Shaping Nanostructures for Applications in Energy Conversion and Storage

Authors

  • Prof. Dr. Hong Yang,

    Corresponding author
    1. Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana–Champaign, 114 Roger Adams Laboratory, 600 South Mathews Avenue, Urbana, IL 61801 (USA)
    • Hong Yang, Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana–Champaign, 114 Roger Adams Laboratory, 600 South Mathews Avenue, Urbana, IL 61801 (USA)

      Yadong Yin, Department of Chemistry, University of California Riverside, 900 University Ave., Riverside, CA, 92521 (USA)

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  • Prof. Dr. Yadong Yin

    Corresponding author
    1. Department of Chemistry, University of California Riverside, 900 University Ave., Riverside, CA, 92521 (USA)
    • Hong Yang, Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana–Champaign, 114 Roger Adams Laboratory, 600 South Mathews Avenue, Urbana, IL 61801 (USA)

      Yadong Yin, Department of Chemistry, University of California Riverside, 900 University Ave., Riverside, CA, 92521 (USA)

    Search for more papers by this author

Abstract

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In great shape: The conversion and storage of energy based on abundant natural resources such as water play an important role in the development of sustainable technologies. Such processes often depend on the use of catalysts that allow chemical and electrochemical reactions to occur effectively. This thematic issue aims to inspire further development of innovative approaches and well-defined nanomaterials for energy and sustainability applications.

The conversion and storage of energy based on abundant natural resources such as water play an important role in the development of sustainable technologies. Such processes often depend on the use of catalysts that allow chemical and electrochemical reactions to occur effectively. The design of shape-controlled nanomaterials helps in the manufacture of structures required for improved performance in catalysis.

This thematic issue is a collection of papers emphasizing the various effects of the shape and morphology of nanostructures made of metal, metal alloy, and other selected materials on catalytic and electronic properties. Not surprisingly, a sizable portion of the work presented in this issue deals with metal and metal alloy nanoparticles that are catalytically or electrocatalytically active. In this context, this body of work can be classified into three categories: metal and metal alloys, oxygen-containing compounds, and others (graphene, nitride, and II–VI semiconducting materials).

Zaera gives an overview on the effect of shape on the catalytic activity of nanoparticles. Among the several essential topics included in this Review, distinction between the effects of size and shape is described. Fukuzumi and Yamada further highlight recent results on nanomaterials with different shapes used in light harvesting, charge separation, and water oxidation and reduction by artificial photosynthesis. Shape-controlled metal nanoparticles are shown to be effective catalysts for both hydrogen and oxygen evolution reactions from water. On the recent development of single-metal nanostructures, the Xia group presents the synthesis of large icosahedral Pd nanoparticles (up to 35 nm) with >94% purity. These {111}-facet-dominant metallic structures display high catalytic activity towards formic acid oxidation. The Tsung group presents an alternative approach to the synthesis of icosahedral Pd nanoparticle catalysts, which are studied for the hydrogenation of ethylene. Beyond the platonic shapes, Skrabalak et al. present concave nanostructures of Au, including the overgrown trisoctahedral nanoparticles; and the Wang group describes concave Pd polyhedral structures with 32 facets obtained by selective etching with iodide ions. Electrocatalysts made of such Pd polyhedral structures show a dramatically enhanced specific activity towards the oxidation of ethanol, a molecule that is considered for application in low-temperature fuel cell. Besides these new morphologies, the Offin group demonstrates the use of a high-throughput method for screening new Pt- and Pd-based nanoparticles for oxygen reduction catalysts; while Huang and co-workers present the stable and regenerable Pt nanocrystal catalysts in aligned mesoporous silica. Sun et al. discuss the preparation of nanoframes of Ag and AgI composite based on the Kirkendall effect and controlled anion-exchange reaction with iodide ions. These hollow structures are studied for photocatalytic production of hydrogen from water.

Nanoparticles of bi- and multimetallic nanostructures are already viewed as important classes of catalysts for various energy conversion and storage applications, such as the electrochemical oxygen reduction reaction (ORR) for hydrogen fuel cells and lithium–air batteries. Two- or multiple-metal systems also lead to the ligand effect, that is, the enhanced catalytic activities that result from altering the d-electronic states. Shape (or facet) control is of particular importance in bettering the activity, durability, and selectivity of the reactions. Fang and Wang review the growth kinetics and electrocatalytic performance towards ORR of well-defined octahedral noble-metal nanostructures of various types. Yu and co-workers present a facile synthesis of PdCu nanocubes and their application as ORR catalysts. Chen et al. demonstrate the preparation of Pt–Cu dendrite structures and the CO resistance of such catalysts in catalytic oxidation of methanol. Hutchings and co-workers show that Au–Pd nanoparticles are better catalysts for the oxidation of 1-4-butanediol and butyrolactone than their single-metal counterparts.

