Tailoring the Surface Structures of CuPt and CuPtRu 1D Nanostructures by Coupling Coreduction with Galvanic Replacement

Abstract

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10. 1002/ppsc.201800053. 1D metal nanostructures exhibit unique properties due to their high aspect ratio for use in many applications including electrocatalysis. This work develops a solution-based approach to 1D multimetal nanostructures with tunable surface structures by combining the two processes of coreduction and galvanic replacement. In this approach, noble metals of Pt and Ru are reduced in the presence of in situ formed Cu seeds. At high concentrations of noble metal precursors, coreduction dominates over galvanic replacement, leading to overgrowth of ultrafine, particulate, or branched structures on the surface of the 1D nanostructures. The surface roughness and composition can be tuned by varying the concentrations of noble metal precursors. The electrochemical reactivity is not only affected by the surface roughness (i.e., the size of particulates and the level of branches) but also the surface composition (i.e., the amount of Pt content). For trimetallic nanostructures, the alloy composition prevents the dissolution of Ru thereby improving electrocatalytic stability of the catalyst under acidic conditions. The structure-property study reveals that the surface structure plays an important role in tailoring the electrocatalytic property of a catalyst.

Pt–Ni Seed-Core-Frame Hierarchical Nanostructures and Their Conversion to Nanoframes for Enhanced Methanol Electro-Oxidation

“…The open frame structures were more active catalysts than the solid nanoparticles for alcohol oxidations [16,35,36]. We demonstrated that other nanostructures with highly accessible surfaces including Pt-Cu nanodendrites [37], nanowires [38], core-frame and frame structures could enhance MOR activity [39]. In this work, we reported a seeded co-reduction method to synthesize the rhombic dodecahedral, hierarchical structure.…”

CuPt and CuPtRu Nanostructures for Ammonia Oxidation Reaction

“…The core-shell type nanostructures were synthesized using our previously-established, seed-mediated methods. [6][7][8] Briefly, Cu seeds were prepared by adding specific amounts of copper acetylacetonate (Cu(acac)2), copper chloride (CuCl2), and dodecylamine (DDA) to a 3-neck 25-mL round-bottom flask equipped with a temperature-controlled, heating mantle and a magnetic stirring plate. The flask was connected to a condenser for cooling and a Schlenk line to maintain air-free conditions.…”

Bimetallic Catalysts for Sustainable Chemistry: Surface Redox Reactions For Tuning The Catalytic Surface Composition

“…Other interesting approaches involving the galvanic replacement reaction were also studied as the synthesis of trimetallic nanomaterials [42][43][44][45] with controlled compositions by adjusting the molar ratio between the sacrificial templates and the metal modifier solutions introduced sequentially, or the coupling with co-reducing agents to provide a significant control over morphology for instance [39,46] . In the course of the galvanic replacement of Ag by Au in presence of ascorbic acid as co-reducing agent, Yang et al have observed that the freed Ag + ions are immediately reduced and deposited back onto the surface of the template leading to alloyed AgAu nanocages with more that 80 % of the initial Ag content retained in the walls [47] .…”