Syntheses and Properties of Metal Nanomaterials with Novel Crystal Phases

Abstract

In recent decades, researchers have devoted tremendous effort into the rational design and controlled synthesis of metal nanomaterials with well-defined size, morphology, composition, and structure, and great achievements have been reached. However, the crystal-phase engineering of metal nanomaterials still remains a big challenge. Recent research has revealed that the crystal phase of metal nanomaterials can significantly alter their properties, arising from the distinct atomic arrangement and modified electronic structure. Until now, it has been relatively uncommon to synthesize metal nanomaterials with novel crystal phases in spite of the fact that these nanostructures would be promising for various applications. Here, the research progress regarding the fine control of noble metal (Au, Ag, Ru, Rh, Pd) and non-noble metal (Fe, Co, Ni) nanomaterials with novel crystal phases is reviewed. First, synthesis strategies and their phase transformations are summarized, while highlighting the peculiar characteristics of each element. The phase-dependent properties are then discussed by providing representative examples. Finally, the challenges and perspectives in this emerging field are proposed.

Confined Synthesis of 2D Nanostructured Materials toward Electrocatalysis

“…could also be explored by reasonably selecting the reaction precursors and layered materials. In particular, if 2D nanomaterials with unusual crystal phases144–148 or amorphous structures,149–151 and crystal‐phase heterostructures152–155 or amorphous/crystalline hetero‐phase nanostructures156,157 can be prepared via confined synthesis, their promising properties and applications can be explored, which is an important research direction in the near future. Moreover, other host matrices, such as black phosphorus,158,159 hexagonal boron nitride,160,161 graphitic carbon nitride,162,163 silicene,164,165 antimonene,166,167 2D perovskites,168,169 as well as 2D MOFs and COFs, could be developed as new nanoreactors.…”

Structural‐Phase Catalytic Redox Reactions in Energy and Environmental Applications

“…Each of these techniques has its own merits and potential in changing the phase from one to another. Nevertheless, to date, the transition metal dichalcogenides (TMDs), noble metals (e.g., Pt, Rh, Ag, Au, Ir, and Ru), SnS 2 , SnS, GaAs, and InAs, have been reported to exhibit different phases . Generally, most of the pure metals in the periodic table may adopt one of the three possible structures: fcc, hcp, or bcc structures.…”

Observation of Non‐FCC Copper in Alkynyl‐Protected Cu53Nanoclusters

“…The crystal phase of a metal is fundamentally related to its various properties, such as magnetism, stability, optical properties, and catalytic behavior . Modulation of the metal crystal structure to exploit novel physicochemical property and functionality is thus becoming an active research subject . Different metals have strong preference for lattice type.…”

“…For example, among the two regular lattices that achieve the highest packing density, the coinage metals Au, Ag, and Cu mostly crystallize in face‐centered cubic (FCC) rather than hexagonal close‐packed (HCP) structure, since the former is more thermodynamically stable . Recent efforts from both physicists and chemists, however, have provided practical techniques to fabricate non‐FCC Au and Ag, including physical vapor deposition, seed or template mediated growth, electrodeposition, and high‐pressure‐induced phase transformation . Another strategy related to the work here is solution phase synthesis of metal nanoclusters (NCs) stabilized by organic ligands.…”