- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Selective Functionalization of High-Resolution Cu2O Nanopatterns via Galvanic Replacement for Highly Enhanced Gas Sensing Performance
摘要： Recently, high-resolution patterned metal oxide semiconductors (MOS) have gained considerable attention for enhanced gas sensing performance due to their polycrystalline nature, ultrasmall grain size (~5 nm), patternable properties, and high surface-to-volume ratio. Herein, we significantly enhanced the sensing performance of that patterned MOS by galvanic replacement, which allows for selective functionalization on ultrathin Cu2O nanopatterns. Based on the reduction potential energy difference between the base channel material (Cu2O) and the decorated metal ion (Pt2+), Pt could be selectively and precisely decorated onto the desired area of the Cu2O nanochannel array. Overall, the Pt-decorated Cu2O exhibited 11-fold higher NO2 (100 ppm) sensing sensitivity as compared to the non-decorated sensing channel, the while the channel device with excessive Pt doping showed complete loss of sensing properties.
关键词： galvanic replacement,chemical sensitization,p-type metal oxide,gas sensor,high-resolution,nanopattern
更新于2025-09-23 15:23:52
-
Preparation of composite Ag@Au core–shell nanoparticles and their linear and nonlinear optical properties
摘要： We herein report the preparation of composite Ag@Au core–shell nanoparticles (NPs) through galvanic replacement reaction and the investigations of linear and nonlinear optical properties. TEM micrographs envisage the formation of core–shell NPs. EDS elemental mapping images demonstrate the homogeneous distribution of the elements and their chemical composition. The powder XRD pattern confirms the formation of highly crystalline composite Ag@Au core–shell NPs. The UV–Vis absorption spectrum shows contribution of Ag and Au characteristic absorption bands and the slight red shift provides the strong evidence for coating of Au shell over the Ag core. Moreover, the linear optical parameters such as the extinction coefficient, reflectance, refractive index, conductivity, susceptibility and polarizability are studied. z-scan analysis reveals the enhanced nonlinear optical properties of the composite Ag@Au core–shell NPs with nonlinear refraction coefficient (n2) being ten times higher than that of Ag NPs and eight times increase in comparison with that of Au NPs.
关键词： Nonlinear optical properties,Ag@Au core–shell nanoparticles,z-scan technique,Galvanic replacement reaction,Linear optical properties
更新于2025-09-23 15:21:21
-
Enhancing Galvanic Replacement in Plasmonic Hollow Nanoparticles: Understanding the Role of the Speciation of Metal Ion Precursors
摘要： Hollow nanostructures offer great potential for plasmonic applications due to their strong and highly tunable localized surface plasmon resonance. The relationship between the plasmonic properties and geometry of hollow nanoparticles, such as core-shell size ratio, concentricity of the cavity and porosity of the wall, is well documented. Nanoscale galvanic replacement provides a simple, versatile and powerful route for the preparation of such hollow structures. Here we demonstrate how the efficiency of reductant-assisted galvanic replacement processes can be enhanced by controlling the degree of hydration and hydrolysis of the metal ion precursor using pH and pL as key control parameters (by analogy to pH, the letter p in the expression pL is used to indicate the decimal cologarithm associated with the concentration of the ligand L). Adjusting precursor speciation prior to the sacrificial template’s hollowing process offers a new strategy to tune the morphology and optical properties of plasmonic hollow nanostructures.
关键词： co-reduction,localized surface plasmon resonance,nanoscale galvanic replacement,hollow nanoparticle synthesis,Ag-Au, Ag-Pd and Ag-Pt alloys,aqueous metal ion speciation
更新于2025-09-23 15:21:01
-
Non-Recurring Circuit Nanozymatic Enhancement of Hypoxic Pancreatic Cancer Phototherapy Using Speckled Ru-Te Hollow Nanorods
摘要： Nanozymatic reactions that produce or consume oxygen (O2) or reactive oxygen species (ROS) consist of oxidase, peroxidase, superoxide dismutase (SOD), and catalase-type activity. Although extensive studies were conducted to overcome hypoxia through nanozymatic reactions, the construction of an ideal system is challenging, given that the reactants and products are arranged in a recurring structure for continuous consumption in a full cycle. In this study, speckled Ru-Te hollow nanorods were prepared through solvothermal galvanic replacement against Te nanorod templates with high yield and robustness. From their multi-compositional characteristics, non-recurring peroxidase-SOD-catalase-type nanozymatic properties were identified with photothermal and photodynamic feasibility over a wide range of laser irradiation wavelengths. Owing to the excellent colloidal stability and biocompatibility, the proposed Ru-Te based nanozymatic platform was highly effective in hypoxic pancreatic cancer phototherapy in vitro and in vivo by near infrared laser irradiation mediated photothermal and photodynamic combination treatment.
