A Dual Catalyst with SERS Activity for Probing Stepwise Reduction and Oxidation Reactions. Issue 8 (31st May 2016)

• Record Type: Journal Article
• Authors: Li, Jumei; Wu, Yiren; Sun, Xiaojun; Liu, Jingyue; Winget, Sarah A.; Qin, Dong
• Is Part Of: ChemNanoMat. Volume 2:Issue 8(2016)
• Page Start: 786
• Page End: 790
• Publication Date: 2016-05-31
• Subjects: Ag-catalyzed oxidation -- bimetallic nanocrystals -- catalysis -- Pd-catalyzed reduction; Nanochemistry -- Periodicals; Nanostructured materials -- Periodicals; Nanochemistry; Nanostructured materials; Periodicals; 541.2
• DOI: 10.1002/cnma.201600153
• Languages: English
• ISSNs: 2199-692X

Abstract

Abstract: Aromatic azo compounds are high‐value chemicals extensively used as pigments, drugs, and food additives, but their production typically requires stoichiometric amounts of environmentally unfriendly metals or nitrites. There is an urgent need to develop a dual catalytic system capable of reducing nitroaromatics to aromatic amines, followed by their oxidation to azo compounds. Here we report such a dual catalyst based on Ag@Pd‐Ag core‐frame nanocubes for the stepwise conversion of 4‐nitrothiophenol to trans ‐4, 4′‐dimercaptoazobenzene under ambient conditions. Our in situ surface‐enhanced Raman spectroscopy study reveals three sequential processes that include the Pd‐catalyzed reduction of 4‐nitrothiophenol to 4‐aminothiophenol by hydrogen, a period during which the 4‐aminothiophenol remain unchanged until all hydrogen has depleted, and the Ag‐catalyzed oxidation of 4‐aminothiophenol to trans ‐4, 4′‐dimercaptoazobenzene by the O2 from air. This work will lead to an environmentally friendly and sustainable approach to the production of aromatic azo compounds. Abstract : A dual catalyst based on Ag@Pd‐Ag core‐frame nanocubes is used to monitor the stepwise conversion of 4‐nitrothiophenol to trans ‐4, 4′‐dimercaptoazobenzene by surface enhanced Raman spectroscopy.