Probing oxygen activation on plasmonic photocatalysts

Fons Dingenen; Rituraj Borah; Rajeshreddy Ninakanti; Sammy W Verbruggen

doi:10.3389/fchem.2022.988542

Probing oxygen activation on plasmonic photocatalysts

Front Chem. 2022 Sep 12:10:988542. doi: 10.3389/fchem.2022.988542. eCollection 2022.

Authors

Fons Dingenen^{1

2}, Rituraj Borah^{1

2}, Rajeshreddy Ninakanti^{1

2

3}, Sammy W Verbruggen^{1

2}

Affiliations

¹ Department of Bioscience Engineering, University of Antwerp, Sustainable Energy, Air & Water Technology (DuEL), Antwerp, Belgium.
² Nanolab Center of Excellence, University of Antwerp, Antwerp, Belgium.
³ Department of Physics, Electron Microscopy for Material Science, University of Antwerpen, Antwerp, Belgium.

Abstract

In this work we present an assay to probe the oxygen activation rate on plasmonic nanoparticles under visible light. Using a superoxide-specific XTT molecular probe, the oxygen activation rate on bimetallic gold-silver "rainbow" nanoparticles with a broadband visible light (> 420 nm) response, is determined at different light intensities by measuring its conversion into the colored XTT-formazan derivate. A kinetic model is applied to enable a quantitative estimation of the rate constant, and is shown to match almost perfectly with the experimental data. Next, the broadband visible light driven oxygen activation capacity of this plasmonic rainbow system, supported on nano-sized SiO₂, is demonstrated towards the oxidation of aniline to azobenzene in DMSO. To conclude, a brief theoretical discussion is devoted to the possible mechanisms behind such plasmon-driven reactions.

Keywords: Kinetics; oxygen activation; photocatalysis; probe; surface plasmon resonance (SPR).