金银合金纳米颗粒的可控合成及其光催化性能

以果糖为还原剂和表面活性剂，可控合成了平均粒径小于14.6nm的金银（Au-Ag）合金纳米颗粒.基于一步法，改变合成时间（1~8min），Au-Ag合金纳米颗粒的成分及其表面等离子共振（SPR）波长被连续调控.采用UV-Vis、EDX、ICP、XPS、TEM、HR-TEM和SAED等分析手段对Au-Ag合金纳米颗粒进行表征，发现制备的合金纳米颗粒具有均匀的成分和合金结构.由于Au、Ag两元素的协同作用，Au-Ag合金纳米颗粒在4-硝基苯酚的光催化降解反应中表现出了优异的光催化活性和稳定性.除了改变Au-Ag合金纳米颗粒的添加量，光催化反应的动力学速率常数还可通过改变合金成分来线性调节.基于可控合成，动力学速率常数甚至可通过Au-Ag合金纳米颗粒的合成时间来线性调控.上述控制动力学速率常数的方法可为其他的光催化反应提供参考.

Controllable synthesis of Au-Ag alloy nanoparticles and their photocatalytic properties

Au-Ag alloy nanoparticles (NPs) less than 14.6nm in size were synthesized using fructose as reductant and surfactant. Au-Ag alloy NPs were continuously obtained by changing the synthesis time from 1 to 8 min in one-pot. Au-Ag alloy NPs were characterized by means of UV-Vis, EDX, ICP, XPS, TEM, HR-TEM and SAED analyses. It was found that Au-Ag alloy NPs had homogeneous composition and alloy microstructure. As-prepared Au-Ag alloy NPs exhibited a superior photocatalytic activity and stability for 4-nitrophenol degradation due to the synergistic effect between Au and Ag elements. The kinetic rate constant of 4-nitrophenol degradation could be controlled linearly by the composition of Au-Ag alloy NPs besides their addition amount. Based on the controllable synthesis of Au-Ag alloy NPs, the kinetic rate constant could even be adjusted linearly by their synthesis time. The above methods to control the kinetic rate constant provide promising routes for other photocatalytic reactions.