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Metal nanoparticles have been found to exhibit a broad spectrum of antibacterial activities, yet not all metals possess the captivating plasmonic properties necessary for effective interaction with incident light. In this study, we demonstrate the feasibility of synergistically enhancing the Cu-induced antibacterial activity through the incorporation of plasmonic photothermal therapy by hybridlike anchoring the Cu component on a gold (Au) nanoplate that can effectively absorb near-infrared light. To fabricate the Janus structure, plate-like Au seeds were mixed with copper-(ii) nitrate, cetyltrimethylammonium bromide, ascorbic acid, and hexamethylenetetramine, resulting in the formation of Au–Cu Janus nanostructures (JNSs). Notably, the plasmonic absorption of Au was preserved without being hindered by the Cu coating. Photothermal measurements revealed that the temperature rise of Au–Cu JNSs aqueous suspensions could reach up to 28.3 °C in just 10 min when exposed to 1064 nm laser light at a power density of 1 W·cm–2, with a photothermal conversion efficiency of 42.14%. Additionally, they show broad-spectrum antibacterial properties, making them potential contenders for addressing a wide range of bacterial infections. Our findings demonstrate that the antibacterial performance of metal nanoparticles composed of less plasmon-active components but with exceptional antibacterial properties can be significantly enhanced by coupling them with a plasmon-active nano-antenna through a Janus architecture. The Au–Cu JNSs possess potential application prospects in photothermal therapy, broad-spectrum antibacterial treatments, biomedical imaging, targeted drug delivery, sensitive diagnostics, and the development of advanced materials. [ABSTRACT FROM AUTHOR]

Ultrathin two-dimensional (2D) nanostructures, with superhigh exposure of the under-coordinated metal atoms relative to large-sized quasi-spherical particles or bulk counterparts, have shown enormous potential to enhance various heterogeneous catalytic reactions. The creation of in-plane holes and rational assembling of ultrathin 2D nanosheets into 3D hierarchical architectures can prevent the restacking issue of nanosheets, thereby providing more active sites by hampering atomic diffusion, nearby nanosheet aggregation, and thermodynamic structural reform. Herein, we report the stepwise construction of ultrathin CuAuAg nanosheet-assembled 3D nanoflowers (NFs). The synthesis involves the conversion of Au@CuxO mesoporous nanospheres into CuAg NFs, followed by a controlled galvanic replacement reaction with chloroauric acid to create holes and manipulate the atomic ratio between Cu, Au, and Ag. With strong broad-spectrum light absorption across the UV–vis region, the current CuAuAg NFs exhibited satisfactory photothermal conversion under Xe lamp irradiation. When serving as HER electrocatalysts, the Cu10.5Au58.4Ag31.1 NFs displayed the optimized performance in terms of overpotential and activity, surpassing the Cu71.4Ag28.6 NFs and Au NCs, which is supported by DFT simulations, showcasing the multimetallic coupling advantage for HER. This study presents a viable route to construct trimetallic 3D hierarchical nanostructures and validates their application in photothermal conversion and electrocatalytic HER, guiding the design of high-performance photosensitizers and electrocatalysts. [ABSTRACT FROM AUTHOR]

Rational assembling of different noble metal nanocrystals with controlled nanogaps in one entity allows the efficient coupling of electromagnetic fields of each component and versatile manipulation over the overall physiochemical properties. In the present study, we report a stepwise synthetic strategy to hybridlike assemble Au nanoplate and Ag nanoparticles without direct physical contact. Particularly, the success of current work relies on the conformal coating of Cu2O over the Au nanoplate as an intermediate layer, followed by the in situ formation of Ag nanoparticles via the galvanic replacement reaction between Cu2O and Ag+. With the anchoring of Ag nanoparticles over the Cu2O‐wrapped Au nanoplate, the resulting hybrid nanostructures exhibit noticeable multiple plasmonic absorptions across the UV‐vis‐NIR region. The potential use as the plasmonic catalyst for current Au@Cu2O‐Ag hybrid products is validated using reduction of 4‐nitrophenol as the model reaction, where the catalytic performance is greatly improved by the UV‐vis light irradiation. They also exhibit satisfactory photothermal conversion performance under the irradiation of Xe lamp. The current work provides a niche strategy to create noble‐metal hybrid nanostructures with controlled interparticle distance and tunable plasmonic properties, could be extended to other noble metal or alloys. [ABSTRACT FROM AUTHOR]