关键词： nanozyme,galvanic replacement,phototherapy,hypoxia,ruthenium
更新于2025-09-23 15:19:57
-
Decoration of plasmonic Mg nanoparticles by partial galvanic replacement
摘要： Plasmonic structures have attracted much interest in science and engineering disciplines, exploring a myriad of potential applications owing to their strong light-matter interactions. Recently, the plasmonic concentration of energy in subwavelength volumes has been used to initiate chemical reactions, for instance by combining plasmonic materials with catalytic metals. In this work, we demonstrate that plasmonic nanoparticles of earth-abundant Mg can undergo galvanic replacement in a nonaqueous solvent to produce decorated structures. This method yields bimetallic architectures where partially oxidized 200–300 nm Mg nanoplates and nanorods support many smaller Au, Ag, Pd, or Fe nanoparticles, with potential for a stepwise process introducing multiple decoration compositions on a single Mg particle. We investigated this mechanism by electron-beam imaging and local composition mapping with energy-dispersive X-ray spectroscopy as well as, at the ensemble level, by inductively coupled plasma mass spectrometry. High-resolution scanning transmission electron microscopy further supported the bimetallic nature of the particles and provided details of the interface geometry, which includes a Mg oxide separation layer between Mg and the other metal. Depending on the composition of the metallic decorations, strong plasmonic optical signals characteristic of plasmon resonances were observed in the bulk with ultraviolet-visible spectrometry and at the single particle level with darkfield scattering. These novel bimetallic and multimetallic designs open up an exciting array of applications where one or multiple plasmonic structures could interact in the near-field of earth-abundant Mg and couple with catalytic nanoparticles for applications in sensing and plasmon-assisted catalysis.
关键词： galvanic replacement,sensing,plasmon-assisted catalysis,plasmonic,Mg nanoparticles,multimetallic,bimetallic
更新于2025-09-12 10:27:22
-
Copper-surrogated galvanic displacement of silver dendrite imprinted on flexible and transparent silk fibroin membrane as a SERS-active substrate and sub-dividable catalyst
摘要： By employing copper grid as a surrogate agent, we present a facial, reagent-free and cost-e?ective approach to imprint the exquisite silver dendroid nanostructures on ?exible silk ?broin membrane, which double roles as both optical enhancers and catalytic-active sites over many chemical reactions. Unlike the conventional rigid substrates, this hybrid Ag/protein composite exhibits many previous-inaccessible properties of ?exibility, transparency, biocompatibility, molecular permeability and optical manipulation. The galvanic displacement was facilitated by a high pressure uv-lamp illumination (365 nm), shortening the dendroid growth time to be within a few minutes. The resulting substrate was characterized by microscopic image, revealing a decent 3D Ag dendrite architecture and interpenetrated crystal network, which arguably enlarged the entire surface area and keenly regulated the optical/electric property of ?brillated protein ?lm. The underlying principle of copper-initiated silver reduction and growth of crystal structure was discoursed and veri?ed with in-situ spectroscopic interrogation. Moreover, our comprehensive study supports that sub-dividable substrate enables to perform catalytic reaction under a wide range of conditions. This exploration renders a thrust to expand biopolymeric membrane into a wide breadth of applications of bendable devices through chemical modi?cations, exhaustively and economically.
关键词： Galvanic replacement,Surface-enhanced Raman scattering,Sub-dividable catalyst,Silk membrane,Plasmon-driven photo-reduction
更新于2025-09-10 09:29:36
-
Vapreotide-Mediated Hierarchical Mineralized Au/Ag nanoshells for Photothermal Anti-Tumor Therapy
摘要： A new type of vapreotide-template Ag/Au bimetallic nanoshells (Vap@Ag/AuNSs) were successfully designed and fabricated based on polypeptide-directed mineralization and hierarchical self-assembly mechanisms under mild synthetic conditions. The nanoparticles with polypeptides serving as a core and coating Ag/Au bimetallic nanoshells exhibit diverse advantages such as excellent biocompatibility, tumor targeting and low-cost. The Vap@Ag/AuNSs share excellent dispersibility, uniform size (120 nm) and a positive zeta potential (36.74±4.49 mV), hence they easily accumulate in negatively charged tumor tissue. The results of thermal imaging, temperature variation assay and photothermal conversion efficiency (41.6%) indicated that Vap@Ag/AuNSs have excellent photothermal conversion capability. Based on their photothermal response as well as biocompatibility determined by MTT assay, the prominent anti-tumor effects of Vap@Ag/AuNSs have been verified by fluorescein diacetate staining. Therefore, Vap@Ag/AuNSs are novel and promising candidates for photothermal tumor therapy.
关键词： Vapreotide-templated Au/Ag nanoshells,Biocompatibility,Photothermal therapy,Galvanic replacement,Anti-Tumor Therapy
更新于2025-09-10 09:29:36
-
Transformation of single Ag nanowires into super-large AgAu elliptic rings via a water/oil interface-oriented asymmetrical etching
摘要： Nanoring as one of fascinating geometries exhibits unique size-dependent physical-chemistry properties endowed by its circular feature. However, to the best of our knowledge, super-large elliptical nanorings cannot be fabricated by the existing techniques. Herein, we successfully fabricate super-large elliptical AgAu nanorings creatively by splitting single Ag nanowires along their longitudinal axes involving oil/water interfacial self-assembly of Ag nanowires and the galvanic replacement between interfacial Ag nanowires and AuCl4? located in the water phase. The formation of AgAu nanoring is mainly attributed to the local nanomasking of Au atoms and asymmetrical etching on interfacial Ag nanowire. Additionally, as-prepared super-large elliptical AgAu nanorings with rough surfaces exhibit enhanced catalytic performance towards the reduction of p-nitrophenol due to the combination of the composition and structure effects. This strategy, without doubt, provides a convenient way for precisely carving nanoparticles, and has the potential for processing other metallic or non-metallic nanoparticles.
关键词： Ag nanowire,selective etching,AgAu nanoring,galvanic replacement,self-assembly
更新于2025-09-09 09:28:46