A journey from bulk brass to nanobrass: A comprehensive study showing structural evolution of various Cu/Zn bimetallic nanophases from the vaporization of brass
Graphical abstract
Introduction
The distinct properties demonstrated by nanoscale materials demand intense scientific study to explore and utilize these materials for potential applications. Apart from the size and shape dependency, incorporation of a second component imparts synergistic effects and offers composition and structure controlled properties [1], [2], [3]. Copper-zinc based bimetallic chemistry is one of such systems of interest which has attained a lot of industrial attention owing to their catalytic applications especially in the fields of methanol production [4], [5], water gas shift reaction [6], [7], methanol steam reforming [8], [9] and hydrogenation reactions [10]. The alloy form of copper and zinc generally known as brass exhibits superior electrical and thermal conductivities, corrosion resistance, increased hardness and strength compared to pure copper [11]. In addition to well-known catalytic activities, copper alloys also exhibit antibacterial, antifungal, and optoelectronic properties leading to biomedical and electronic applications [12], [13].
Synthesis of CuZn alloy phases and intermetallic compounds have been realized using methods like wire electrical explosion [14], laser ablation [15], mechanical milling [16], and electric arc discharge [17]. Fischer et al. reported solution phase synthesis of CuZn nanoparticles via thermolysis of [Cu(OCH(Me)CH2NMe2)2] and Et2Zn in hot coordinating solvent hexadecyl amine [18] and co-hydrogenolysis of organometallic precursors [CpCu(PMe3)] and [ZnCp∗2] [19]. CuZn alloy has also been prepared by depositing Cu on epoxy substrate followed by electrochemical alloying with Zn by a reduction-diffusion method [20]. Solution synthesis of intermetallic γ-Cu5Zn8 was reported by Cable and Schaak by chemical conversion of Cu nanoparticles using zero valent organometallic zinc precursors [21]. Recently, selective synthesis of intermetallic nano-brass phases β-CuZn and γ-Cu3Zn were reported by microwave induced decomposition of Cu and Zn amidinate precursors [22]. The Cu/ZnO catalyst has been prepared by co-precipitation from mixed solutions of copper and zinc salts followed by ageing and calcination [23]. In addition, methods such as, selective photo deposition of Cu on ZnO nanoparticles [24], controlled thermolysis of Zn[Cu(CN)3] [25], aerosol assisted chemical vapor deposition of hetero metal complexes [26], and in situ impregnation of copper nanoparticles on ZnO nanorods [27] are some of the methods that have been used for the preparation of Cu/ZnO nanocomposites in various morphologies. Synthesis of Cu@ZnO core-shell nanocomposites of size 3.0 ± 0.7 nm was reported by us via digestive ripening process of Cu and Zn nanoparticles prepared individually by solvated metal atom dispersion (SMAD) process [28].
Solvated metal atom dispersion method of synthesis is a top down approach comprising of vaporization of a bulk material under vacuum. This is followed by the growth of clusters from atoms in low temperature matrices [29]. Using this method a variety of nanostructured materials have been realized [30], [31], [32], [33]. The advantages of SMAD process include easy scale up, high yield, and reproducibility. Since no side products are formed, tedious purification procedures are avoided. Additionally, this method holds great potential for the synthesis of reactive nanoparticles [34], [35]. In the backdrop of available literature as discussed above, we attempted to study the vaporization of bulk brass by the SMAD method. This is the first investigation of vaporization of an alloy by the SMAD method; earlier reports on the SMAD synthesis of nanoparticles included metals, metal chalcogenides, and metal halides. We further got motivated to study brass owing to several phases including metastable forms known in the Cu-Zn phase diagram. The copper-zinc phase diagram shown in Fig. 1 displays various phases known for brass as a function of temperature and composition [36]. Moreover, the nanoscale is characterized with structures like core-shell/composites apart from alloy and intermetallic phases. We observed dealloying of brass during controlled vaporization in SMAD method which upon nucleation and growth processes resulted in a metastable core shell structure, Cu/Zn@Cu with Zn core in a shell of Cu. We were able to transform these core-shell particles into brass nanoparticles going through a series of alloy/intermetallic/metastable phases. To the best of our knowledge, this is the first time a large number of nanostructures and phases have been observed in a single study starting from bulk brass. Herein, we report the structural and morphological evolution of various Cu/Zn bimetallic nanoparticles obtained under different experimental conditions, from the vaporization of bulk brass using the SMAD method.
Section snippets
Materials
Brass foil (0.51 mm thick, Johnson Matthey Chemicals India Pvt. Ltd), with Cu: Zn weight percentage 70:30 was used as the starting material for SMAD process. Tungsten crucible (R. D. Mathis Company, California) coated with alumina cement (Zircar Ceramics Inc, Florida) was used as a basket for placing the brass foil during the experiment. Tetrahydrofuran (S.D. Fine Chemicals Limited, India) and 4-tert-butyltoluene (Tokyo Chemical Industry Co., Ltd.) were dried over sodium–benzophenone.
