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The high ionic conductivity in lithium lanthanum titanate perovskite ceramics, Li3xLa(2/3)-xTiO3(LLTO), is well-known for the x≈ 0.11 lithium concentration. The grain conductivity is approximately 10–3S·cm–1at room temperature, which makes this compound one of the best candidates for the development of solid-state electrolytes. However, lower grain boundary conductivity (10–6to 10–4S·cm–1) blocks lithium diffusion. In order to increase the total conductivity of LLTO ceramics, single crystal fibers of lanthanum aluminate (LAO) were inserted into its green ceramic matrix. Our hypothesis is that single crystal fibers are capable of inducting LLTO abnormal grain growth, thus improving the overall electrical conductivity of the composite. The results show that LAO single crystals act like seeds, creating abnormal grain growth at the LaAlO3fiber surface. The impedance spectroscopy shows that the new composites have a substantial relative enhancement of total ionic conductivity (more than 200%) in comparison with the monolithic ceramic samples. This result shows the possibility of developing a novel composite design as a candidate for solid electrolyte applications.

This paper reports an experimental investigation on the effects of Nb addition on the phase transformation and photocatalytic properties of TiO2nanoparticles. Differential thermal analysis, Raman spectroscopy, X‐ray diffraction measurements reveal that Nb addition retarded the anatase‐to‐rutile phase transition. Photocatalysis experiments indicate an enhancement of the degradation of methylene blue and rhodamine B dyes with the addition of Nb to TiO2lattice. This behavior was attributed to the presence of Nb ions acting as active sites formers as well as the removal of organic species, since the presence of hydroxyls groups remained unchanged, as revealed by X‐ray photoelectron spectroscopy. An experimental investigation of the effect of Nb ionsand annealing treatment on the TiO2properties is performed. The Nb ions addition into TiO2lattice hinders the anatase‐to‐rutile phase transformation. This behavior on phase transition can be explained by the fact that the substitution of Ti4+ions by Nb5+creates additional positive charges due to charge compensation.

Photocatalysis This paper reports an experimental investigation on the effects of adding Nb on the thermal, structural, and photocatalytic properties of the TiO2nanoparticles. It is demonstrated that the phase transition could be controlled by Nb addition to TiO2lattice. Differential thermal analysis, X‐ray diffraction, and Ti K‐edge X‐ray absorption near edge structure measurements reveal that Nb addition contributed to retard the anatase‐to‐rutile phase transition, while micro‐Raman spectroscopy analysis points out that anatase and rutile phases were distributed non‐homogeneously on the samples. Photocatalysis experiments indicate that Nb addition leads to a significantly improve in the degradation of methylene blue and rhodamine B under ultraviolet irradiation being mainly influenced by order‐disorder. More details can be found in article number 1800321by Luís F. da Silva and co‐workers.