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Anisotropic noble metal nanostructures have shown remarkable structural benefits in near-Infrared (NIR) light absorption and high efficiency in photothermal conversion. In this study, we employ the seed growth strategy to create two-dimensional gold (Au) in-plane hybrid nanostructures, specifically designed with numerous quasi-spherical particles adorning the edge of a single plate, showcasing promising use in NIR-II photothermal conversion. The key to our successful synthesis lies in the doping of plate-like Au seeds with elemental selenium (Se), which plays a crucial role in restricting the island-like deposition of Au nanoparticles predominantly to the edge regions. With this unique hybrid structure, we observed a notable red-shift in the absorption peak towards longer wavelengths, ensuring full coverage of the NIR-II regions. A photothermal conversion efficiency of 42% was achieved, as evaluated using a water suspension under a 1064 nm laser at a power density of 1.0 W cm−2. Furthermore, our investigation into photothermal stability revealed excellent durability even after multiple heating and cooling cycles. Finite-difference time-domain (FDTD) simulations confirm that polarization of surface charges along the edge region is achieved by constructing such a "plate@ sphere" in-plane hybrid structure, thereby affirming successful hot spot engineering. This research demonstrates the potential to manipulate the growth mode of two-dimensional Au nanostructures through non-metal doping during seeded growth and validates the use of in-plane hybrid two-dimensional nanostructures for photothermal conversion, providing insights for the rational design of high-performance NIR-II photothermal nanomaterials tailored for biomedical applications. [ABSTRACT FROM AUTHOR]

Direct formic acid fuel cells have attracted significant attention due to their low fuel crossover, high safety, and high theoretical power density among all proton‐exchange membrane fuel cells. Numerous efforts have been dedicated to studying formic acid oxidation, particularly in the fabrication of high‐performance electrocatalysts with economical utilization of Pt metal. In this work, we report a synthetic strategy to create PtAg dots supported on plate‐like Au nanoparticles and explore their applications in electrocatalytic formic acid oxidation. The highly dispersed nature of the catalytic Pt centers and the successful construction of PtAg−Au trimetallic interfaces makes the current nanostructure an ideal system to allow for a synergetic effect between Pt, Au, and Ag, leading to improved electrocatalysis. Compared with commercial Pt/C, our PtAg‐on‐Au heterogenous nanoplates exhibit superior mass activity, along with enhanced reaction kinetics and long‐term durability for FAOR in an acidic medium. Density functional theory (DFT) simulation results indicate that AgPtAu(111) exhibits a relatively high activity for HCOOH oxidation into CO2 among the various Au‐based catalysts. This work provides a viable strategy for constructing Pt‐based electrocatalysts with controlled Pt ensembles, offering insights into the development of fuel cell catalysts that make highly efficient use of costly noble metals. [ABSTRACT FROM AUTHOR]

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]

Comprehensive Summary: We present a facile synthetic strategy to create mesoporous Cu2O nanocrystals with tunable pore structures and surface functional groups of amine derivatives for efficient and preferable electrochemical conversion of CO2 into ethylene. The structural characteristics of these Cu2O nanocrystals can be manipulated using a set of amine derivatives, such as pyridine, 4,4'‐bipyridine, and hexamethylenetetramine, during the oxidative etching process of Cu nanocrystals by bubbling gaseous oxygen in N,N‐dimethylformamide solution. These amine derivatives not only serve as surface functional groups but also significantly affect the resulting pore structures. The synergistic effect of pore structure confinement and surface amine functionalization leads to the superb Faradaic efficiency (FE) of 51.9% for C2H4, respectively, together with the C2H4 partial current density of –209.4 mA·cm−2 at –0.8 V vs. reversible hydrogen electrode (RHE). The relatively high selectivity towards C2H4 was investigated using DFT simulations, where 4,4'‐bipyridine functionalized Cu2O seemed to favor the C2H4 formation with the low free energy of the intermediates. This study provides a feasible strategy to manipulate the pore structure and surface functionalization of mesoporous Cu2O nanocrystals by regulating the oxidative etching process, which sheds light on the rational preparation of high‐performance CO2RR electrocatalysts. [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]

We report a mild, one‐pot synthesis of PdPtAuAgCuIr multimetallic nanocrystals with controlled shapes and explore their applications as the electrocatalysts for ethanol electrooxidation in alkaline medium. The success of current synthesis relies on the co‐reduction of six metal precursors in the presence of octadecylammonium chloride and ascorbic acid at an elevated temperature. The resulting products are featured with an in‐plane core‐shell structure, together with the trigonal/hexagonal plate decorated with granular edges. When serving as EOR electrocatalysts, the carbon‐supported PdPtAuAgCuIr nanocrystals exhibit more than five‐fold increase in mass activity as compared to that of commercial Pt/C, as well as improved reaction kinetics and long‐term durability. DFT calculations disclose that the reduced energy barrier renders the Pd‐based multimetallic catalyst in catalytic performance. The present study provides a feasible strategy to create multimetallic nanocrystals with controlled two‐dimensional morphology under ambient conditions, shedding light for rational design over advanced fuel cell catalysts composed of multimetallic alloy. [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]

We report the preparation of plasmonic Janus nanostructures, composed of solid and hollow interiors, respectively, via a stepwise seeded growth. The success of the current synthesis highly relies on the construction of AuAg-based Janus nanocrystals with well-defined structures and the following controlled galvanic replacement reaction to prominently carve the Ag parts into hollow derivatives. With such unique architecture, they are enabled with the optical feature of dual plasmonic absorptions in the visible and near-infrared range and benefit the utilization of incident light and thus the photothermal conversion. The optimal temperature rise (ΔT) of the aqueous suspension was 15.2 °C after 10 min of 808 nm laser irradiation at a power density of 1.0 W cm–2, which was effective against multidrug-resistant bacteria in vitro. The current work shows a feasible synthetic strategy to create plasmonic Janus nanostructures featuring different porosities on each side, shedding light on rational design of advanced photothermal nanomaterials in biomedicine applications. [ABSTRACT FROM AUTHOR]