Vaporization of brass foil and nanocomposite formation
Vaporization of brass alloy in a SMAD reactor resulted in dealloying of its components, Cu and Zn. In a typical SMAD experiment, the temperature of the crucible is increased in small steps until vaporization of the bulk material is completed. When brass foil was vaporized, we observed the appearance of a blue color on the initially formed white colored solvent matrix on the walls of the SMAD reactor. Vaporization was continued over a range of temperatures as indicated by the darkening of the
Conclusions
In summary, we demonstrated a structural evolution of various phases of Cu-Zn system starting from bulk brass. The dealloying of brass followed by in situ nucleation and growth produced core-shell nanocomposites, Cu/Zn@Cu in the solvated metal atom dispersion (SMAD) method. The use of hexadecyl amine as capping agent in SMAD synthesis drastically improved the colloidal stability as well as morphology of the nanocomposites. Heat treatments of Cu/Zn@Cu core-shell nanocomposites under different
Acknowledgements
We gratefully acknowledge the financial support from the Council of Scientific and Industrial Research, India (01/(2754)/13/EMR-II). S.P.B thanks the CSIR for a fellowship.
References (75)
- et al.
Synthesis and catalytic properties of bimetallic nanomaterials with various architectures
Nano Today
(2012) - et al.
Cu/ZnxAlyOz supported catalysts (ZnO: Al2O3 = 1, 2, 4) for methanol synthesis
Catal. Today
(2011) - et al.
The stability of Cu/ZnO-Based catalysts in methanol synthesis from a CO2-rich feed and from a CO-rich feed
Appl. Catal. A Gen.
(2001) - et al.
Effect of Cu loading on Cu/ZnO water-gas shift catalysts for shut-down/start-up operation
Int. J. Hydrogen Energy
(2012) - et al.
Water-gas shift reaction over Cu/ZnO and Cu/ZnO/Al2O3 catalysts prepared by homogeneous precipitation
Appl. Catal. A Gen.
(2006) - et al.
Microstructural characterization of Cu/ZnO/Al2O3 catalysts for methanol steam reforming—a comparative study
Appl. Catal. A Gen.
(2008) - et al.
Steam reforming of methanol using Cu-ZnO catalysts supported on nanoparticle alumina
Appl. Catal. B Environ.
(2008) - et al.
Georgeite and azurite as precursors in the preparation of Co-Precipitated copper/zinc oxide catalysts
Appl. Catal. A Gen.
(1992) - et al.
The antimicrobial activity of copper and copper alloys against nosocomial pathogens and Mycobacterium Tuberculosis isolated from healthcare facilities in the western cape: an in-vitro study
J. Hosp. Infect.
(2008) - et al.
Humidity sensing properties of KCl-doped Cu–Zn/CuO–ZnO nanoparticles
Sens. Actuat. B-Chem.
(2009)
Preparation and characterization of nanocrystalline powders of Cu–Zn alloy by wire electrical explosion method
Mater. Sci. Eng. A
Preparation of beta brass by mechanical alloying of elemental copper and zinc
Scr. Metall.
Single phase synthesis of γ-brass (Cu5Zn8) nanoparticles by electric arc discharge method and investigation of their order-disorder transition temperature
Intermetallics
Two step copper impregnated zinc oxide microball synthesis for the reduction of activation energy of methanol steam reformation
Chem. Eng. J.
Facile fabrication of nanoporous platinum by alloying–dealloying process and its application in glucose sensing
Sens. Actuat. B-Chem.
New preparation method of micron porous copper through physical vacuum dealloying of Cu–Zn alloys
Mater. Lett.
Recent developments in the Research of shape memory alloys
Intermetallics
Single crystalline β phase Cu–Zn nanowires: synthesis and martensitic transformation
Mater. Lett.
Synthesis, thermal evolution and optical properties of CuZn alloy nanoparticles in SiO2 sequentially implanted with dual ions
J. Alloy Compd.
Mechanism of mechanical alloying in Ni-A1 and Cu-Zn systems
Mater. Sci. Eng. A
Digestive ripening facilitated atomic diffusion at nanosize regime: case of AuIn2 and Ag3In intermetallic nanoparticles
J. Alloys Compd.
Role of Kirkendall effect in diffusion processes in solids
Trans. Nonferrous Met. Soc. China
Bimetallic nanoparticles-novel materials for chemical and physical applications
New J. Chem.
Nanoalloys: from theory to applications of alloy clusters and nanoparticles
Chem. Rev.
Molecular brass: Cu4Zn4, a ligand protected superatom cluster
Chem. Commun.
Production of copper and brass nanoparticles upon laser ablation in liquids
Quantum Electron.
Nano-brass: bimetallic copper/zinc colloids by a nonaqueous organometallic route using [Cu(OCH(Me)CH2NMe2)2] and Et2Zn as precursors
Chem. Mater.
Nano-brass colloids: synthesis by Co-Hydrogenolysis of [CpCu(PMe3)] with [ZnCp*2] and investigation of the oxidation behaviour of α/β-CuZn nanoparticles
J. Mater.Chem.
Potentiostatic Cu-Zn alloying for polymer metallization using medium-low temperature ionic liquid baths
J. Electrochem. Soc.
Solution synthesis of nanocrystalline M-Zn (m = Pd, Au, Cu) intermetallic compounds via chemical conversion of metal nanoparticle precursors
Chem. Mater.
