Triangular and Prism‐Shaped Gold‐Zinc Oxide Plasmonic Nanostructures: In situ Reduction, Assembly, and Full‐Range Photocatalytic Performance

Abstract

Gold‐based nanocatalysts have been traditionally selected for multiple homogeneous and heterogeneous reactions of interest involving redox processes. Likewise, greener routes involving more efficient reactors and the use of inexpensive and nature‐mimicking excitation sources have boosted the research on photocatalysts that can drive these chemical reactions upon excitation with multiple wavelength sources beyond the UV range. In the present work we report on a multi‐step synthesis approach that enables the in situ generation of triangular and prism‐shaped gold nanostructures with a localized surface plasmon resonance effect and their direct assembly onto a ZnO nanostructured semiconductor support. Different LED excitation sources in the whole UV/Vis‐NIR range have been systematically selected to activate these hybrid materials in the selective reduction of p‐nitrophenol (4‐NP), a well‐known contaminant by‐product. While ZnO becomes preferentially active in the UV window, the anisotropic shape of these gold plasmonic nanostructures helps to broaden the photocatalytic response of ZnO towards the visible and NIR range, being especially active under 460 nm blue light irradiation and expanding their potential application in multiple solar‐driven catalytic processes of interest for decontamination and upgrading of toxic chemicals.