Mapping the Inhomogeneity in Plasmonic Catalysis on Supported Gold Nanoparticles Using Surface-Enhanced Raman Scattering Microspectroscopy

  • The characterization of a catalyst often occurs by averaging over large areas of the catalyst material. On the other hand, optical probing is easily achieved at a resolution at the micrometer scale, specifically in microspectroscopy. Here, using surface-enhanced Raman scattering (SERS) mapping of larger areas with micrometer-sized spots that contain tens to hundreds of supported gold nanoparticles each, the photoinduced dimerization of p-aminothiophenol (PATP) to 4,4′-dimercaptoazobenzene (DMAB) was monitored. The mapping data reveal an inhomogeneous distribution of catalytic activity in the plasmon-catalyzed reaction in spite of a very homogeneous plasmonic enhancement of the optical signals in SERS. The results lead to the conclusion that only a fraction of the nanostructures may be responsible for a high catalytic activity. The high spot-to-spot variation in catalytic activity is also demonstrated for DMAB formation by the plasmon-catalyzed reduction from p-nitrothiophenol (PNTP)The characterization of a catalyst often occurs by averaging over large areas of the catalyst material. On the other hand, optical probing is easily achieved at a resolution at the micrometer scale, specifically in microspectroscopy. Here, using surface-enhanced Raman scattering (SERS) mapping of larger areas with micrometer-sized spots that contain tens to hundreds of supported gold nanoparticles each, the photoinduced dimerization of p-aminothiophenol (PATP) to 4,4′-dimercaptoazobenzene (DMAB) was monitored. The mapping data reveal an inhomogeneous distribution of catalytic activity in the plasmon-catalyzed reaction in spite of a very homogeneous plasmonic enhancement of the optical signals in SERS. The results lead to the conclusion that only a fraction of the nanostructures may be responsible for a high catalytic activity. The high spot-to-spot variation in catalytic activity is also demonstrated for DMAB formation by the plasmon-catalyzed reduction from p-nitrothiophenol (PNTP) and confirms that an improvement of the accuracy and reproducibility in the characterization of catalytic reactions can be achieved by microspectroscopic probing of many positions. Using SERS micromapping during the incubation of PATP, we demonstrate that the reaction occurs during the incubation process and is influenced by different parameters, leading to the conclusion of dimerization in a gold-catalyzed, nonphotochemical reaction as an alternative to the plasmon-catalyzed process. The results have implications for the future characterization of new catalyst materials as well as for optical sensing using plasmonic materials.zeige mehrzeige weniger

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Metadaten
Autor*innen:Janina KneippORCiD, Zhiyang Zhang
Dokumenttyp:Zeitschriftenartikel
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Analytical Chemistry
Jahr der Erstveröffentlichung:2018
Organisationseinheit der BAM:6 Materialchemie
6 Materialchemie / 6.3 Strukturanalytik
Verlag:American Chemical Society
Jahrgang/Band:90
Ausgabe/Heft:15
Erste Seite:9199
Letzte Seite:9205
DDC-Klassifikation:Naturwissenschaften und Mathematik / Chemie / Analytische Chemie
Freie Schlagwörter:AG nanoparticle; AU nanoparticle; Chemical transformation; Coupling reactions; Metal nanoparticles; Molecule; P-aminothiophenol; Sers; Silver nanoparticles; Spectroscopy
Themenfelder/Aktivitätsfelder der BAM:Chemie und Prozesstechnik
Chemie und Prozesstechnik / Chemische Charakterisierung und Spurenanalytik
DOI:10.1021/acs.analchem.8b01701
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:29.10.2018
Referierte Publikation:Ja
Datum der Eintragung als referierte Publikation:29.10.2018
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