HF-Free Synthesis of Anatase TiO₂ Nanosheets with Largely Exposed and Clean {001} facets and Their Enhanced Rate Performance As Anodes of Lithium-Ion Battery

An interface between toluene and water was utilized to synthesize ca. 10 nm thick of anatase TiO₂ nanosheets (NSs) with 82% exposure of {001} facets. In this procedure, highly corrosive and toxic HF, which was generally used to prepare TiO₂ NSs with largely exposed high energy facets, was avoided. Furthermore, the surfaces of the NSs were quite clean as suggested by XPS analysis. Serving as anode materials in lithium-ion batteries, these as-prepared anatase TiO₂ NSs manifested a low initial irreversible capacity loss (12.5% at 1 <i>C</i>), an excellent capacity retention at 10 C charge–discharge rate (101.9 mA h g^–1 after 100 cycles), and enhanced rate performance at 0.5–10 <i>C</i> current rates in compared with Degussa P25 TiO₂ nanoparticles (NPs). Their excellent electrochemical performances were mainly derived from the large proportion of {001} exposed facets and a very short diffusion pathway, which allowed fast and efficient Li⁺ transportation in the electrodes

Synthesis of Rhombic Dodecahedral Fe₃O₄ Nanocrystals with Exposed High-Energy {110} Facets and Their Peroxidase-like Activity and Lithium Storage Properties

Large quantities of monodispersed single-crystal rhombic dodecahedral (RD) Fe₃O₄ nanocrystals (NCs) bounded by high-energy {110} facets were prepared by using a one-pot toluene–water two-phase interfacial reaction method. By adjusting the Fe­(acac)₃ concentration and the volume of hydrazine hydrate, their sizes could be controlled in the range from 60 to 100 nm. The formation of these RD Fe₃O₄ NCs with exposed high-energy {110} surfaces might be the result of selective stabilization of such unstable facets by the C₁₇H₃₃­COO^– based on FT-IR analysis. The magnetic measurement revealed that the saturation magnetization (<i>M</i>_s) of the RD Fe₃O₄ NCs was 85 emu/g at room temperature. When used as peroxidase mimetics, the prepared RD Fe₃O₄ NCs showed excellent peroxidase-like catalytic activity toward oxidation of the substrate 3,3′,5,5′-tetramethylbenzidine and degradation of the aniline compound methylene blue dye in the presence of H₂O₂. When tested as anode materials for lithium-ion batteries, these as-obtained RD Fe₃O₄ NCs showed a high initial discharge capacity of 1147 mA h g^–1 at the current density of 0.2 C, a good cycle performance (362 mA h g^–1 at 0.2 C after 100 cycles and 191 mA h g^–1 at 1 C up to 130 cycles), and good rate capability at high current rates of 1–4 C

Coordination Polymer Nanoglue: Robust Adhesion Based on Collective Lamellar Stacking of Nanoplates

Despite a continuously growing interest in the integration of coordination polymer (CP) colloids toward functional materials, collective properties of the CP colloids have rarely been addressed mainly due to the difficulty in assembling pure CP colloids into superstructures with impressive mechanical strength. We demonstrated that CP nanoplates could stack together spontaneously upon drying the slurry of the nanoplates. The stacked CP nanoplates could work like polymeric adhesives. Versatile articles could be glued when the CP nanoplates were sandwiched between two substrates. In addition, the CP nanoplates themselves could form well-defined bulk structures without using any additional adhesives. The anisotropic shape together with the lamellar stacking way of the CP nanoplates were found to be the key points in leading to the adhesion and cohesion effect. The reasonable adhesion strength of the CP nanoglues can allow the exploration of further applications of integrated CP colloids in the future