General Synthesis of Large Inorganic Nanosheets via 2D Confined Assembly of Nanoparticles

Abstract

Assembling nanoparticles to spatially well-defined functional nanomaterials and sophisticated architectures has been an intriguing goal for scientists. However, maintaining a long-range order of assembly to create macrostructures remains a challenge, owing to the reliance on purely interparticle interactions. Here, we present a general strategy to synthesize a class of inorganic nanosheets via a bottom-up directional freezing method. We demonstrate that, by confining a homogeneously dispersed metal-cyano colloidal suspension at the ice–water interface, followed by removal of ice crystals, large nanosheets with a lateral scale of up to several millimeters can be produced. The formation of millimeter-sized nanosheets is attributed to balanced electrostatic forces between dispersed nanoparticles, coupled with an appropriate hydrodynamic size of nanoparticles, potentially favorable lattice matching between nanoparticles and ice crystals, and the intermediate water at the ice–particle interface. The highly anisotropic growth of ice crystals can therefore guide the 2D confined assembly of nanoparticles in a long-range order, leading to well-defined 2D nanosheets. This contribution sheds light on the potential of nanoparticle assembly at larger length scales in designing families of large 2D nanoarchitectures for practical applications.

Atomically Reconstructed Palladium Metallene by Intercalation-Induced Lattice Expansion and Amorphization for Highly Efficient Electrocatalysis

“…Regulating the morphology of electrocatalysts at nanoscale is a typical strategy to boost their catalytic activity . Among them, two-dimensional (2D) morphology demonstrates distinctive electronic, photonic, and surface properties, which substantially enhances its catalytic performance. − As a class of 2D nanomaterials, metallenes are characterized by metallic compositions with atomic thickness and a curved surface, which deliver a distinctive surface–interface effect and ultrahigh atomic utilization originating from the graphene-like 2D structure, exhibiting great potential in electrocatalytic reactions for energy conversion . Most recently, Pd-based metallenes with various metallic dopants have been reported and achieved ORR activity comparable to that of Pt-based catalysts. ,− In addition to altering the morphology, tuning the lattice strain of Pd can further improve its catalytic activity by optimizing the activation energy barrier of the reactants and the adsorption behavior of intermediates during the catalytic process .…”

Pore Engineering for High Performance Porous Materials

“…In addition to using pre-existing hard-templates, the templates can also be generated in situ . Guihua Yu’s team reported the preparation of porous materials through a strategy called “freezing” of nanoparticle solutions . During the preparation process, the gradually forming ice crystals confines the assembly of nanoparticles in the 2D space between the ice crystals, resulting in the formation of numerous 2D layered structures.…”

Recent advances in nanoarchitectures of monocrystalline coordination polymers through confined assembly

“…The crack propagation and periodicity could be tailored by controlling the evaporation front and the withdrawal speed, making photonic sensors possible. To pack the coordination polymer particles denser, stronger forces were introduced by casting the particle dispersion at an ice–water interface [ 142 ]. After freezing of the residual water, the particles were squeezed by ice in a 2D space, forming nanosheets.…”