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Metal Nanoparticle‐Catalyzed Reduction Using Borohydride in Aqueous Media: A Kinetic Analysis of the Surface Reaction by Microfluidic SERS
Author(s) -
Xie Wei,
Grzeschik Roland,
Schlücker Sebastian
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201605776
Subject(s) - sodium borohydride , catalysis , borohydride , chemistry , aqueous solution , reducing agent , hydrolysis , platinum nanoparticles , platinum , yield (engineering) , nanoparticle , inorganic chemistry , colloid , combinatorial chemistry , photochemistry , chemical engineering , nanotechnology , organic chemistry , materials science , metallurgy , engineering
Abstract Hydrides are widely used in reduction reactions. In protic solvents, their hydrolysis generates molecular hydrogen as a second reducing agent. The competition between these two parallel reduction pathways has been overlooked so far since both typically yield the same product. We investigated the platinum‐catalyzed reduction of 4‐nitrothiophenol to 4‐aminothiophenol in aqueous sodium borohydride solution as a prominent model reaction, by using label‐free SERS monitoring in a microfluidic reactor. Kinetic analysis revealed a strong pH dependence. Surprisingly, only at pH>13 the reduction is driven exclusively by sodium borohydride. This study demonstrates the potential of microfluidics‐based kinetic SERS monitoring of heterogeneous catalysis in colloidal suspension.