Lattice Mismatch–Induced Formation of Copper Nanoplates with Embedded Ultrasmall Platinum or Palladium Cores for Tunable Optical Properties

Abstract

Although noble metal nanocrystals have been studied extensively in the past decades, the shape‐controlled synthesis of non‐noble metal nanocrystals has remained challenging with limited success, which is a grand obstacle to their wide applications. Herein, a novel lattice mismatch–involved shape‐control mechanism of Cu nanocrystals in a seed‐mediated synthesis is reported, which can produce Cu nanoplates in high yield with tailored sizes (28–130 nm), holding great potential in optical and catalytic applications. The lattice mismatch between Cu and the seed is found effective in inducing crystallographic defects for symmetry breaking toward anisotropic nanocrystals. While a too‐large lattice mismatch (11.7% for Au seeds) leads to multiple twin defects to form quasi‐spherical Cu nanocrystals, an appropriately large lattice mismatch (7.7% for Pt and 6.9% for Pd seeds) successfully induces planar defects for the formation of Cu nanoplates. The size of the Cu nanoplates is customizable by controlling the concentration of the seeds, leading to tunable optical properties. A prototype of a colorimetric indicator with Cu nanoplates, potentially applicable to the safety control of foods and drugs is demonstrated. This mechanism paves a new way for the shape‐controlled synthesis of Cu and other metal nanocrystals for a broad range of applications.

Advances in Strain‐Induced Noble Metal Nanohybrids for Electro‐Catalysis: From Theoretical Mechanisms to Practical Use

“…The choice of phase through lattice mismatch indices allows for the preparation of Cu surfaces with planar defects of different outer shapes, as well as the adjustment of surface layer sizes through the content of seeds such as Pd, forming structures like plates that are significantly larger than the core (Figure 1a). [14e] Moreover, in terms of controlling the shell thickness, Feng and colleagues successfully obtained Au@Rh(OH) 3 core‐shell structures with varying shell thicknesses through the thiol ligand‐mediated interfacial energy [10] . In fact, ligands selectively adsorb on specific facets of noble metal nanocrystals, leading to facet‐dependent rates of crystal growth, [23e] which has given rise to the preparation of various 2D materials that affect the surface noble metals as substrates [35] .…”

“…In addition to ligand assistance, the driving force of temperature is crucial. Hydrothermal reaction is a commonly used method for stable temperature control, which is capable of achieving metal overlayer coating under different lattice mismatch conditions [14e] . Post hydrothermal structuring control and subsequent reduction reactions, irregular particle cores of β ‐Ni(OH) 2 with unique flower‐like morphology can also complete the doping of Rh in β ‐Ni(OH) 2 through seed‐mediated growth [37] …”

Preventing the Galvanic Replacement Reaction toward Unconventional Bimetallic Core–Shell Nanostructures

“…The optical properties of Ag and Cu are closely related to their size, morphology, and surface properties [3,[63][64][65][66], which provides the possibility for the regulation of their optical properties by coating a noble metal layer and building core-shell nanostructures. Our group and Yan's group found that the localized surface plasmon resonance (LSPR) of Ag@Au core-shell nanocrystals had a red shift and an increasing intensity compared to Ag nanocrystals (Figure 9a,b) [35,62].…”

“…Bimetallic nanocrystals are receiving increasing interest in optics [1][2][3], catalysis [4][5][6][7][8][9][10], and many other fields [11][12][13][14][15]. For example, bimetallic nanocrystals are an excellent class of catalysts for many industrial processes and energy conversion thanks to their intriguing catalytic properties arising from the electronic and geometric interactions between constituent metals [8][9][10].…”

“…Among the different types of bimetallic nanocrystals, core-shell structured nanocrystals have attracted significant attention in recent years [1,[15][16][17][18]. These core-shell nanostructures may show many advantages, including convenient shape and facet control [3,6,19], the high utilization efficiency of the shell metals [17,20,21], and well-controlled properties due to the core-shell interactions [9,19,22,23].…”