Binary Surfactant–Mediated Tunable Nanotip Growth on Gold Nanoparticles and Applications in Photothermal Catalysis

Abstract

Plasmonic nanostructures with sharp tips are widely used for optical signal enhancement because of their strong light-confining abilities. These structures have a wide range of potential applications, for example, in sensing, bioimaging, and surface-enhanced Raman scattering. Au nanoparticles, which are important plasmonic materials with high photothermal conversion efficiencies in the visible to near-infrared region, have contributed greatly to the development of photothermal catalysis. However, the existing methods for synthesizing nanostructures with tips need the assistance of poly(vinylpyrrolidone), thiols, or biomolecules. This greatly hinders signal detection because of stubborn residues. Here, we propose an efficient binary surfactant–mediated method for controlling nanotip growth on Au nanoparticle surfaces. This avoids the effects of surfactants and can be used with other Au nanostructures. The Au architecture tip growth process can be controlled well by adjusting the ratio of hexadecyltrimethylammonium bromide to hexadecyltrimethylammonium chloride. This is due to the different levels of attraction between Br−/Cl− and Au3+ ions. The surface-enhanced Raman scattering and catalytic abilities of the synthesized nanoparticles with tips were evaluated by electromagnetic simulation and photothermal catalysis experiments (with 4-nitrothiophenol). The results show good potential for use in surface-enhanced Raman scattering applications. This method provides a new strategy for designing plasmonic photothermal nanostructures for chemical and biological applications.

Plasmonic Au–Cu nanostructures: Synthesis and applications

“…The frequency of LSPR is relevant to the morphology, size and composition of the metallic nanostructure and to the dielectric constant of the medium ( Klar et al, 1998 ). For Au–Cu nanostructures, the wavelength and line shape of LSPR depends not only on their morphology and size but also on the Au and Cu elemental distribution ( Mi et al, 2021a ). Typically, this leads to a broadening of the LSPR and a well-defined redshift when the Cu content of the Au–Cu alloy nanosphere increases, as shown in Figure 4A .…”

“…It has been possible to prepare a variety of bimetallic nanostructures by using several different methods ( Feng et al, 2012 ; Lee et al, 2014 ; Zheng et al, 2020 ; Zhou L. et al, 2021 ; Zhou M. et al, 2021 ; Feng et al, 2021 ; Jiang et al, 2021 ; Skrabalak, 2021 ; Yang et al, 2021 ; Lee et al, 2022 ). Cu and Au nanostructures are excellent materials for applications in catalysis and plasmonic ( Zhang et al, 2019 ; Mi et al, 2021a ; Xin et al, 2021 ; Zhang B. et al, 2022 ; Lin et al, 2022 ). Cu nanostructures, which are valuable plasmonic materials in the visible to near-infrared region, have contributed to the development of applications in photonics, sensing, heterogeneous catalysts and imaging ( Gawande et al, 2016 ; Lee D. W. et al, 2021 ; Medvedeva et al, 2021 ).…”

Silver ions induced growth of plasmonic Au hexagonal star plates

“…Thus, Ag + can break the isotropy of the Au nanostructures during the growth process, [14][15][16][17] such as Au nanorods, Au nanoflowers, and Au bipyramids. [18][19][20][21][22][23][24] Au plates as typical 2D plasmonic nanomaterials are easily tuned and have a large range of applications in single-molecule optomechanics, plasmonic nanocavities, and dynamic Casimir optical cavities. [25][26][27][28][29] Most reaction systems require temperatures above 80 1C to obtain Au plates; [30][31][32] this work needs just 30 1C.…”

Plasmon-Mediated Hydrogen Dissociation with Symmetry Tunability

“…1−5 Localized surface plasmon resonance (LSPR) could occur in noble metal nanoparticles (NPs) and enhances light−matter interaction, which can greatly improve energy conversion efficiency. 6−8 The high catalytic activity of plasmonic metal has been attributed to (i) field enhancement (FE) owing to an elevated electric field near the nanostructure, 7,9,10 (ii) the transfer of electrons to foreign molecules by nonradiative plasmon decay, 5,11 and (iii) a localized thermal effect by plasmon decay. 12−14 For hot carrier-driven catalysis, hot electrons generated by plasmon decay can be transferred to the reactant through indirect electron transfer or direct electron excitation.…”

“…Plasmon-induced photocatalytic reactions have attracted considerable attention due to possible applications in solar energy conversions for solving the global energy crisis. − Localized surface plasmon resonance (LSPR) could occur in noble metal nanoparticles (NPs) and enhances light–matter interaction, which can greatly improve energy conversion efficiency. − The high catalytic activity of plasmonic metal has been attributed to (i) field enhancement (FE) owing to an elevated electric field near the nanostructure, ,, (ii) the transfer of electrons to foreign molecules by nonradiative plasmon decay, , and (iii) a localized thermal effect by plasmon decay. − For hot carrier-driven catalysis, hot electrons generated by plasmon decay can be transferred to the reactant through indirect electron transfer or direct electron excitation . The initially generated hot electrons undergo a thermalization process to form a thermal Fermi–Dirac distribution and then transfer into the adsorbed molecule, known as indirect electron transfer. , When a strong interaction exists between an adsorbent and plasmonic metal, a hybrid surface state is formed at the interface and provides an additional pathway for the direct generation of hot electrons in the adsorbent, known as direct charge transfer .…”