Synthesis of Cu, Zn and Cu/Zn brass alloy nanoparticles from metal amidinate precursors in ionic liquids or propylene carbonate with relevance to methanol synthesis
Nanoscale
Co-precipitated copper zinc oxide catalysts for ambient temperature carbon monoxide oxidation: effect of precipitate ageing on catalyst activity
Phys. Chem. Chem. Phys.
Interfacial Cu/ZnO contact by selective photodeposition of copper onto the surface of small ZnO nanoparticles in non-aqueous colloidal solution
Phys.Chem. Chem. Phys.
A straightforward route to copper/zinc oxide nanocomposites: the controlled thermolysis of Zn[Cu(CN)3
Eur. J. Inorg. Chem.
Isostructural copper–zinc mixed metal complexes for single source deposition of Cu–ZnO composite thin films
Dalton Trans.
Synthesis of Cu@ZnO core-shell nanocomposite through digestive ripening of Cu and Zn nanoparticles
J. Phys. Chem. C
Introduction to metal atom syntheses
Inorg. Synth.
Cited by (21)
In situatomic-scale observation of the conversion behavior in a Cu-Zn alloy for twinnability enhancement
2022, Applied Surface ScienceCitation Excerpt :The diffusion direction was based on a concentration gradient of Cu and Zn. The formation of the final product, α phase, resulted from the high solubility, high interdiffusion coefficient, and negative mixing enthalpy when the temperature was increased to 300 ℃ [28,40]. In addition, the formation energy of the β phase was lower than that of the α phase [41].
Effect of [Zn<sup>2+</sup>]/[Cu<sup>2+</sup>] ratio of the bath on the composition and property of Cu–Zn alloy micropillars prepared using microanode-guided electroplating
2021, Electrochimica ActaCitation Excerpt :The lattice fringes measured from the HRTEM image shown in Fig. 5(b) indicate a d-spacing of 0.21 and 0.18 nm, which could be assigned to the (111) and (200) plane of α-brass, respectively. This d-spacing is in agreement with that reported in literature [38]. The corresponding selected area electron diffraction (SAED) depicted in Fig. 5(c) reveals that few continuous diffraction rings, identified as {111}, {200}, {220}, and {311} of α-brass with crystalline spots are presented.
Air-stable magnetic cobalt-iron (Co<inf>7</inf>Fe<inf>3</inf>) bimetallic alloy nanostructures via co-digestive ripening of cobalt and iron colloids
2020, Journal of Alloys and CompoundsCitation Excerpt :The temperature at which digestive ripening process is carried out, the choice of capping ligands and the metal-capping ligand interactions are very crucial to develop newer nanomaterials. We have been using the solvated metal atom dispersion in combination with digestive ripening to obtain diverse nanostructured materials such as Au [35], Ca [36], Cu@ZnO [37], Au@Ag [38], and Au@Pd core-shell [39], AuAg, AuCu [40], CuZn [41], AuIn2, Ag3In [42], and AuSn5 intermetallics [43]. Herein, we report the synthesis of Co7Fe3 alloy nanostructures using digestive ripening process.
Diffusional behaviors and mechanical properties of Cu–Zn system
2020, Journal of Alloys and CompoundsCitation Excerpt :Three regions in different colors represent three IMCs, although the thin β′ layer embedded between Cu_fcc and γ are difficult to be observed. It is noteworthy that, a recent study [16] assigned the stoichiometric ratio of CuZn5 to the ε phase, in contradiction with the previous result of CuZn4 [17]. Our experimental data shows the stoichiometric ratio of ε phase is more close to CuZn5, thus the ε phases denotes ε(CuZn5) in this work.
Leaded brass alloys for gamma-ray shielding applications
2019, Radiation Physics and ChemistryCitation Excerpt :For example, in a study it was reported that non-dezincification resistant brass alloy CuZn40Pb2 can be used in drinking water systems according to the parametric values given in the EU's Drinking Water Directive (Latva et al., 2017). Bimetalic brass (CuZn) and other brasses have been widely investigated in terms of mechanical and physical properties for potential applications (Latva et al., 2017; Küçükömeroğlu and Kara, 2014; Suárez et al., 2015; Yu Hung et al., 2016; Rotty et al., 2016; Bhaskar and Jagirdar, 2017; Schultheiss et al., 2017, Ramesh et al., 2018). Due to their potential use as a radiation shield, some studies were conducted in literature for estimating radiation shielding properties of bimetallic brass or other brass alloys.
Structural evolution and electronic properties of Cu-Zn alloy clusters
2019, Journal of Alloys and CompoundsCitation Excerpt :By now, a mixture of different phases of brass nanoparticles including α, β, γ and ε has been obtained by several fabrication methods [13–17]. Recently, Jagirdar et al. prepared Cu/Zn@Cu core-shell nanocomposites and demonstrated a structural evolution of various Cu-Zn bimetallic nanophases starting from bulk brass [15]. Although a number of experimental studies of bulk brass have been reported, there are little studies on brass alloys with the atomic-scale structures.