AgAu Nanotubes: Investigating the Effect of Surface Morphologies and Optical Properties over Applications in Catalysis and Photocatalysis


J. Braz. Chem. Soc.




We herein report the preparation of AgAu nanotubes displaying controlled surface morphologies and optical properties by varying the reaction temperature during the galvanic reaction between Ag nanowires and AuCl4-(aq). As the AgAu nanotubes presented similar sizes and compositions, they enabled us to isolate the influence of surface morphology and optical properties over their catalytic and plasmonic photocatalytic activities towards methylene blue oxidation. At 25 °C, AgAu nanotubes (AgAu 25) presented branched walls and surface plasmon resonance (SPR) band with low intensities in the visible were obtained. However, at 100 °C, the AgAu nanotubes (AgAu 100) presented smooth surfaces and SPR bands that closely matched the emission spectra of a commercial halogen-tungsten lamp. The AgAu 25 nanotubes displayed better catalytic performances in classical heterogeneous catalysis as a result of its branched walls that lead to increased surface areas relative to the smooth nanotubes. Conversely, AgAu 100 nanotubes showed better activities in plasmonic photocatalysis due to its broader and more intense SPR bands. Thus, our results demonstrate the potential of the control over morphological and optical features towards the optimization of distinct catalytic phenomena.

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