Synthesis of new metastable nanoalloys of immiscible metals with a pulse laser technique

Abstract

The generation of nanoalloys of immiscible metals is still a challenge using conventional methods. However, because these materials are currently attracting much attention, alternative methods are needed. In this article, we demonstrate a simple but powerful strategy for the generation of a new metastable alloy of immiscible metals. Au1−xNix 3D structures with 56 at% of nickel in gold were successfully manufactured by the pulsed laser irradiation of colloidal nanoparticles. This technology can be used for preparing different metastable alloys of immiscible metals. We hypothesise that this technique leads to the formation of alloy particles through the agglomerations of nanoparticles, very fast heating, and fast cooling/solidification. Thus, we expect that our approach will be applicable to a wide range of inorganic solids, yielding even new metastable solids that fail to be stable in the bulk systems, and therefore do not exist in Nature.

Towards Atomically Precise Supported Catalysts from Monolayer‐Protected Clusters: The Critical Role of the Support

“…This is also supported by the shortened average Au−P/O bond length due to the contribution from the shorter Au−O bond (Tables and S1). The presence of the Au−Au bond peak at 3.4 Å, that is, at non‐bonding distances, for AuL/SiO 2 _120 and AuL/Carbon_60 shows that the Au‐phosphine complexes exist on the supports as ensembles, similar to isolated Au I ‐phosphine complexes that tend to form dimers/polymers due to aurophilic Au−Au interactions …”

Formation of metal/semiconductor Cu–Si composite nanostructures

“…The shell can be oxides, noble metals, phosphates or polymers [3,4]. Compositions of materials that are immiscible in the bulk state, such as Mo-Cu [5], Ag-Si [6], Ag-Cu [7], Au-Ni [8], are of special interest. Shells can have both a smooth spherical or a polyhedral shape, can have mesopores [9] or dendrites [10], or can even consist of three layers [11,12].…”

“…The structure of these nanoparticles is primarily determined by the methods and conditions of synthesis, which should allow us to combine the two materials even if they are immiscible in the bulk state. In addition to chemical techniques [9][10][11][12], physical methods such as gas-phase methods [5,6,15], laser ablation [7,8,16], and magnetron-sputter gas-phase condensation [17] have been developed. When these methods are combined with the possibility of rapid heating and evaporation of both materials and the possibility of rapid controlled cooling of the resulting vapour mixture, the formation of nanoparticles with a complex structure is possible.…”

Magnetically Assembled SERS Substrates Composed of Iron–Silver Nanoparticles Obtained by Laser Ablation in Liquid

“…The use of laser ablation in liquid is key to achieving bimetallic NPs in one step with ac lean surface availablef or functionalization with the desired thiolated molecules. [55] Similarly,i nteresting nanosystems werea lso obtained by laser irradiation of am ixture of NPs, such as solid solutionso fg old and nickel, [56,57] iron, [58] or cobalt. Allt hese characteristics were used for the magnetic assembly of plasmonic arrays which served as SERS substrates for the identification of molecules of analytical interest.…”

“…[52] Nanostructures with magnetic andp lasmonic responses obtained so far by this method include gold-iron [14,18,53,54] and silver-iron nanoalloys, [25] nanocrescents, [54] andc ore-shell structures with either ap lasmonic core and magnetic oxide shell [54] or am agnetic iron core and plasmonic shell. [55] Similarly,i nteresting nanosystems werea lso obtained by laser irradiation of am ixture of NPs, such as solid solutionso fg old and nickel, [56,57] iron, [58] or cobalt. [59] Herein, to achieve av ersatile nanomaterial endowed with magnetic and plasmonic properties, easy surfacec hemistry, and complete colloidal stability, as required for the realization of magnetically assembled and reusable SERS substrates, we synthesized iron-doped silver NPs by LAL.…”