Pt/Ag Solid Solution Alloy Nanoparticles in Miscibility Gaps Synthesized by Cosputtering onto Liquid Polymers

Abstract

Pt/Ag solid solution alloy nanoparticles (NPs) with mean size below 3 nm were obtained with composition in miscibility gaps by cosputtering onto liquid polyethylene glycol (PEG, MW = 600). Adjusting the sputtering currents from 10 to 50 mA did not influence the particle sizes obviously but caused a substantial difference in the composition and distributions of Pt/Ag NPs. This is different from sputtered Pt/Au NPs where particle size is correlated with composition. For a pair of sputtering currents, the formed Pt/Ag alloy NPs have a range of compositions. The normal distribution with Pt of 60.2 ± 16.2 at % is observed for the Pt/Ag sample with a nominal Pt content of 55.9 at %, whereas Pt-rich (85.1 ± 14.0 at % Pt) and Ag-rich (19.8 ± 12.2 at % Pt) Pt/Ag samples with nominal Pt contents of 90.9 and 11.9 at % contain more pure Pt and pure Ag NPs, respectively. Different from NPs obtained in PEG, the sputtered NPs on TEM grids had more uniform composition for a longer sputtering time along with a significant increase of particle sizes. This reveals that PEG hindered the combination of NPs and clusters, resulting in small particle sizes even for long time sputtering and broader composition distributions. Thus, the samples obtained in PEG have the compositions mainly determined by the random atom combination in the vacuum chamber and possibly in initial landing of atom/clusters on the PEG surface.

Co-sputtered CuPt/Ag alloy nanoparticles and comparative catalytic performance of mono-, bi-, and tri-metallic nanoparticles in the oxygen reduction reaction

“…37 We successfully synthesized bimetallic Ag/Au, Cu/Au, Cu/Pd, Pt/Au, and Ag/Pt solid solution alloy NPs with a tunable composition by co-sputtering onto liquid polyethylene glycol (PEG) and varying the sputtering currents applied to metal targets. 13,36,38–41 Besides, we also shed light on the formation mechanism of alloy NPs. 13 Synthesis of trimetallic alloy NPs by sputtering onto a liquid has been reported by Cai et al 42 They prepared PdAu/Pt NPs by successively sputtering onto ionic liquid (IL) containing carbon nanotubes and applied PdAu/Pt on carbon nanotubes to the methanol oxidation reaction (MOR).…”

“…13,36,38–41 Besides, we also shed light on the formation mechanism of alloy NPs. 13 Synthesis of trimetallic alloy NPs by sputtering onto a liquid has been reported by Cai et al 42 They prepared PdAu/Pt NPs by successively sputtering onto ionic liquid (IL) containing carbon nanotubes and applied PdAu/Pt on carbon nanotubes to the methanol oxidation reaction (MOR). Pt-based NPs also showed good catalytic performance for other reactions.…”

Sputtering onto liquids: a critical review

“…They reported a rather small discrepancy between the composition of the NPs sputtered on ILs, probed by STEM-EDS, and the composition of the thin film sputtered under the same conditions and evaluated by mass measurements. Later, a similar research has been made for Pt/Ag NPs [ 261 ]. However, the dispersion in the composition of the NPs present in the solution is large (i.e., from 16 up to 70%) [ 261 ].…”

“…Later, a similar research has been made for Pt/Ag NPs [ 261 ]. However, the dispersion in the composition of the NPs present in the solution is large (i.e., from 16 up to 70%) [ 261 ]. Over the years, the co-SoL method has been successfully used to synthesize other bimetallic alloy NPs, such as Fe/Ni [ 135 ], or Fe/Al [ 200 ].…”

Anisotropic Growth of Copper Nanorods Mediated by Cl–Ions

“…Metallic fine particles have been intensively researched for several decades. − Among the metals available, copper (Cu) is of great interest because it is non-expensive, abundant, and non-toxic and has impressive properties such as good conductivity, good catalytic properties, and anti-electromigration. − Cu particles with different morphologies and sizes have been used in many industries. For example, Cu fine particles are widely applied in printing electronic fields − and Cu nanoparticles are broadly used as catalysts − while Cu nanowires are popular as transparent conducting electrode materials. − …”