Zhenguo Ji

Highly stable Y(III)-based metal organic framework with two molecular building block for selective adsorption of C2H2 and CO2 over CH4

We successfully designed and constructed a novel mircroporous metal organic framework [Y4(TATB)2]·(DMF)3.5·(H2O) (ZJU-16, H3TATB = 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzoic acid) from two different types of MBBs (molecular building block) [Y3(μ3-OH)(COO−)6] and [Y9(μ3-OH)14(COO−)12] and a tricarboxylic acid organic linker via solvothermal reaction. ZJU-16 exhibited high thermal and chemical stability; it is stable up to 500 °C and also maintains its integrity in neutral (water), basic and acidic aqueous solutions. Due to suitable pore size and high stability, the desolvated ZJU-16a demonstrates moderately high selective separation of C2H2/CH4 and CO2/CH4 at room temperature.

In-situ synthesis of carbon doped porous silicon nanocomposites as high-performance anodes for lithium-ion batteries

We demonstrate the in situ synthesis of carbon doped porous silicon (Si/C) nanocomposites by a simple thermal displacement process between Mg2Si and inorganic gas CO2 in one-step. Via the decomposition of Mg2Si, the reduction process occurred between Mg and CO2, leading the uniform doping of many distributed tiny carbon nanoparticles into Si. Meanwhile, the porous structure was formed after an acid treatment. When worked as anodes for lithium-ion batteries, the as-prepared s-porous Si/C nanocomposites exhibited good cycling stability and high-rate capability, which were superior to the porous Si and porous Si/C nanocomposites. It was revealed that the enhanced electrochemical properties could be ascribed to the novel porous structure and doped carbon nanoparticles that can buffer the volume expansion, as well as enhance the electronic conductivity of Si. The reaction mechanism was well investigated by studying the influence of reaction temperature and raw Mg2Si particle size on the morphology and component of the porous Si/C nanocomposites.

Nd3+/Yb3+ cascade-sensitized single-band red upconversion emission in active-core/active-shell nanocrystals

Lanthanide-doped upconversion nanomaterials (UCNMs) have promoted extensive interest for its biological research and biomedical applications, benefiting from low autofluorescence background, deep light penetration depth, and minimal photo-damage to biological tissues. However, owing to the 980 nm laser-induced overheating issue and the attenuation effect associated with conventional multi-peak emissions, the usage of UCNMs as fluorescent bioprobes is still limited. To address these issues, an effective strategy has been proposed to tune both the excitation and emission peaks of UCNMs into the first biological window (650xa0∼xa0900 nm), where the light absorption by water and hemoglobin in biological tissues is minimal. Based on the Nd3+/Yb3+ cascade-sensitized upconversion process and efficient exchange-energy transfer between Mn2+ and Er3+ in conjunction with the active-core@active-shell nanostructured design, we have developed a new class of upconversion nanoparticles (UCNPs) that exhibit strong single-band red emission upon excitation of an 808 nm near-infrared laser. Hopefully, the well-designed KMnF3:Yb/Er/Nd@ KMnF3:Yb/Nd core-shell nanocrystals will be considered a promising alternative to conventionally used UCNPs for biolabeling applications without the concern of the overheating issue and the attenuation constraints.

Controllable synthesis of lanthanide upconversion nanomaterials through impurity doping

Abstract Generally, electronic, magnetic, and optical properties of many technological nanomaterials are realized by purposely “doping” suitable amounts of external elements into hosts. Recently, it has been reported that impurity doping has significant influence on nucleation/growth of numerous functional nanocrystals, and affords a fundamental approach to modify the crystal phase, particle size, morphology, and electronic configuration of nanomaterials. In this chapter, an overview of the recent progress in doping-induced control of phase structures, sizes, shapes, as well as luminescence properties of upconversion (UC) nanomaterials, has been provided. Additionally, we also elucidate the control of lanthanide (Ln 3+ ) activator distribution in the core–shell structure, which has recently provided new opportunities for scientists to design and tune multicolor emissions of Ln 3+ -doped UC nanoparticles. Finally, we point out the challenges and perspectives of the developing impurity-doping strategy.

Improving the visible light photocatalytic activity of TiO{sub 2} nanotubes upon decoration with Sb{sub 2}S{sub 3} microcrystalline

Abstract TiO2 nanotube arrays sensitized with Sb2S3 microcrystalline were successfully fabricated by a two-step process of photodeposition method followed by annealing treatment. The structural investigation by X-ray diffraction, scanning electron microscopy and transmission electron microscopy indicated that the Sb2S3 microparticles grew uniformly on the walls of TiO2 nanotubes. The amorphous Sb2S3 microspheres could be transformed into octahedral microcrystals after annealing treatment. The Sb2S3 modification of the TiO2 nanotube arrays resulted in an increase in visible light adsorption and photocatalytic activities toward degradation of methyl orange (MO) and rhodamine B (RhB) dyes under visible light irradiation.