Shape-Controlled Metal Nanocrystals for Heterogeneous Catalysis

Abstract

The ability to control the shape of metal nanocrystals allows us to not only maneuver their physicochemical properties but also optimize their activity in a variety of applications. Heterogeneous catalysis, in particular, would benefit tremendously from the availability of metal nanocrystals with controlled shapes and well-defined facets or surface structures. The immediate benefits may include significant enhancements in catalytic activity and/or selectivity along with reductions in the materials cost. We provide a brief account of recent progress in the development of metal nanocrystals with controlled shapes and thereby enhanced catalytic performance for several reactions, including formic acid oxidation, oxygen reduction, and hydrogenation. In addition to monometallic nanocrystals, we also cover a bimetallic system, in which the two metals are formulated as alloyed, core-shell, or core-frame structures. We hope this article will provide further impetus for the development of next-generation heterogeneous catalysts essential to a broad range of applications.

Seed‐Mediated Growth of Colloidal Metal Nanocrystals

“…This can be accomplished by:1)bubbling an inert gas through the solutions prior to the reaction, [38] 2) adding ac apping agent, such as citric acid (CA) or citrate ion, capable of preventing O 2 adsorption, [39] or 3) scavenging O 2 in the solution with another redox pair (e.g.F e III /Fe II or Cu II / Cu I ). [41] [41] …”

Cubic Palladium Nanorattles with Solid Octahedron Gold Core for Catalysis and Alkaline Membrane Fuel Cell Applications

“…Noble metal nanostructures have attracted great attention in the arena of catalysis due to their stability and superior catalytic performance towards many chemical and electrochemical reactions . Metal nanoparticles of silver, gold, palladium, and platinum have been extensively explored because of their ease of synthesis which allows to manipulate their surface and optoelectronic properties by just tweaking their shape, size and morphology . In addition to monometallic nanoparticles, the array of bimetallic or trimetallic nanocatalysts has been significantly enriched in the last few decades .…”

“…In addition to monometallic nanoparticles, the array of bimetallic or trimetallic nanocatalysts has been significantly enriched in the last few decades . Latest reports of the synthesis, catalysis, structure and surface chemistry of bimetallic nanoparticles clearly indicate their importance in the field of heterogeneous catalysis . The arrangement of two or more metals, forming core‐shells, intermetallic alloys, metallic clusters, or heterometallic complexes, leads to alterations in the atomic as well as in the electronic structure of the nanoparticles and offers various benefits compared to monometallic nanocatalyst .…”

Facile Synthesis of Pd@Pt3–4L Core–Shell Octahedra with a Clean Surface and Thus Enhanced Activity toward Oxygen Reduction

“…To reduce the Pt loading in a PEMFC without compromising the performance, it is necessary to drastically enhance the activity of the Pt‐based catalyst. In general, the catalytic activity of a nanocrystal is highly dependent on its size, shape (e.g., the type of facets exposed), and surface electronic structure . To this end, a wide variety of Pt‐based mono‐ and bimetallic nanocrystals with controlled shapes have been synthesized to achieve improvement in activity toward ORR .…”