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The rational design of nanomaterials with distinct exposed facets is of great importance for improving the physicochemical properties of these materials and for the study of structure–activity relationships. This work describes the first synthesis of lanthanum titanate (La2Ti2O7, LTO) with dandelion-like nanostructures via the molten salt method. The lowest synthesis temperature of 700 °C is at least 200 °C lower than that required by other methods. The dandelion structure consists of well-crystallized LTO nanorods (NRs) with sizes of less than 100 nm in the radial direction and 300–500 nm in the axial direction, which is different from the widely accepted two-dimensional form. LaOCl microplates were formed as an intermediate substrate for LTO NR growth outwards to the basal surfaces of the LaOCl crystallites. DFT calculation results showed that the strong LiCl adsorption on the (100) surface led to distinct growth of the (100) and (020) planes, thus promoting the rod-like growth of LTO along the [010] axis. In addition, the photocatalytic performance of as-prepared LTO was evaluated by determining the degradation of rhodamine B. The results suggested that the as-prepared LTO could markedly enhance the photocatalytic activity as a result of the surface heterojunction of coexposed {100} and {002} facets in LTO NRs. Nanomaterials: photocatalysts take a cue from dandelions A catalyst that uses light irradiation to decompose organic pollutants can become more active by being fabricated into rod-like nanostructures resembling dandelion seeds. Zhong Huang from the Wuhan University of Science and Technology in China and co-workers have developed a method for synthesizing lanthanum titanate, a ceramic that excels at separating positive and negative photogenerated charges so they can be employed for catalytic reactions. The team's approach quickly prepares lanthanum titanate nanocrystals using a bath of molten lithium and potassium salts. By optimizing the molten salt concentrations, the researchers isolated tiny aggregates of nanorods that have a high number of exposed crystal facets for charge separation. Experiments showed the nanorods could degrade model pollutants such as rhodamine dyes several times faster than conventional plate-shaped lanthanum titanates. A surface heterojunction is formed in the dandelion-like LTO, resulting in significant enhancement of the photocatalytic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrothermal activity in early Cambrian REY-rich phosphorite were disclosed. • The low-temperature hydrothermal fluid was reduced and rich with fluorine. • The hydrothermal activity slightly altered the REY patterns of phosphorite. The rare earth elements and yttrium (REY) are enriched in marine sedimentary phosphorites, which are an important REY resource. The formation of marine REY-rich phosphorites is a product of sedimentary deposition, while some geochemical studies of phosphorites suggest that they also have the characteristics of hydrothermal deposition. Hydrothermal modification can have an important effect on the distribution of REY and REY minerals in phosphorites, although there is no direct mineralogical evidence for such hydrothermal activity. In this study, we used transmission electron microscopy and other microbeam techniques to investigate the hydrothermal activity during the formation of marine sedimentary phosphorites in the early Cambrian Gezhongwu Formation, Zhijin, South China. Geochemical and mineralogical evidence shows that late hydrothermal events occurred after formation of the marine sedimentary phosphorites. The observed micro-scale hydrothermal veins (e.g., barite), micro- and nano-scale hydrothermal minerals (e.g., anatase and fluorite), and hydrothermally transformed minerals (e.g., fluorapatite and zircon) provide direct mineralogical evidence of later hydrothermal activity. The hydrothermal fluid involved in the phosphorite deposition might have been a low-temperature reduced fluid, which was enriched in F, Ti. Moreover, the late hydrothermal activity changed the REY patterns of some minerals (e.g., fluorapatite and zircon) in the phosphorites, although the hydrothermal activity was not the main factor that controlled REY enrichment in the phosphorites. Our results not only provide direct evidence for hydrothermal transformation of marine sedimentary phosphorites, but also a possible explanation for the bell-shaped rare earth element patterns in apatite, suggesting that the apatite would not provide a reliable reconstruction of the paleo-ocean environmental conditions. [ABSTRACT FROM AUTHOR]