Local Photochemical Nanoscopy of Hot-Carrier-Driven Catalytic Reactions Using Plasmonic Nanosystems

• Published in: ACS nano 2023-06, Vol.17 (12), p.11427-11438
• Main Authors: Henrotte, Olivier, Santiago, Eva Yazmin, Movsesyan, Artur, Mascaretti, Luca, Afshar, Morteza, Minguzzi, Alessandro, Vertova, Alberto, Wang, Zhiming M., Zbořil, Radek, Kment, Štěpán, Govorov, Alexander O., Naldoni, Alberto
• Format: Article
• Language: English
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.3c01009

Nanoscale investigation of the reactivity of photocatalytic systems is crucial for their fundamental understanding and improving their design and applicability. Here, we present a photochemical nanoscopy technique that unlocks the local spatial detection of molecular products during plasmonic hot-carrier-driven photocatalytic reactions with nanometric precision. By applying the methodology to Au/TiO2 plasmonic photocatalysts, we experimentally and theoretically determined that smaller and denser Au nanoparticle arrays present lower optical contribution with quantum efficiency in hot-hole-driven photocatalysis closely related to the population heterogeneity. As expected, the highest quantum yield from a redox probe oxidation is achieved at the plasmon peak. Investigating a single plasmonic nanodiode, we unravel the areas where oxidation and reduction products are evolved with subwavelength resolution (∼200 nm), illustrating the bipolar behavior of such nanosystems. These results open the way to quantitative investigations at the nanoscale to evaluate the photocatalytic reactivity of low-dimensional materials in a variety of chemical reactions.