Study On TPD/R Of Ammonia Synthesis Catalysts

The use of TPD/R(Temperature programmed desorption/reduction) has been set forth and the headway of research for application of TPD/R has been summarized as well, especially the present situation of their application in Ru-based ammonia synthesis catalyst. Many studies of TPD/R have been found existing in the research of single crystals. On this basis, the research work was developed considering the Hj-TPR of active carbon and H2, N2-TPD of Ru catalysts. This dissertation mainly consists of two parts, the study of Kfe-TPR for active carbon and H^ N2-TPD for Ru catalyst.The influences of different active carbon on the activity of catalyst have been investigated systematically. The effects of different treating ways for active carbons on the activities of catalysts were tested. It was found that the specific surface area of active carbons has little influence on the catalysts, but the surface groups of active carbons have some effect on the catalysts. The groups that decomposed at high temperature benefit for the catalysts, but others have no influence. The treatment for active carbons could clear the impurities on them, and could increase the activities of catalysts. Hydrogen spill over makes the reduction temperature of the promoters decreased.The adsorption of hydrogen on Ru catalysts consists of two types: tiny adsorption and strong adsorption. The former was desorpted at 150-200℃ and the later was desorpted at higher than 500℃. These strong adsorpted hydrogen may include hydrogen spill over and these adsorption made harder for nitrogen adsorption. The desorption temperature of nitrogen on Ru catalysts was about 400℃, and it's activity was around 160KJ/mol. The promoter K has much influence on the adsorption ofhydrogen and nitrogen. It made the adsorption magnitude of hydrogen and nitrogen increased greatly.At last the summarization of the whole dissertation and prospect for the research of Ru catalysts were put forward.