Salt-Mediated Au-Cu Nanofoam and Au-Cu-Pd Porous Macrobeam Synthesis

Burpo, F. John; Nagelli, Enoch A.; Morris, Lauren A.; Woronowicz, Kamil; Mitropoulos, Alexander N.

doi:10.3390/molecules23071701

Cited by 8 publications

(6 citation statements)

References 60 publications

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“…On the other hand, the preparation of AuCu SERS substrates typically requires the use of templates and/or high temperatures, which make synthesis methods costly and, therefore, not suitable for scale up production. Some of these methods include laser ablation [26], porous anodic aluminum oxide template method [27], nanolithography (electron-beam lithography and focused ion beam milling) [28], impregnation / calcination [19], among many others that also require long reaction times, the use of harmful organic reagents and/or high-energy [23,[29][30][31]. In such a way, the development of cost-effective preparation methods for highly active SERS substrates is a remaining goal in Raman scattering-based chemical sensing.…”

Section: Introductionmentioning

confidence: 99%

Cu@Au self-assembled nanoparticles as SERS-active substrates for (bio)molecular sensing

Cabello

Nwoko

Marco

et al. 2019

Journal of Alloys and Compounds

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Cu 0 (core)-Au 0 (shell) (Cu@Au) bimetallic nanoparticles (NPs) synthesized under microwaveassisted heating were interrogated for surface enhanced Raman scattering (SERS)-active substrates. NPs characterization, by XRD, XPS and UV/vis spectroscopy, showed the formation of self-assembled particles with the occurrence of electron transfer from Cu to Au and the absence of CuxO. TEM and AF4 demonstrated NPs with a mean diameter of 4.7 nm. Despite the low LSPR shown by small nanoparticles (< 10 nm diameter), our Cu@Au NPs showed enhanced SERS effect, demonstrated by the calculated scattering signal enhancement factor (3 x 10 5 ), which may be related to electromagnetic coupling. Selected examples of analytes of interest, including some biomolecules, were studied to demonstrate the versatility of our Cu@Au NPs as SERS-active substrates.

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Section: Introductionmentioning

confidence: 99%

Cu@Au self-assembled nanoparticles as SERS-active substrates for (bio)molecular sensing

Cabello

Nwoko

Marco

et al. 2019

Journal of Alloys and Compounds

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“…While numerous Pt-Cu nanostructures have been demonstrated, discrete nanoparticles require post-synthesis binding into functional electrodes, and there has been limited demonstration of scalable aqueous-based synthesis of porous 3-dimensional structures.Recently rapid noble metal aerogel synthesis was demonstrated via a high concentration direct reduction approach [38,39], and salt templating was used to synthesize 2-dimensional materials [40,41]. Combining the use of high salt concentrations and salt templates, our group synthesized Pt and Pt-Pd macrobeams and porous nanomaterials from Magnus's and Vauquelin's salts and derivatives [42,43], as well as salt-templated Au-Pd and Au-Cu-Pd multi-metallic porous materials [44]. Rapid precipitation of high-aspect ratio Magnus's salts [45] and Vauquelin's salts [46] results from the combination of oppositely charged square planar platinum and palladium metal ions, respectively.…”

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confidence: 99%

Salt-Templated Platinum-Copper Porous Macrobeams for Ethanol Oxidation

et al. 2019

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Platinum nanomaterials provide an excellent catalytic activity for diverse applications and given its high cost, platinum alloys and bi-metallic nanomaterials with transition metals are appealing for low cost and catalytic specificity. Here the synthesis of hierarchically porous Pt–Cu macrobeams and macrotubes templated from Magnus’s salt derivative needles is demonstrated. The metal composition was controlled through the combination of [PtCl4]2− with [Pt(NH3)4]2+ and [Cu(NH3)4]2+ ions in different ratios to form salt needle templates. Polycrystalline Pt–Cu porous macrotubes and macrobeams 10’ s–100’ s μm long with square cross-sections were formed through chemical reduction with dimethylamine borane (DMAB) and NaBH4, respectively. Specific capacitance as high as 20.7 F/g was demonstrated with cyclic voltammetry. For macrotubes and macrobeams synthesized from Pt2−:Pt2+:Cu2+ salt ratios of 1:1:0, 2:1:1, 3:1:2, and 1:0:1, DMAB reduced 3:1:2 macrotubes demonstrated the highest ethanol oxidation peak currents of 12.0 A/g at 0.5 mV/s and is attributed to the combination of a highly porous structure and platinum enriched surface. Salt templates with electrochemical reduction are suggested as a rapid, scalable, and tunable platform to achieve a wide range of 3-dimensional porous metal, alloy, and multi-metallic nanomaterials for catalysis, sensor, and energy storage applications.

