双功能Ag@Pd-Ag纳米立方体原位SERS监测一锅串联反应
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- 英文论文题名：In-Situ SERS Monitoring of One-Pot Tandem Reaction with Ag@Pd-Ag nanocubes as a Dual Catalyst
- 论文作者：李菊梅 ; 秦冬
- 英文论文作者：Jumei Li ; Dong Qin ; School of Materials Science and Engineering ; Jingdezhen Ceramic Institute ; School of Materials Science and Engineering ; Georgia Institute of Technology
- 年：2016
- 作者机构：景德镇陶瓷大学材料科学与工程学院;美国佐治亚理工学院材料科学与工程学院;
- 论文关键词：表面增强拉曼光谱 ; 钯催化还原 ; 银催化氧化
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第三十七分会：纳米催化
- 语种：中文
- 分类号：O643.32
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第三十七分会 ; 纳米催化
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：2
- 文件大小：261k
- 原文格式：D
- 会议级别：全国
摘要
我们以银纳米立方体为模板、抗坏血酸为还原剂、PVP为稳定剂,在室温下采用共滴定NaPdCl_4和AgNO_3溶液,同时沉积Pd和Ag原子到银纳米立方体表面,得到了Ag@Pd-Ag纳米立方体。通过调节NaPdCl_4和AgNO_3溶液的用量和比例,可以调控Ag@Pd-Ag粒子中Pd的含量,从而优化Ag@Pd-Ag的表面增强拉曼光谱(SERS)和催化性能。以Ag@Pd-Ag作为催化剂和SERS基底,我们利用SERS原位监测4-硝基苯硫酚(4-NTP)在NaBH4溶液中的反应过程,随着时间变化的系列SERS光谱惊奇的揭示该反应过程存在三个阶段:(1)Pd催化氢气还原4-NTP为4-氨基苯硫酚(4-ATP),(2)在氢气氛围中4-ATP的稳定期,(3)Ag催化空气中氧气氧化4-ATP二聚为偶氮衍生物(4,4'-DMAB)。该结果表明Ag@Pd-Ag为同时具有Pd催化还原和Ag催化氧化特性的双功能催化剂,成功的在一锅反应中通过两个串联反应实现了从4-NTP直接合成4,4'-DMAB。该研究表明Pd和Ag的双金属催化剂将有望直接催化从硝基芳香烃合成偶氮芳香化合物。
Ag@Pd-Ag nanocubes were facilely generated by co-depositing Pd and Ag onto the surface of Ag nanocubes at room temperature. By maneuvering the ratio of Pd to Ag, we could optimize the SERS and catalytic activities of the Ag@Pd-Ag nanocubes. By using Ag@Pd-Ag nanocubes as a dual catalyst and an active SERS substrate, we observed the in-situ SERS monitoring for the production of 4,4'-dimercaptoazobezene(4,4'-DMAB) from 4-nitrothiophenol(4-NTP) through one-pot tandem reaction under ambient condition. Our time-resolved SERS spectra reveals three sequential processes that include the Pd-catalyzed reduction of 4-nitrothiophenol to 4-aminethiophenol by hydrogen, a period during which the 4-aminothiophenol remain unchanged until all hydrogen has depleted, and the Ag-catalyzed oxidation of 4-aminothiphenol to 4,4'-dimercaptoazobezene by the O_2 from air. This work demonstrates that the interplay of Pd and Ag catalysts would embrace a great promise for producing aromatic azo compounds through nitroaromatics.
Ag@Pd-Ag nanocubes were facilely generated by co-depositing Pd and Ag onto the surface of Ag nanocubes at room temperature. By maneuvering the ratio of Pd to Ag, we could optimize the SERS and catalytic activities of the Ag@Pd-Ag nanocubes. By using Ag@Pd-Ag nanocubes as a dual catalyst and an active SERS substrate, we observed the in-situ SERS monitoring for the production of 4,4'-dimercaptoazobezene(4,4'-DMAB) from 4-nitrothiophenol(4-NTP) through one-pot tandem reaction under ambient condition. Our time-resolved SERS spectra reveals three sequential processes that include the Pd-catalyzed reduction of 4-nitrothiophenol to 4-aminethiophenol by hydrogen, a period during which the 4-aminothiophenol remain unchanged until all hydrogen has depleted, and the Ag-catalyzed oxidation of 4-aminothiphenol to 4,4'-dimercaptoazobezene by the O_2 from air. This work demonstrates that the interplay of Pd and Ag catalysts would embrace a great promise for producing aromatic azo compounds through nitroaromatics.
引文
[1].Li,J.;Sun,X.;Qin,D.ChemN ano Mat DOI:10.1002/cnma.201600080,2016
[2].Li,J.;Liu,J.;Yang,Y.;Qin,D.Journal of the American Chemical Society,2015,137,7039-7042.
[2].Li,J.;Liu,J.;Yang,Y.;Qin,D.Journal of the American Chemical Society,2015,137,7039-7042.