Reductive and Coordinative Effects of Hydrazine in Structural Transformations of Copper Hydroxide Nanoparticles.

Xenia Medvedeva,Aleksandra Vidyakina,Anna Klinkova,Feng Li,Andrey Mereshchenko

doi:10.3390/nano9101445

Xenia Medvedeva, Aleksandra Vidyakina + Show 3 more

Open Access

https://doi.org/10.3390/nano9101445

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Journal: Nanomaterials	Publication Date: Oct 11, 2019
Citations: 14	License type: CC BY 4.0

Affiliation: University of Waterloo, St Petersburg University

Abstract

Shape-specific copper oxide nanostructures have attracted increasing attention due to their widespread applications in energy conversion, sensing, and catalysis. Advancing our understanding of structure, composition, and surface chemistry transformations in shaped copper oxide nanomaterials during changes in copper oxidation state is instrumental from both applications and preparative nanochemistry standpoints. Here, we report the study of structural and compositional evolution of amorphous copper (II) hydroxide nanoparticles under hydrazine reduction conditions that resulted in the formation of crystalline Cu2O and composite Cu2O-N2H4 branched particles. The structure of the latter was influenced by the solvent medium. We showed that hydrazine, while being a common reducing agent in nanochemistry, can not only reduce the metal ions but also coordinate to them as a bidentate ligand and thereby integrate within the lattice of a particle. In addition to shape and composition transformation of individual particles, concurrent interparticle attachment and ensemble shape evolution were induced by depleting surface stabilization of individual nanoparticles. Not only does this study provide a facile synthetic method for several copper (I) oxide structures, it also demonstrates the complex behavior of a reducing agent with multidentate coordinating ability in nanoparticle synthesis.

Highlights

Controlled fabrication of copper oxides and hydroxides (e.g., CuO, Cu2O, CuOH, Cu(OH)2) nanostructures in different morphologies has attracted increasing attention in recent years due to their potential applications in energy conversion, electrode materials, sensing, and catalysis [1,2,3]
Multipod, branched, or dendric nanoparticles are of particular interest in conventional, electro, and photocatalysis due to their (a) highly developed surface area, (b) exposed high index facets and edges with undercoordinated sides, and (c) inability to densely pack on substrates, resulting in rough and porous material deposits, with all of these factors generally leading to higher catalytic activity [24,25]
Shaped copper oxide nanostructures are typically prepared by chemical reduction, electrodeposition, and solvothermal synthesis methods

Summary

Introduction

Controlled fabrication of copper oxides and hydroxides (e.g., CuO, Cu2O, CuOH, Cu(OH)2) nanostructures in different morphologies has attracted increasing attention in recent years due to their potential applications in energy conversion, electrode materials, sensing, and catalysis [1,2,3]. Various copper oxide materials have been used as precursors for oxide-derived copper for CO2 electroreduction [13,14,15] Maximization of their performance metrics in these processes relies on tailoring their structure, composition, and surface chemistry to optimize their physical and chemical properties that enable these applications. Does this study provide a facile and scalable method for several copper (I) oxide structures, but it demonstrates the complex behavior of a reducing agent with multidentate coordinating ability in nanoparticle synthesis

Materials

Electrochemical Reduction of Cu2O and Cu2O-N2H4

Nanoparticle Characterization

Synthesis of the Starting Material