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A facile two-step method is developed to synthesize three dimensional (3D) hierarchical CaCo 2 O 4 architectures as high-performance electrode materials for lithium ion batteries (LIBs) and oxygen evolution reaction (OER). Our strategy involves a simple poly(vinylpyrolidone) (PVP)-assisted hydrothermal route and subsequent thermal treatment to produce flowerlike CaCo 2 O 4 nanostructures with a size of ∼500 nm, which is constructed by some neighboring vertical nanoplates. Whereas, the absence of PVP results in the formation of CaCo 2 O 4 microspheres, further indicating the vital role of PVP in favor of the oriented crystal growth of Co-based oxides. Benefited from the unique structural features, the resultant CaCo 2 O 4 nanoflower presents excellent cycling stability (∼560 mAh g−1 after 100 cycles at 50 mA g−1) and remarkable rate capability. Apart from superior lithium storage properties, more strikingly, CaCo 2 O 4 nanoflower demonstrates a promising candidate as a noble metal-free electrocatalyst for oxygen evolution reaction, which will spur us to find more novel functional nanomaterials for wide applications. • 3D hierarchical CaCo 2 O 4 architectures have been synthesized. • CaCo 2 O 4 nanoflower presents high lithium-storage performance. • CaCo 2 O 4 nanoflower presents high oxygen evolution reaction performance. [ABSTRACT FROM AUTHOR]

Sphere-like and cauliflower-like hexagonal-vaterite LuBO 3 have been successfully synthesized for the first time via a chemical conversion route using Lu(OH)CO 3 colloid spheres as sacrificial precursor and H 3 BO 3 as boron source without any additional surfactant. FTIR analysis provides an additional evidence of the formation of vaterite-type LuBO 3 in this method. It was found that, an appropriate amount ethanol in the hydrothermal process has a great effect on the products' morphology and crystallinity. Time-dependent experiments indicate that the formation of LuBO 3 crystals went through a two-stage growth process, which involves a fast nucleation of primary particles followed by a slow aggregation and crystallization of primary particles. An investigation on the photoluminescence (PL) properties of LuBO 3 :Eu 3+ phosphors with different morphologies indicates that their PL intensity are dependent on their crystallinity. The effect of Eu 3+ and Tb 3+ doping concentration on PL intensity were also investigated and the quenching concentration of LuBO 3 :Eu 3+ and LuBO 3 :Tb 3+ is 0.25 and 0.20, respectively. Moreover, for Eu 3+ /Tb 3+ doped LuBO 3 phosphors, the color tones can be tuned from green, through green–yellow and yellow, and then to red by simply adjusting the relative doping concentrations of the Tb 3+ and Eu 3+ ions. [ABSTRACT FROM AUTHOR]