Solvothermal-Induced 3D Macroscopic SnO₂/Nitrogen-Doped Graphene Aerogels for High Capacity and Long-Life Lithium Storage

3D macroscopic tin oxide/nitrogen-doped graphene frameworks (SnO₂/GN) were constructed by a novel solvothermal-induced self-assembly process, using SnO₂ colloid as precursor (crystal size of 3–7 nm). Solvothermal treatment played a key role as N,N-dimethylmethanamide (DMF) acted both as reducing reagent and nitrogen source, requiring no additional nitrogen-containing precursors or post-treatment. The SnO₂/GN exhibited a 3D hierarchical porous architecture with a large surface area (336 m²g^‑1), which not only effectively prevented the agglomeration of SnO₂ but also facilitated fast ion and electron transport through 3D pathways. As a result, the optimized electrode with GN content of 44.23% exhibited superior rate capability (1126, 855, and 614 mAh g^‑1 at 1000, 3000, and 6000 mA g^‑1, respectively) and extraordinary prolonged cycling stability at high current densities (905 mAh g^‑1 after 1000 cycles at 2000 mA g^‑1). Electrochemical impedance spectroscopy (EIS) and morphological study demonstrated the enhanced electrochemical reactivity and good structural stability of the electrode

Template-Free Synthesis of Hollow/Porous Organosilica–Fe₃O₄ Hybrid Nanocapsules toward Magnetic Resonance Imaging-Guided High-Intensity Focused Ultrasound Therapy

Entirely differing from the common templating-based multistep strategy for fabricating multifunctional hollow mesoporous silica nanoparticles (HMSN), a facile and template-free synthetic strategy has been established to construct a unique hollow/mesoporous organosilica nanocapsule (OSNC) concurrently encapsulating both isopentyl acetate (PeA) liquid and superparamagnetic iron oxides inside (denoted as PeA@OSNC). This novel material exhibits ultrasmall and uniform particle size (∼82 nm), high surface area (∼534 m²·g^–1), and excellent colloidal stability in aqueous solution. The oil-phase PeA with relatively low boiling point (142 °C) and high volatility not only plays a crucial role in formation of a large hollow cavity from the viewpoint of structural design but also enables the PeA@OSNC to act as an efficient enhancement agent in high-intensity focused ultrasound (HIFU) therapy. Moreover, the unique satellite-like distribution of Fe₃O₄ nanoparticles (NP) on the organosilica shell offered excellent magnetic resonance imaging (MRI) contrast capability of PeA@OSNC in vitro and in vivo. More importantly, such a novel theranostic agent has favorable biosafety, which is very promising for future clinical application in MRI-guided HIFU therapy

“Manganese Extraction” Strategy Enables Tumor-Sensitive Biodegradability and Theranostics of Nanoparticles

Biodegradability of inorganic nanoparticles is one of the most critical issues in their further clinical translations. In this work, a novel “metal ion-doping” approach has been developed to endow inorganic mesoporous silica-based nanoparticles with tumor-sensitive biodegradation and theranostic functions, simply by topological transformation of mesoporous silica to metal-doped composite nanoformulations. “Manganese extraction” sensitive to tumor microenvironment was enabled in manganese-doped hollow mesoporous silica nanoparticles (designated as Mn-HMSNs) to fast promote the disintegration and biodegradation of Mn-HMSNs, further accelerating the breakage of Si–O–Si bonds within the framework. The fast biodegradation of Mn-HMSNs sensitive to mild acidic and reducing microenvironment of tumor resulted in much accelerated anticancer drug releasing and enhanced T₁-weighted magnetic resonance imaging of tumor. A high tumor-inhibition effect was simultaneously achieved by anticancer drug delivery mediated by PEGylated Mn-HMSNs, and the high biocompatibility of composite nanosystems was systematically demonstrated in vivo. This is the first demonstration of biodegradable inorganic mesoporous nanosystems with specific biodegradation behavior sensitive to tumor microenvironment, which also provides a feasible approach to realize the on-demand biodegradation of inorganic nanomaterials simply by “metal ion-doping” strategy, paving the way to solve the critical low-biodegradation issue of inorganic drug carriers

