Study On Perovskite Oxygen Permeation Membrane For Hydrolysis Of Hydrogen Production

The hydrogen has very important significance in the energy system, as one of strategic energy in the world. Hydrogen is a energy substance that abundant resources, high calorific value, environmental protection and renewable energy, is the ideal fuel in the future. There is various ways for hydrogen production, currently, thermochemical decomposition of water for hydrogen generation was studied widely. Thermochemical decomposition of water based on oxygen exchange material (OEM) and raw materials which are using for hydrogen production, carried out a redox reaction to achieve hydrogen production initially, also known as chemical looping hydrogen (CLH). As the development of membrane reactor, and the process is coupled to the membrane reactor, thus the continuity of hydrogen production was able to achieve. Perovskite oxides of rare earth materials is a unique physical and chemical properties of inorganic functional materials. Its structural formula can be expressed as ABO3, an ideal cubic perovskite structure has tetragonal symmetry, Perovskite of cubic structure be benefit of conduction for the oxygen ion and electron, which has been widely applied in all fields such as industrial catalysis, electrode materials and environmental protection. In consideration of the special properties of perovskite and extensive research of oxygen transport membranes (mixed ionic-electronic conducting membrane), with perovskite as oxygen exchange materials presented in this article, and processing is made for oxygen transport membranes-oxygen exchange materials (OTM-OEM). This article is mainly using the perovskite OTM unique catalytic properties as the substance, which is applied to hydrogen production water splitting.LaxCa1-xFeO3-δandBaFexZr1-xO3-δ(x=0.1、 0.3、 0.5、0.7、0.9) perovskite OEM was prepared by co-precipitation in this article, OEM were characterized by X-ray diffraction (XRD), thermogravimetric-differential scanning calorimeter (TG-DSC), and H2 temperature programmed reduction (H2-TPR) et al. The purpose is to represent phase composition, during the formation of heat and mass changes, and redox properties, Using CH4-TPR, and CO-TPR was tested activity in the reaction process. Simultaneously catalyst were prepared by impregnation method and were characterized by XRD, H2-TPR and BET technologies, and was loaded onto OTM. Its was explored for OEM formation membrane, and OTM-OEM was prepared by tableting. OTM-OEM was characterized by XRD and SEM-EDS, and building on membrane reactor was evaluated by oxygen permeability and hydrogen production performance.Through the characterization techniques discovered that was successfully prepared OEM of LaxCa1-xFe03_δ and BaFexZr1-xO3-δ, and the OEM have excellent activity and stability. Meanwhile characterization of OTM that was discovered dense structure and favorable stability before and after the reaction. OTM oxygen permeability be superior of La0.1Cao.9Fe03-δ, Lao.9Ca0.1FeO3-δ, and BaFeo.9Zr0.103-δat 900℃, and oxygen permeation flux was 3.0xl0-8mol/(s-cm2). Using oxygen permeability test was discussed oxygen transfer mechanism.In water splitting experiment process found that the decomposition of water vapor was achieved above 800℃, and hydrogen production rate increases with increasing temperature. Experiment indicated that hydrogen production rate, structure, and stabilization of Lao.9Cao.1Fe03-δ and BaFe0.9Zr0.103-δ was preferable at 900℃, and the maximum hydrogen production rate was 5.0cm3min-1cm-2. Whereafter, in membrane reactor using OTM-OEM supported catalysts was evaluated by water splitting for hydrogen production, as a result, performance of hydrogen production did not improve significantly, and were analyzed reasons that were catalyst performance and supporting modes of influence.