摘要
采用油胺为还原剂和稳定剂,通过晶种生长法制备了Au-Pt海胆状纳米结构,研究了各种合成条件对产物结构及形貌的影响。结果表明,空气气氛下不能合成Au-Pt双金属杂聚体结构;Pt(acac)2和H2PtCl6·6H2O两种Pt前体对于产物形貌没有明显影响;强极性的1-十八烯参与合成反应时不易得到海胆状的双金属结构;不同Au/Pt配比对产物形貌影响的研究指出,Au-Pt海胆状杂聚体结构的形成是因为后还原的Pt会倾向性地沉积到先还原成核的Au纳米颗粒的特定表面。一锅法合成得到了AuPt合金结构,表明后还原的Pt以Au为晶种,在小尺寸效应作用下使颗粒发生纳米尺度的原子扩散形成了带浓度梯度的AuPt合金。
Au-Pt urchin-like heteroaggregate NPs were synthesized by oleylamine sequential reduction method.The effect of synthesis detail on the formation of Au-Pt urchin-like structures was discussed.It was found that nitrogen protection was required for successful synthesis of Au-Pt dendritic structure and there is no obvious structure change by using Pt(acac)2or H2PtCl6·6H2O.Decahydronaphthalene and 1-octadecene were used as solvents to investigate solvent effect on the formation of urchin-like structures.It was found that 1-octadecene was not suitable for synthesis of Au-Pt urchin-like structures.Through comparison of HRTEM images of AuPt urchin-like NPs at different Au/Pt ratios,it was found that Pt preferred to deposit on certain Au surface.Pt nanoislands on Au surfaces were formed at lower ratio of Pt/Au,and continuous Pt growth resulted in Au-Pt urchin-like heteroaggregate structures.In the one-pot synthesis Au seed NPs were synthesized before Pt reduction,the formation of AuPt alloy structure rather than Au-Pt urchin-like structures was attributed to be small size of Au seeds.
引文
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