted into H2 with relatively high yield and without CH4 formation. In order to understand the reaction mechanism and the optimum condition of the process, we performed glucose partial oxidation at 200-300°C to analyse an intermediate of H2, without ZnO, which probably promotes the intermediate into H2. As a result, we detected a high yield of HCOOH. The formation of HCOOH was sensitive to reaction temperature and the yield was the highest at 200°C among the experimental conditions. It was confirmed that the role of ZnO was a promoter of HCOOH decomposition into H2 and CO2 through HCOOH conversion experiments with and without ZnO at 200-300°C. The conversion of HCOOH with ZnO was within a few minutes at 300°C. Through the study, we suggested that two-stage reaction is effective for H2 formation from glucose partial oxidation: the partial oxidation of glucose is conducted at 200°C and the conversion of HCOOH is achieved over 300°C. To confirm the idea, the two-stage reaction was performed: the partial oxidation of glucose was conducted at 200°C with ZnO followed to increase temperature up to 300°C for promotion of H2 formation. The H2 yield was less amount than expected. This was probably due that ZnO prohibited the formation of HCOOH on glucose partial oxidation at 200°C.
