Volume 2, Issue 5 - Special issue: Nanocatalysis \ Issue editor: Ning Yan

Bimetallic nanostructures with well-defined shapes have shown distinct and advantageous catalytic properties compared to their monometallic counterparts. The use of bimetallic electrocatalysts may improve activity and durability, in addition to the possibility of reducing the loading of precious metals. A variety of bimetallic nanocrystals with different shapes has been reported in recent years. Their activities toward electrochemical catalytic reactions such as oxygen reduction and alcohol oxidations have been intensively studied. In this review, we discuss some latest developments in the morphology-controlled synthesis of Pt- and Pd-based bimetallic nanocrystals with shapes such as nanodendrites, polyhedra, porous hollow structures, and core shells, as well as their applications as electrochemical catalysts.

In the past few decades, metal nanoparticles applied in heterogeneous catalysis have attracted extensive attention. The term nanocatalysis is broadly referred to as the unique catalytic effect of this series of materials. Although considerable progress has been made in nanocatalysis, it still remains a great challenge to fully understand the nature of active sites in the nanoscale. Many concepts and models have been put forwarded to describe the properties and performances of nano- and subnanoparticles in catalysis. In this review, we propose our perspective on the active sites of heterogeneous catalysis from the aspects of electronic structure and geometric structure of nanoclusters and consider briefly how these clusters function in catalysis. The challenge in nanocatalysis research methods is also discussed.

Gold nanoparticles have been demonstrated to be efficient catalysts for a wide range of reactions in the past decades, such as oxidation and hydrogenation. In recent research, gold nanoparticle catalysts have been utilized in carbon-carbon coupling reactions. These coupling reactions have been established as convenient and general approaches toward biaryl or propargylamines, which are biologically active compounds, natural products, and pharmaceutical organic compounds. This review aims to highlight the current achievements in the field of gold nanoparticle-catalyzed coupling reactions, including Ullmann homocoupling of halides, oxidative homocoupling of organoboronates, Suzuki cross-coupling of phenylboronic acid and halides, Sonogashira cross-coupling of iodobenzene and phenylacetylene, and A 3 -coupling reaction of phenylacetylene, amines, and aryl or alkyl aldehydes. The catalytic mechanisms of these carbon-carbon coupling reactions are discussed. Finally, we provide our perspectives on some future work on gold nanocatalysis in coupling reactions.

One key goal of heterogeneous catalysis study is to understand the correlation between the catalyst structure and its corresponding catalytic activity. In this review, we focus on recent strategies to synthesize well-defined Fischer-Tropsch synthesis (FTS) nanostructured catalysts and their catalytic performance in FTS. The development of those promising catalysts highlights the potentials of nanostructured materials to unravel the complex and dynamic reaction mechanism, particularly under the in situ reaction conditions. The crucial factors associated with the catalyst compositions and structures and their effects on the FTS activities are discussed with an emphasis on the role of theoretical modeling and experimental results.

Ionic liquids (ILs) are well established as solvents and stabilizing agents for the synthesis of metallic nanoparticles (NPs) in general. The physicochemical properties of ILs and the supramolecular organization in the liquid state are capable of directing the growth of transition metal NPs generated in situ and to subsequently protect and stabilize them. Until now, many different NPs have been successfully synthesized within these media; however, the synthesis of metal oxide and bimetallic alloy or core-shell NPs in ILs is still relatively rare. Herein, we summarize the current state-of-the-art of the synthetic methods for these materials and their application in the broad field of catalysis, including multiphase systems, hydrogenation, dehydrogenation, functionalization, as well as defunctionalization reactions.

This review is focused on metal nanoparticles (NPs) supported on magnetic responsive solids and their recent applications as magnetically recoverable nanocatalysts. Magnetic separation is a powerful tool for the fast separation of catalysts from reaction medium and an alternative to time-, solvent-, and energy-consuming separation procedures. Metal NPs attached to a magnetic solid can be easily carried and recovered by magnetic separation. Some examples of magnetically recoverable metal NPs used in hydrogenation, oxidation, C-C coupling reactions, photocatalysis, and other organic reactions will be given.