Abstract—

Au nanoparticles (NPs) prepared under different molar ratio (concentration) of polyoxometalate Na₁₀SiW₉O₃₄ ⋅ 18H₂O (SiW₉) at definite concentrations of Au^III (0.15 mM), NaOH (1.5 mM), and ascorbic acid (0.225 mM) have been investigated systematically and quantitatively. The size of Au NPs decreases from 81.5 nm to 30.0 nm when the molar ratio of SiW₉ increases from 1 to 22, which is related to the activity of Auric precursor in reaction solution. It has been identified that the introduction of SiW₉ generates a new complex (expressed as Au^III−SiW₉) which is more active than the precursor of Auric hydroxide. Therefore, there is a competing equilibrium between Auric hydroxide and Au^III–SiW₉ complex in the reaction system. The increasing Au^III–SiW₉ complex results in increasing reaction rate and decreasing Au nanoparticle size, while the increasing Auric hydroxide provides a contrary result. This work represents an approach to tune the size of Au NPs by changing the molar ratio of polyoxometalate SiW₉ at a stationary Au^III concentration (0.15 mM) in the ascorbic acid reduction method. The resulting NPs capped by SiW₉ are expected a functionalized prospect due to not only the synergism of POM and Au NPs but also the strong coordination ability of POM which makes it continue to be modified.

中文翻译：

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单分散金纳米粒子的尺寸控制：多金属氧酸盐[SiW 9 O 34] 10–的控制作用

摘要—

的Au纳米颗粒（NP）多金属氧酸盐的不同的摩尔比（浓度）下制备的Na ₁₀硅钨酸₉ ö ₃₄ ⋅18H ₂ O（硅钨酸₉）在Au中的明确的浓度^III（0.15毫摩尔），氢氧化钠（1.5毫摩尔），和抗坏血酸（已对系统进行了0.225 mM）的定量研究。当SiW ₉的摩尔比从1增加到22时，Au NP的尺寸从81.5 nm减小到30.0 nm ，这与反应溶液中Auric前体的活性有关。已经确定的是，引入SiW _9会产生新的络合物（表示为Au ^III -SiW ₉），它比氢氧化金的前体更具活性。因此，在反应体系中氢氧化金和Au ^III -SiW ₉络合物之间存在竞争平衡。增加的Au ^III –SiW _9配合物导致反应速率增加和Au纳米颗粒尺寸减小，而氢氧化金增加则提供相反的结果。这项工作代表了一种通过抗坏血酸还原法改变固定的Au ^III浓度（0.15 mM）下多金属氧酸盐SiW ₉的摩尔比来调节Au NPs尺寸的方法。由SiW ₉限制的结果NP 由于POM和Au NP的协同作用以及POM强大的配位能力，使得POM和Au NPs不断被修饰，因此有望实现功能化。