金属元素替换对锌-铜基金属有机骨架材料的光吸收与能带特性的影响

选择常规的锌、铜作为金属离子、对苯二甲酸（BDC）作为有机配体，通过溶剂热法和元素替换法合成出Zn-Cu基MOFs材料。通过XRD、UV-Vis DRS、SEM、FT-IR、UPS和XPS等手段表征和研究，发现Zn（BDC）的光吸收位于紫外光波段（<400 nm），而Cu（BDC）光吸收拓宽至整个可见光波段（500~1 000 nm）。Zn-Cu金属离子均匀分散的产物Zn-Cu-BDC比其它产物具有更宽的光吸收范围、强度和更窄的带隙；不同的合成途径导致Zn-Cu基MOFs材料表现出性质差异。     

Efficient alternative for the reduction of N-trichloroacetyl groups in synthetic chondroitin oligosaccharide intermediates

An efficient alternative for the reduction of N-trichloroacetyl groups in chondroitin oligosaccharides is reported. It involves the use of Zn-Cu couple in acetic acid, and was successfully applied to a large panel of synthetic intermediates useful for the preparation of chondroitin oligomers, a class of natural products with numerous relevant biological functions.     

Zn-Cu-codoped SnO_2 nanoparticles: Structural,optical, and ferromagnetic behaviors

Zn–Cu-codoped SnO_2 nanoparticles have been synthesized by chemical precipitation method. All nanoparticles are crystalline, with the average size increases from 2.55 nm to 4.13 nm as the calcination temperature increases from 400℃ to 600℃. The high calcination temperature can enhance the crystalline quality and grain growth. The oxygen content decreases with decreasing calcination temperature; at a low temperature of 400℃, Zn–Cu-codoped SnO_2 nanoparticles are in a rather oxygen-poor state having many oxygen vacancies. The optical band gap energies of Zn–Cu-codoped SnO_2 nanoparticles calcined at 400℃ and 600℃ are decreased from 3.93 eV to 3.62 eV due to quantum confinement effects.Both samples exhibit room-temperature ferromagnetism, with a larger saturation magnetization at 400℃ due to the presence of large density of defects such as oxygen vacancies. Zn–Cu-codoped SnO_2 nanoparticles exhibit large optical band gap energies and room temperature ferromagnetism, which make them potential candidates for applications in optoelectronics and spintronics.