Increasing the structural complexity of alloyed nanostructures is often necessary to further enhance the performance. In this regard, Yang et al. show that {111}-facet-dominant octahedral trimetallic Pt3Ni@Pt3Pd core–shell nanostructures can be prepared by a simple solution approach using CO gas. Such alloy@alloy octahedral catalysts combine both high activity and durability in a single electrocatalytic system. Song et al. present Au@Pd core–shell nanobricks with concave structures, which are highly active towards the electrochemical oxidation of ethanol in alkaline solutions due to both the synergistic effect of alloying and the exposed stepped surfaces and high-index facets. Interestingly, Au@Pd core–shell nanostructures are shown by Tilley et al. to be more active towards the catalytic conversion of glycerol and 1,2-propanediol than either Au or Pd nanoparticles. Besides core–shell nanostructures, Jin and co-workers show that Au–Cu meatball-like cages are beneficial for the oxidation of carbon monoxide at low temperatures, while Huang and colleagues report that nanostructured Au alloyed to porous Pd achieves a 95% conversion with 90% selectivity in the catalytic oxidation of benzyl alcohol.

A series of six papers is presented as a showcase of oxygen-containing compounds and their electronic and catalytic properties. Dai et al. review the catalytic applications of shape-controlled ceria-based catalysts. The correlation between surface and coordinated unsaturated sites and defect structure is discussed. Yin et al. show that sulfated ZrO2 hollow nanostructures can be used as superacids for the dehydration of fructose to 5-hydroxymethylfurfural. Zhang and co-workers describe the optical properties of shaped hematite nanoparticles. Huang and colleagues present surfactant-free cubic and octahedral Cu2O nanoparticles. The chemisorption and oxidation of CO on the surface of Cu2O are closely related to the surface composition. Xi and co-workers show {001}-surface oriented Bi2WO6 nanosheets, and conclude that the enhanced photocatalytic properties are due to a specific orientation of the sheets. Teng and colleagues show that octahedral nanoparticles of haumannite (Mn3O4) exhibit a high mass-specific capacitance. The reversible conversion between tetrahedral Mn2+ and octahedral Mn3+ sites is attributed to the enhanced redox stability.

Finally, Li et al. show that TiN nanotubes can be generated from nanoparticles and further covered by carbon uniformly. This non-Pt-based nanostructure shows excellent electrocatalytic activity for the ORR. The Yu group demonstrates that copper-modified ZnxCd1−xS quantum dots are seven times more active towards photocatalytic production of hydrogen from water than the pure ternary ones. Finally, Zhao and co-workers develop complex core–shell nanostructures made of graphitic carbons with an ordered microporous core and uniform mesoporous shell. This hierarchically ordered carbon material offers a high Li+ storage capacity, high rate, and a long cycling life.

Clearly, the papers presented in this thematic issue only represent a small portion of recent work in the fast-growing field of size- and shape-controlled nanomaterials for energy applications. As its guest editors, we are honored to be part of the effort to put together this thematic issue and sincerely wish that the work presented in this issue will inspire further development of innovative approaches and well-defined nanomaterials for energy and sustainability applications.

Biographical Information

Professor Hong Yang received his Ph.D. in Inorganic Chemistry from the University of Toronto (Canada) in 1998. He went to Harvard University (USA) and worked as an NSERC post-doctoral fellow from 1998 to 2001. He started his independent research at University of Rochester (USA) and went through the academic ranks before joining the faculty of the University of Illinois at Urbana–Champaign (USA) as a Professor of Chemical and Biomolecular Engineering in January 2012. Professor Yang is an NSERC Canada Doctoral Prize winner and an NSF CAREER Award recipient. His research interests include shape control of nanocrystals, surface modification, electrocatalysts, and nanomaterials for energy and biological applications.

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Biographical Information

Professor Yadong Yin received his Ph.D. in Materials Science and Engineering from the University of Washington (USA) in 2002, then worked as a post-doctoral fellow at the University of California, Berkeley and the Lawrence Berkeley National Laboratory (USA), and became a staff scientist at LBNL in 2005. In 2006 he joined the faculty at the Department of Chemistry at the University of California, Riverside (USA). His research interests include the synthesis of nanostructured materials and their catalytic, electronic, and photonic applications, self-assembly processes, and colloidal and interface chemistry.

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