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In the present study, Ti0.9Zr0.1Mn1.2V0.4Cr0.4 compound was synthesized from elemental powders blend via high-energy ball milling for hydrogen storage applications. The effects of milling time and subsequent annealing on the structural evaluation and morphology of the powders were investigated via X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry. Results represented that the increase of ball milling time impressively increased the amount of the BCC and Laves phases with hexagonal structure. In addition, although lattice strain augmentation and grain size reduction prompted compound to transit to an amorphous state, annealing helped desired phases to be more stable. Results of electrochemical hydrogen storage tests demonstrated that 10 h of milling resulted in highest discharge capacity. This was attributed to the sufficient C14 Laves and BCC phases and adequate crystalline defects. Increasing milling time up to 20 h, reduced the discharge capacity due to the diminution of unit-cell volume and so growing activation energy acted as a barrier for adsorption and desorption of hydrogen. The most cyclic stability was for annealed sample, which contained stable phases because of the heat treatment process. Overall results proved that operating ball milling with optimized parameters led to effective results for production of hydrogen storage in TiMn2-based alloys. [ABSTRACT FROM AUTHOR]

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 2 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 2 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 2 conversion where the perovskite coating layer migrates into the matrix of the RPC frame., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)