Parvanian Amir Masoud, Salimijazi Hamidreza, Shabaninejad Mehdi, Troitzsch Ulrike, Kreider Peter, Lipiński Wojciech, Saadatfar Mohammad
Department of Materials Engineering, Isfahan University of Technology Isfahan 84156-83111 Iran
Department of Applied Mathematics, Research School of Physics and Engineering, The Australian National University Canberra ACT 2601 Australia
RSC Adv. 2020 Jun 17;10(39):23049-23057. doi: 10.1039/d0ra02353a. eCollection 2020 Jun 16.
In this paper, we investigate the redox performance of perovskite coated porous ceramics with various architectures. For this purpose, reticulated porous ceramics (RPCs) in three different pore sizes (5, 12, 75 ppi) were fabricated to represent a broad range of structures and pore sizes. The perovskite material is based on lanthanum manganite and was synthesized and doped with Ca and Al through the Pechini method. Using a deep coating method, the surface of RPC substrates was modified by a thin-film coating with a thickness of ∼15 μm. We evaluated the CO conversion performance of the developed materials in a gold-image IR furnace. X-ray micro-computed tomography along with SEM/EDX were utilized in different steps of the work for a thorough study of the bulk and surface features. Results reveal that the intermediate pore size of 12 ppi delivers the maximum perovskite loading with a high degree of coating homogeneity and connectivity while CO conversion tests showed the highest CO yield for 75 ppi. Our results show that the extreme conditions inside the furnace combined with the flow of gaseous phases cause the RPCs to shrink in length up to 23% resulting in the alteration of the pore phase and elimination of small pores reducing the total specific surface area. Further our results reveal an important mechanism resulting in the inhibition of CO conversion where the perovskite coating layer migrates into the matrix of the RPC frame.
在本文中，我们研究了具有不同结构的钙钛矿涂层多孔陶瓷的氧化还原性能。为此，制备了三种不同孔径（5、12、75孔每英寸）的网状多孔陶瓷（RPC），以代表广泛的结构和孔径范围。钙钛矿材料基于镧锰氧化物，通过佩琴尼法合成并掺杂了钙和铝。采用深度涂层法，用厚度约为15μm的薄膜涂层对RPC基体表面进行改性。我们在金成像红外炉中评估了所制备材料的一氧化碳转化性能。在工作的不同阶段利用X射线微计算机断层扫描以及扫描电子显微镜/能谱仪对整体和表面特征进行深入研究。结果表明，12孔每英寸的中等孔径可实现最大的钙钛矿负载量，且涂层具有高度的均匀性和连通性，而一氧化碳转化测试表明75孔每英寸的一氧化碳产率最高。我们的结果表明，炉内的极端条件与气相流动相结合，导致RPC的长度收缩高达23%，从而导致孔相改变并消除小孔，降低了总比表面积。此外，我们的结果揭示了一种导致一氧化碳转化受抑制的重要机制，即钙钛矿涂层迁移到RPC框架的基体中。