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“…The cobalt ions were electrostatically bound to the anionic carboxylates throughout the organic structure and were also sequestered within the gel pores, where they were prepositioned for chemical reduction. High-concentration 2 M NaBH 4 was used for the diffusion of the reducing agent into the gel, especially given that its concentration is depleted with the reduction of Co 2+ ions, and to ensure a complete and uniform reduction throughout the gel volume [81][82][83][84]. The chemical reduction of the Co 2+ ions into cobalt metal changed the appearance of the gels from a pink hue to a black gel, as seen in Figure 1d.…”

Section: Cnf-alginate-cobalt Aerogel Synthesismentioning

confidence: 99%

Cellulose Nanofiber–Alginate Biotemplated Cobalt Composite Multifunctional Aerogels for Energy Storage Electrodes

Zhang,

Trackey,

Verma

et al. 2023

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Tunable porous composite materials to control metal and metal oxide functionalization, conductivity, pore structure, electrolyte mass transport, mechanical strength, specific surface area, and magneto-responsiveness are critical for a broad range of energy storage, catalysis, and sensing applications. Biotemplated transition metal composite aerogels present a materials approach to address this need. To demonstrate a solution-based synthesis method to develop cobalt and cobalt oxide aerogels for high surface area multifunctional energy storage electrodes, carboxymethyl cellulose nanofibers (CNF) and alginate biopolymers were mixed to form hydrogels to serve as biotemplates for cobalt nanoparticle formation via the chemical reduction of cobalt salt solutions. The CNF–alginate mixture forms a physically entangled, interpenetrating hydrogel, combining the properties of both biopolymers for monolith shape and pore size control and abundant carboxyl groups that bind metal ions to facilitate biotemplating. The CNF–alginate hydrogels were equilibrated in CaCl2 and CoCl2 salt solutions for hydrogel ionic crosslinking and the prepositioning of transition metal ions, respectively. The salt equilibrated hydrogels were chemically reduced with NaBH4, rinsed, solvent exchanged in ethanol, and supercritically dried with CO2 to form aerogels with a specific surface area of 228 m2/g. The resulting aerogels were pyrolyzed in N2 gas and thermally annealed in air to form Co and Co3O4 porous composite electrodes, respectively. The multifunctional composite aerogel’s mechanical, magnetic, and electrochemical functionality was characterized. The coercivity and specific magnetic saturation of the pyrolyzed aerogels were 312 Oe and 114 emu/gCo, respectively. The elastic moduli of the supercritically dried, pyrolyzed, and thermally oxidized aerogels were 0.58, 1.1, and 14.3 MPa, respectively. The electrochemical testing of the pyrolyzed and thermally oxidized aerogels in 1 M KOH resulted in specific capacitances of 650 F/g and 349 F/g, respectively. The rapidly synthesized, low-cost, hydrogel-based synthesis for tunable transition metal multifunctional composite aerogels is envisioned for a wide range of porous metal electrodes to address energy storage, catalysis, and sensing applications.

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Salt-Mediated Au-Cu Nanofoam and Au-Cu-Pd Porous Macrobeam Synthesis

Cited by 8 publications

References 60 publications

Cu@Au self-assembled nanoparticles as SERS-active substrates for (bio)molecular sensing

Cu@Au self-assembled nanoparticles as SERS-active substrates for (bio)molecular sensing

Salt-Templated Platinum-Copper Porous Macrobeams for Ethanol Oxidation

Cellulose Nanofiber–Alginate Biotemplated Cobalt Composite Multifunctional Aerogels for Energy Storage Electrodes

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