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Nowadays, to alleviate the growing pressure of energy shortages and environmental pollution, electrochemical energy conversion is seen as a fossil‐free, secondary pollution‐free, and highly efficiency pathway. Electrocatalysts, as the “heart” of the electrochemical conversion process, play a key role in accelerating reaction rates and promoting efficiency. Transition‐metal‐based layered double hydroxides (TM LDHs), one of the famous electrocatalysts, show unique 2D supermolecular‐stratified structure, excellent electronic properties, and their raw materials are easily available. In this review, electrocatalysis‐related properties of TM LDHs and the state‐of‐the‐art synthesis methods of TM LDH‐based electrocatalysts are summarized. Modifications for promoting the development of TM LDH‐based electrocatalysts are included, such as carbon materials modification, defect engineering, and noble metal loading. Then, the application of TM LDH nanosheets in the field of electrocatalysis is reviewed in detail. Finally, recent challenges, ongoing improvements, and future expectations for TM LDH nanosheets are presented.

The color point tuning is significant for expanding the application of optical materials (phosphors). In this work, one type of single Eu2+-activated high bright phosphor was prepared, and the color point could be tuned only by controlling the doping level of the activator ion. The phase and crystal structure of the matrix material Y2Mg2Al2Si2O12 (YMAS) were identified and analyzed. The luminescence properties including excitation and emission spectra, peak position attribution, spectral tuning, variation of luminescent intensity, and full width at half-maximum were investigated and explained. The application performance of phosphors and light-emitting diode (LED) devices were tested and discussed. All above results reveal that the YMAS:Eu2+ phosphors can be considered as feasible candidates for ultraviolet LED applications for solid state lighting and backlight display areas.

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Thermal activation of upconversion luminescence in nanocrystals opens up new opportunities in biotechnology and nanophotonics. However, it remains a daunting challenge to achieve a smart control of luminescence behavior in the thermal field with remarkable enhancement and ultrahigh sensitivity. Moreover, the physical picture involved is also debatable. Here we report a novel mechanistic design to realize an ultrasensitive thermally activated upconversion in an erbium sublattice core–shell nanostructure. By enabling a thermosensitive property into the intermediate 4I11/2 level of Er3+ through an energy-migration-mediated surface interaction, the upconverted luminescence was markedly enhanced in the thermal field together with a striking thermochromic feature under 1530 nm irradiation. Importantly, the use of non thermally coupled red and green emissions contributes to the thermal sensitivity up to 5.27% K–1, 3 times higher than that obtained by using conventional thermally coupled green emissions. We further demonstrate that the controllable surface interaction is a general approach to the thermal enhancement of upconversion for a series of lanthanide-based nanomaterials. Our findings pave a new way for the development of smart luminescent materials toward emerging applications such as noncontact nanothermometry, information security, and anticounterfeiting.

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In order to analyze and evaluate different trace metals on surface water of the Changjiang River, concentrations of dissolved trace metals (Cu, Ni, Fe, Co, Sc, Al, Zn, Pb, Cd, Se, As, Cr, and Hg), major elements (Ca and Mg), and nutrient (NO3- were measured. Samples were taken at 76 positions along Changjiang River in flood and dry seasons during 2007-2008. Spatial distributions identified two main large zones mainly influenced by mineral erosion (sites 1-22) and anthropogenic action (sites 23-76), respectively. Principal component analysis (PCA) and hierarchical cluster analysis were used to identify the variance distinguishing the origin of water. Four significant components were extracted by PCA, explaining 74.91% of total variable. Cu, Ni, Fe, Co, Sc, Al, Ca, and Mg were mainly associated with the weathering and erosion of various rocks and minerals, while an anthropogenic source was identified for Cd and As. Although erosion was one source of Pb and Zn, they were also input by atmospheric deposition and industrial pollutions. NO3- and Se were mainly associated with agriculture activities. However, Hg and Cr showed different sources. CA confirmed and completed the results obtained by PCA, classifying the data into two large groups representing different areas. Group 1 referred to the upper reaches which represented samples mainly corresponding to natural background areas. Group 2 referred to the middle and lower reaches including samples under anthropogenic influence. Meanwhile, group 2 was subdivided into three new groups, representing agricultural, industrial, and various artificial pollution sources, respectively.