Enhancing Galvanic Replacement in Plasmonic Hollow Nanoparticles: Understanding the Role of the Speciation of Metal Ion Precursors

Abstract

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.

Template-assisted synthesis of Ag/AgCl hollow microcubes and their composition-dependent photocatalytic activity for the degradation of phenol

“…[11][12][13] It is well known that hollow structures are believed to further improve the catalytic performance of plasmonic photocatalysts thanks to the accessible surface and interior cavity, efficient light collection, shortened distance for carrier transfer and separation, rich surface reaction sites on the shells, and a uniform distribution of metal nanoparticles. [14][15][16] Furthermore, hollow semiconductors are lighter than the corresponding solid structure, and benet the homogeneous dispersion in the reaction system of photocatalysis. As for hollow plasmonic photocatalysts, the powerful surface plasmonic resonance absorption and intracavity multiple reections of visible light can improve the total absorption efficiency of photon energies.…”

Review on Theoretical Models of Void Evolution in Crystalline Particles

“…Determined by high specific area and surface-tovolume ratio, low density and encapsulate option, hollow structures exhibit higher performance than their solid counterparts with the same composition and size that tremendously extends their application in the fields of plasmonics [3][4][5], catalysis [6][7][8][9][10][11], energy storing [12][13][14][15] and medicine [16][17][18]. For instance, hollow metal nanoparticles have significantly higher plasmonic properties than their solid counterparts due to so-called mechanism of plasmon hybridization.…”

Post-synthesis heating, a key step to tune the LPR band of gold nanorods covered with CTAB or embedded in a silica shell

“…As well known, metallic nanoparticles (MNPs), with a size smaller than the wavelength of the incident radiation, show resonance phenomena with the electro-magnetic field collectively called localized surface plasmon resonance (LSPR) [3][4][5][6]. LSPR properties are extremely interesting because they depend on, and consequently can be controlled by, the nature of the metal, the size and shape of the nanoparticles as well as the environment in which they are collocated [7][8][9][10][11][12][13][14][15][16]. In this way, an accurate synthetic method capable of controlling both the size and shape of the MNPs can allow tuning nanoparticle plasmonic properties [17,18].…”