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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
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201605776
Subject(s) - sodium borohydride , catalysis , chemistry , borohydride , aqueous solution , reducing agent , hydrolysis , platinum , metal , nanoparticle , combinatorial chemistry , platinum nanoparticles , yield (engineering) , inorganic chemistry , photochemistry , nanotechnology , organic chemistry , materials science , metallurgy
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.