High Performance and Enhanced Durability of Thermochromic Films Using VO₂@ZnO Core–Shell Nanoparticles

For VO₂-based thermochromic smart windows, high luminous transmittance (<i>T</i>_lum) and solar regulation efficiency (Δ<i>T</i>_sol) are usually pursued as the most critical issues, which have been discussed in numerous researches. However, environmental durability, which has rarely been considered, is also so vital for practical application because it determines lifetime and cycle times of smart windows. In this paper, we report novel VO₂@ZnO core–shell nanoparticles with ultrahigh durability as well as improved thermochromic performance. The VO₂@ZnO nanoparticles-based thermochromic film exhibits a robust durability that the Δ<i>T</i>_sol keeps 77% (from 19.1% to 14.7%) after 10³ hours in a hyperthermal and humid environment, while a relevant property of uncoated VO₂ nanoparticles-based film badly deteriorates after 30 h. Meanwhile, compared with the uncoated VO₂-based film, the VO₂@ZnO-based film demonstrates an 11.0% increase (from 17.2% to 19.1%) in Δ<i>T</i>_sol and a 31.1% increase (from 38.9% to 51.0%) in <i>T</i>_lum. Such integrated thermochromic performance expresses good potential for practical application of VO₂-based smart windows

Ca-α-SiAlON:Eu Phosphors: Oxidation States, Energy Transfer, and Emission Enhancement by Incorporation-Aimed Surface Engineering

Ca-α-SiAlON:Eu is one of the most promising phosphors exhibiting potential applications in high power LEDs owing to its excellent thermal stability and relatively high luminescence efficiency comparable to YAG:Ce commercial phosphors. The oxidation states of Eu ions in Ca-α-SiAlON:Eu are still questionable, and furthermore it exhibits lower luminescence intensity than commercial yellow phosphors. Therefore, in the present work, the valences of Eu ions in Ca-α-SiAlON have been examined, from which a mixture of divalence and trivalence is observed. Further improvement in emission intensity involves finding a way to increase the incorporation of larger Eu ions into the Ca-α-SiAlON. Here, we observed preferred doping of Eu around phosphor grain surface and then propose a surface engineering strategy involving HF pickling of glassy surface layer, formation of Eu-rich precursors, and finally post-annealing, aiming to increase surface incorporation of Eu ions. The surface engineered samples exhibit great enhancement in emission intensity with a maximum increment by 80%

Hierarchical Hollow Microspheres Constructed by Carbon Skeleton Supported TiO_2–<i>x</i> Few-Layer Nanosheets Enable High Rate Capability and Excellent Cycling Stability for Lithium Storage

Rational design and facile synthesis of TiO₂ based hybrid electrodes with hierarchical microstructure have great advantages for exploration of advanced electrodes for lithium-ion batteries (LIBs). We design and synthesize hierarchical hollow microspheres with inner carbon skeleton supported outer TiO_2–<i>x</i> few-layer nanosheets (C@TiO_2–<i>x</i>). The “core–shell” C@TiO_2–<i>x</i> microspheres exhibit relatively high specific surface area and a remarkable electric conductivity (0.264 μS cm^–1). The lithium kinetics of C@TiO_2–<i>x</i> microspheres is significantly improved due to synergistic effects of few-layer TiO_2–<i>x</i> nanosheets and conductive carbon skeleton. The C@TiO_2–<i>x</i> microspheres manifest an excellent reversible capacity of 323 mAh g^–1, together with an ultralong cycling lifetime that the capacity shows ∼220 mAh g^–1 after 1000 cycles at 1.0 C. The C@TiO_2–<i>x</i> microspheres also deliver a relatively high performance in rate capacity (108 mAh g^–1 at 20 C). When they are assembled into a hybrid lithium-ion capacitor, relatively high capacitance of 58 F g^–1 is achieved so that high power density reaches 14 kW kg^–1