铪酸钡基质子导体的制备及其氢分离应用

Substitution of conventional fossil energy resources by clean and high efficient H2 energy resources is a pressing requirement to realize sustainable economy and society development. Extraction of H2 from gas mixture using dense mixed protonic/electronic conducting membrane is a low cost process for preparation of high pure H2. Because of low H2 permeation flux of present membrane, searching for new high temperature conductors with high conductivity and high stability and corresponding H2 permeable membrane system is of important meaning. In this proposal, based on the theoretical calculation in combination with experimental work, new type BaHfO3 based protonic conductors will be designed and prepared. The protonic conductors with high performance are obtained via multi- rare earth elements co-doping. The effect of doped muti-elements on the electrical conductivity, chemical stability and sintering property is revealed. Based on above mentioned results, the mixed protonic/electronic conductors with single phase by doping multi-valence metal or mixed protonic/electronic conductors with dual phase by adding second phase materials with high electronic conduction will be prepared and some fabrication laws will be described. Meanwhile, a special stuctured H2 permeable membrane is designed by external short circuit method based on protonic conductor membrane. Finally，a H2 permeable membrane with high perfromance will be achieved. In the process, the effect of some factors, such as material chemical composition, microstructure and ratio of protonic and electronic conduction for the membrane material on H2 permeation flux will be addressed; the mechanism and method for improving chemical stability of the materials in corrosive atmosphere will be investigated. By proposed research work, H2 flux and chemical stability of H2 permeable membrane materials will greatly be enhanced. The results will lay a theoretical and technological foundation for the membrane practical application.

用清洁、高效氢气替代传统能源已成为经济社会可持续发展的迫切需求。利用致密质子/电子混合导体膜从混合气中分离制氢，是低成本氢气生产技术。针对现有膜氢通量低的问题，寻求高电导率、高稳定性的质子导体及相应的透氢膜体系具有重要意义。本项目拟通过理论计算与实验相结合，设计和制备BaHfO3基新型质子导体，通过稀土元素共掺杂，构建高性能的质子导体，确立元素种类及含量对其电导率、稳定性和烧结性能的影响规律。进一步探索在上述质子导体中掺杂变价金属离子制备单相混合导体，或加入具有电子导电的氧化物第二相制备双陶瓷相混合导体的规律以及质子导体膜外部短路法制备透氢膜的工艺，获得高性能透氢膜体系。并在此过程中，阐明材料组成，微观结构，电子和离子导电的比例对透氢量的影响规律，揭示在腐蚀性气氛中提高上述材料化学稳定性的方法和机理。通过以上研究使混合导体膜在透氢量和稳定性上有突破性提高，为其实际应用奠定理论和技术基础。

用氢气替代传统能源已成为经济社会可持续发展的迫切需求。利用致密质子/电子混合导体膜从混合气中分离制氢，是低成本高纯氢气生产技术。项目针对现有膜氢通量低的问题开展研究，获得了透氢高、稳定性好的系列透氢膜体系。.采用高温固相法制备了铪酸盐基系列质子导体，如掺杂的SrHfO3、BaHfO3、LaHfO3等。通过In、Y、Yb、Ca、Sr、Ba等元素掺杂，非化学计量和加入Li2O和ZnO复合烧结助剂，制备出兼顾优异电导率和良好烧结性能的高温质子导体体系，有效改善了材料化学稳定性。在700 °C材料电导率最高可达到10-2 S∙cm-1，烧结助剂可使材料的烧结温度降低100-200 °C。采用变价元素掺杂获得的单相质子-电子混合导体，如通过In、Fe共掺杂，制备了BaHf0.8In0.2-xFexO3-δ单相质子-电子混合导体，利用过渡金属Fe离子价态的变化提供电子导电。在温度为900 ℃时，进料气50%H2/He下，膜的透氢量为0.25 mL∙min-1cm-2，高于文献报道的体系。通过引入SrFeO3、La0.9Sr0.1CrO3-δ、Gd0.2Sr0.8FeO3-δ、Ce0.8Y0.2O2等电子导体相到质子导体中，获得双相质子-电子混合导体。例如，SrHf0.8Yb0.2O3-δ-30%SrFeO3电导率达到1.31×10-1 S•cm-1，在温度900 ℃，进气70% H2/He时，膜的透氢量为0.65mL∙min-1∙cm-2，远高于其他它体系。通过外短路法引入电子传导到高温质子导体中制备了透氢膜。例如，对BaHf0.6Dy0.2In0.2O3-δ纯质子导体膜两个面用Pt浆等电子导电材料进行修饰，并与侧面密封Ag形成外部短路。在850°C，70%H2/He的情况下，获得膜的最大透氢量0.70 mL•min-1•cm-2，实现了材料质子传导的有效利用。.研究结果丰富了铪酸盐基质子导体固态离子学理论，建立了具有我国自主知识产权的透氢膜体系。将上述思想和方法进行延伸和扩展，本工作还成功地制成了固体电解质基气体传感器、新型固态钠离子/锂离子电池以及锌离子电池中，取得了满意结果。本项目实施过程中，发表相关期刊论文62篇，其中SCI收录55篇;培养博士研究生2名，硕士研究生6名，本科生8名;一篇博士学位论文获河北省优秀论文称号。