State Key Laboratory of Plastic Forming Simulation and Die and Mold Technology, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China.
J Hazard Mater. 2012 May 30;217-218:36-42. doi: 10.1016/j.jhazmat.2012.01.056. Epub 2012 Mar 8.
Here we report a facile, surfactant-free and template-free synthesis process of highly uniform dendritic silver nanostructures with high catalytic activity for the reduction of p-nitrophenol. By controlling the concentration of AgNO(3) aqueous solution and the reaction time, various shapes of silver nanodendrites (SNDs) could be obtained easily. The effects of different parameters such as concentrations of the reagents and reaction time on the morphology and structure of as-prepared tree-like nanostructures have also been investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Also, the X-ray photoelectron spectroscopy (XPS) has been used to identify the oxidation state of SNDs. In addition, the catalytic activity of the as-prepared SNDs samples at 200 mM AgNO(3) aqueous solution was evaluated by a redox reaction of p-nitrophenol in the presence of an excess amount of NaBH(4). It was found that the highly symmetrical SNDs with roughly 60-120 nm in stem and branch diameter and 3-12 μm in length obtained after 120 s reaction time do have higher catalytic activity than other SNDs prepared at different reaction time, several times stronger catalytic activity in the sodium borohydride reduction of p-nitrophenol to p-aminophenol, compared to some other silver nanoparticles reported in literature. The crystallinity provided by X-ray diffraction (XRD) analysis indicates that the improvement of the crystallinity is also very crucial for SNDs' catalytic activities. The SNDs are very promising catalytic candidates for the reduction of p-nitrophenol because of easily simple preparation route and high catalytic activity.
在这里，我们报告了一种简便、无表面活性剂和无模板的方法，用于合成具有高催化活性的高度均匀的树枝状银纳米结构，用于还原对硝基苯酚。通过控制硝酸银水溶液的浓度和反应时间，可以很容易地得到各种形状的银纳米树突（SNDs）。还通过 X 射线衍射（XRD）、场发射扫描电子显微镜（FESEM）和透射电子显微镜（TEM）研究了不同参数（如试剂浓度和反应时间）对所制备的树形纳米结构的形态和结构的影响。此外，还使用 X 射线光电子能谱（XPS）来确定 SNDs 的氧化态。此外，通过在过量的硼氢化钠存在下对 p-硝基苯酚进行氧化还原反应，评估了在 200mM 硝酸银水溶液中制备的 SNDs 样品的催化活性。结果发现，在 120s 反应时间后获得的具有约 60-120nm 干和枝直径以及 3-12μm 长度的高度对称的 SNDs 具有比在不同反应时间下制备的其他 SNDs 更高的催化活性，在硼氢化钠还原对硝基苯酚生成对氨基酚的反应中具有比文献中报道的一些其他银纳米粒子高几倍的催化活性。X 射线衍射（XRD）分析的结晶度表明，结晶度的提高对 SNDs 的催化活性也非常重要。由于制备路线简单、催化活性高，SNDs 是很有前途的用于还原对硝基苯酚的催化候选物。
