基于单颗粒碰撞电分析化学双模表征银包金核壳纳米材料的合成过程  

Single Nanoparticle Collision Electrochemistry for Dual-mode Characterization of Synthesis Process of Silver-coated Gold Core-shell Nanomaterials

作　　者：白乙艳 王晨阳 谈颖 徐雅琪 杨海英[1] BAI Yi-Yan;WANG Chen-Yang;TAN Ying;XU Ya-Qi;YANG Hai-Ying(Department of Chemistry,Yuncheng University,Yuncheng 044300,China)

机构地区：[1]运城学院应用化学系,运城044300

出　　处：《分析化学》2024年第12期1823-1833,共11页Chinese Journal of Analytical Chemistry

基　　金：山西省应用基础研究项目(Nos.202203021212173,202203021212175);来晋奖励项目(Nos.QZX-2022001,l2022005);山西省高等学校科技创新项目(No.2022L471);运城学院博士科研启动项目(Nos.YQ-2021032,2022001)和运城学院化学学科项目资助。

摘　　要：准确表征核壳纳米材料的合成过程对研究其结构演化规律及构效关系至关重要。本研究结合电催化型和直接电解型单颗粒碰撞的优点,构建了双模表征核壳纳米材料合成过程的新方法。基于Ag壳体积(V_(Ag))与氧化峰电量(Q)之间的定量关系,利用本方法准确地检测了不同条件下合成的银包金核壳纳米材料(Au@AgNPs)的银包覆量;同时,利用电催化放大效应对合成体系中的Au@AgNPs及小尺寸Au种和生成的Ag核进行了检测,探究了Ag壳生长方式。结果表明,当向Au种溶液中加入3.2×10^(–3)mol/L AgNO_(3)及5.3×10^(–4)mol/L柠檬酸钠溶液,并在95℃下继续反应60 min后,合成的球型Au@AgNPs的尺寸最大(d≈33 nm),此时Ag壳体积约为2.2×10^(–17)cm^(3);改变AgNO_(3)溶液浓度或柠檬酸钠溶液浓度均会影响Ag壳体积。此外,Ag^(+)还原后并不是直接沉积在Au表面,而是包含成核和聚合生长(Coalescence)两步,而且在不同阶段内成核和生长的速率不同,在0~1 min内生长速率高达1.0×10^(–17)cm^(3)/min,30~60 min内降为5.5×10^(–20)cm^(3)/min,而在60~120 min内几乎为0,符合先快后慢、最后基本不生长的规律。本研究为准确表征核壳纳米材料的合成过程提供了新思路,对精准构筑高效核壳纳米材料具有重要意义。The accurate characterization of the synthesis process of core-shell nanomaterials is crucial for studying their structural evolution and structure-activity relationships.In this work,a new method that combined the advantages of electrocatalytic and direct electrolytic single-nanoparticle collision for dual-mode characterization of the synthesis process of core-shell nanomaterials was developed.The method was used to accurately detect the Ag shell volume(V_(Ag))of Au@AgNPs synthetized at different conditions on the basis of the proportional relationship between V_(Ag)and oxidation peak charge(Q).Moreover,Au@AgNPs,small-sized Au seeds and generated Ag nuclei were detected based on the amplification of electrocatalytic single-nanoparticle collision to explore the growth mechanism of Ag shells.The results showed that when 3.2×10^(–3)mol/L of silver nitrate and 5.3×10^(–4)mol/L of sodium citrate were added to the Au seed solution,and the reaction continued at 95℃for 60 min,the largest sized spherical Au@AgNPs were synthesized(d≈33 nm),with V_(Ag)of about 2.2×10^(–17)cm^(3),and both the concentration of silver nitrate solution and sodium citrate solution affected V_(Ag).In addition,it was found that the growth of Ag shells involved nucleation and coalescence,rather than directly deposition on the surface of Au seeds after Ag+reduction.Moreover,the rates of nucleation and growth varied at different stages,reaching up to 1.0×10^(–17)cm^(3)/min in the first 1 min,decreasing to 5.5×10^(–20)cm^(3)/min within 30–60 min,and almost 0 cm^(3)/min during 60–120 min,following the pattern of being fast initially,then slowing down,and finally reaching a stagnation point.This work provided a new approach to accurately characterize the synthesis process of core-shell nanomaterials,which was of great significance for precisely constructing efficient core-shell nanomaterials.

关 键 词：核壳纳米材料 单颗粒检测 银包金 成核生长 双模 

分 类 号：TB383.1[一般工业技术—材料科学与工程] O657.1[理学—分析化学]