Role of Halide Ions for Controlling Morphology of Copper Nanocrystals in Aqueous Solution

Abstract

This paper reports the influence of halide ions on the morphology-controlled synthesis of Cu nanocrystals in the aqueous phase. Cu nanocrystals with controlled shapes, including 2D plates, 1D wires, and 3D polyhedral particles were obtained by a reduction reaction between Cu-halide and ascorbic acid, and branched polyethyleneimine (BPEI) was used as a stabilizing agent in the process. Density functional theory (DFT) calculations showed that this morphological control was caused by the selective adsorption of halide ions depending on the facets of the Cu nanocrystals. The thickness and lateral size of the Cu nanoplates were tuned easily using a co-stabilizer, the addition of Br À ions, and varying the pH of the reaction solution. Furthermore, the resulting Cu nanocrystals possessed great stability, showing very little change after exposure to the ambient atmosphere for 40 days. Overall, this synthetic procedure could be a potential method for the mass synthesis of morphology-controlled Cu nanocrystals for industrial applications because of the superior reaction conditions, such as the air atmosphere, low reaction temperature, water-phase-based synthetic condition as well as the use of nontoxic and inexpensive reagents.

Facile Aqueous-Phase Synthesis of Bimetallic (AgPt, AgPd, and CuPt) and Trimetallic (AgCuPt) Nanoparticles

“…Typically, because Cu can be easily oxidized by water and oxygen in the air, and its reduction potential is very different from the reduction potential of Pt or Ag, it is difficult to synthesize a Cu-based alloy compared with Ag-based alloy nanoparticles in an aqueous phase [25,26]. In a previous report on the aqueous-phase synthesis of Cu nanocrystals with long-term stability in air, it was demonstrated that BPEI formed a Cu-BPEI complex, thus leading to the formation of stable Cu nanocrystals in an aqueous phase [27,28]. In the present synthesis, we attempted to synthesize CuPt nanoparticles in We also investigated the synthesis of AgPd nanoparticles by using BPEI, L-ascorbic acid, AgNO 3 , and Na 2 PdCl 4 as similar synthetic conditions for AgPt nanoparticles.…”

Copper Template Design for the Synthesis of Bimetallic Copper–Rhodium Nanoshells through Galvanic Replacement

“…Also noteworthy, is that while most syntheses derive Cu 2+ from CuCl 2 as opposed to Cu(NO 3 ) 2 , its substitution into our reaction scheme yields unsatisfactory results in that only small protrusions grow off an otherwise spherical seed (Figure S2, Supporting Information). Chlorine ions are known to influence growth modes involving both Cu and CuO 2 . The resulting Cu templates, which are shaped as a substrate‐truncated cuboctahedrons, are highly faceted, displaying three prominent square (100) facets and four (111) facets.…”

Two-dimensional copper based colloidal nanocrystals: synthesis and applications

“…Tang et al demonstrated the influence of halide ions on the morphology-controlled synthesis of Cu nanocrystals in the aqueous phase. 88 The type of halide ion (Cl − , Br − , I − ) solely controlled the morphology of nanocrystals (2D plates, 1D wires, and 3D polyhedral particle). DFT study showed that the co-adsorption strength of ammonium and halide ions on Cu(100) compared to Cu(111) was a critical factor in regulating the shape of the Cu NCs.…”