Noble Metal-Based Nanocomposites

Preparation and Applications

Jun Yang

• Publisher: Wiley-VCH
• Year: 2019
• Print ISBN:
  9783527344529
• eBook ISBN:
  9783527814312
• Edition: 1
• Topic: Sciences physiques
• Subtopic: Chimie inorganique

Provides a systematic and coherent picture of the solution-based methods for the preparation of noble metal-based composite nanomaterials, their characterization, and potential applications in electrocatalysis

Within the last decade, the development of wet-chemistry methods has led to the blossom of research in composite nanomaterials. However, the design and synthesis of composite nanomaterials with controlled properties remains a significant challenge. This book summarizes the solution-based methods for the preparation of noble metal-based composite nanomaterials. It examines their characterization, as well as their use in electrocatalysis. It also discusses the intrinsic relationship between the catalytic properties and the physical /chemical effects in the composite materials, and offers some perspectives for the future development of metal-based composite nanomaterials. In addition, the book not only provides a systematic and coherent picture of this field, but also inspires rethinking of the current processing technologies.

Noble Metal-Based Nanocomposites: Preparation and Applications offers in-depth chapter coverage of ethanol-mediated phase transfer of metal ions and nanoparticles. It presents the full range of nanocomposites consisting of chalcogenide semiconductors and gold, silver sulfide, or other noble metals. It also examines core-shell structured cadmium selenide-platinum nanocomposites; Pt-containing Ag2S-noble metal nanocomposites for direct methanol fuel cells operated at high fuel concentrations; and nanocomposites consisting of metal oxides and noble metals. In addition, the book looks at scientific issues derived from noble metal-based nanocomposites.

-Covers all of the preparations of noble metal-based nanocomposites and their numerous applications
-Highlights some of the recent breakthroughs in the design, engineering, and applications of noble metal-based nanocomposites
-Appeals to a wide range audience, especially researchers in the areas of catalysis, chemistry, chemical engineering, materials synthesis and characterization, and fuel cell

Noble Metal-Based Nanocomposites: Preparation and Applications is an excellent book for inorganic chemists, materials scientists, catalytic chemists, chemical engineers, and those interested in the subject.

1
An Introduction to Noble Metal‐Based Composite Nanomaterials

1.1 Materials at Nanometer Scales

Materials including semiconductors, metals, and oxides at nanometer scales, in terms of nanomaterials, nanoparticles, or nanocrystals with controlled sizes/morphologies, have garnered a great deal of research interest due to their immense potential for various applications, e.g. catalysis and photonics [1–19]. Owing to the quantum confinement effect and/or the large surface‐to‐volume ratio, the physical and chemical properties of materials at nanometer scale are usually dependent on size and shape [4,512–1420–25]. One typical example to indicate the size influence on the chemical property of nanometer materials is the catalytic reduction of p‐nitrophenol to p‐aminophenol over gold (Au) nanoparticles stabilized by cetyltrimethyl ammonium bromide (CTAB) with average sizes in the range of 3.5–56 nm. The results suggest that the activity of the CTAB‐stabilized Au nanoparticles is neither very efficient for the smallest particles (3.5 nm) nor for the larger ones (28 and 56 nm). Instead, it turns out that the CTAB‐stabilized Au nanoparticles of an intermediate size (13 nm) are the most active ones for the catalytic reduction of p‐nitrophenol to p‐aminophenol [26]. In addition, for noble metal nanoparticles with different shapes, they could display different activities for the same catalytic reaction due to their different crystallographic surfaces [2,3,512–14,27,28]. In other words, noble metal nanoparticles with different shapes often display quite different catalytic behaviors [12,13]. For instance, Wang and coworkers demonstrated that the monodispersed Pt nanoparticles with controlled sizes of 3–7 nm and shapes of polyhedron, truncated cube, or cube are active catalysts for the oxygen reduction reaction (ORR) in acidic medium. However, the measured current density for 7‐nm Pt nanocubes is four times that of 3‐nm polyhedral (or 5‐nm truncated cubic) Pt nanoparticles, manifesting a significant effect of particle shape on the oxygen reduction [8].

We are currently witnessing the impressive successes in preparation of materials at nanometer scale. Over the past decades, a vast number of wet‐chemistry approaches, including the reduction of appropriate precursors in solution phases [1429–34], in microemulsions [35], or in sol–gel processes [36], have been developed to obtain various nanoparticles with well‐defined sizes and shapes. Further, the size/shape control of the nanoparticles could also be achieved through control of the nucleation and growth by varying the synthetic parameters, including the activity of the reducing agents, the type and concentration of the precursors, and the nature and amount of surfactants or protective reagents [3337–43]. As an important noble metal used in a wide variety of catalytic applications, single‐crystalline platinum (Pt) nanoparticles with diverse shapes, as summarized in Figure 1.1, have been synthesized in the presence of a capping agent through reducing a Pt precursor, decomposing an organometallic complex, or combining these two routes such as hydrogenated decomposition of platinum(II) acetylacetonate (Pt(acac)₂) [12].

Figure 1.1 Schematic illustration of different shapes of Pt nanocrystals derived from conventional single‐crystal polyhedrons enclosed by the low‐index planes {100} and {111}. The first column represents the perfect polyhedrons, while the second column contains the truncated forms of the perfect polyhedrons. The third and fourth columns compromise the overgrown nanostructures and highly branched nanostructures grown from the corners of the perfect polyhedrons, respectively. The yellow and blue colors represent the {100} and {111} facets, respectively.

Source: Chen et al. 2009 [12]. Adapted ...

Table of contents

• Cover
• Table of Contents
• About the Author
• Preface
• Acknowledgments
• List of Abbreviations
• 1 An Introduction to Noble Metal‐Based Composite Nanomaterials
• 2 Ethanol‐Mediated Phase Transfer of Metal Ions and Nanoparticles
• 3 Nanocomposites Consisting of Chalcogenide Semiconductors and Gold
• 4 Nanocomposites Consisting of Chalcogenide Semiconductors and Other Noble Metals
• 5 Nanocomposites Consisting of Silver Sulfide and Noble Metals
• 6 Nanocomposites Consisting of Chalcogenide Semiconductors and Noble Metals by Structural Transformations
• 7 Core–Shell‐Structured Cadmium Selenide–Platinum Nanocomposites
• 8 Pt‐Containing Ag2S–Noble Metal Nanocomposites for Direct Methanol Fuel Cells Operated at High Fuel Concentrations
• 9 Nanocomposites Consisting of Metal Oxides and Noble Metals
• 10 Scientific Issues Derived from Noble Metal‐Based Nanocomposites
• 11 Conclusion and Perspectives
• Index
• End User License Agreement