Uniform size of Si nanowires (NWs) is highly desirable to enhance the performance of Si NW-based lithium-ion batteries. To achieve a narrow size distribution of Si NWs, the formation of bulk-like Si structures such as islands and chunks needs to be inhibited during nucleation and growth of Si NWs. We developed a simple approach to control the nucleation of Si NWs interfacial energy tuning between metal catalysts and substrates by introducing a conductive diffusion barrier.
View Article and Find Full Text PDFNanomaterials (Basel)
August 2021
Recent advances in nanoscience have opened ways of recycling substrates for nanomaterial growth. Novel materials, such as atomically thin materials, are highly desirable for the recycling substrates. In this work, we report recycling of monolayer graphene as a growth template for synthesis of single crystalline ZnO nanowires.
View Article and Find Full Text PDFHierarchical architectures composed of nanomaterials in different forms are essential to improve the performance of lithium-ion battery (LIB) anodes. Here, we systematically studied the effects of hierarchical ZnO nanostructures on the electrochemical performance of LIBs. ZnO nanowire (NW) trunks were decorated with ZnO NWs or ZnO nanosheets (NSs) by successive hydrothermal synthesis to create hierarchical three-dimensional nanostructures.
View Article and Find Full Text PDFSi/Ge core/shell nanowire heterostructures have been expected to provide high energy and power densities for lithium ion battery anodes due to the large capacity of Si and the high electrical and ionic conductivities of Ge. Although the battery anode performances of Si/Ge core/shell nanowire heterostructures have been characterized, the degradation of Si/Ge core/shell nanowire heterostructures has not been thoroughly investigated. Here we report the compositional and structural changes of the Si/Ge core/shell nanowire heterostructure over cycling of lithiation and delithiation at different charging rates.
View Article and Find Full Text PDFWe report on strain-induced structural defect formation in core Si nanowires of a Si/Ge core/shell nanowire heterostructure and the influence of the structural defects on the electrochemical performances in lithium-ion battery anodes based on Si/Ge core/shell nanowire heterostructures. The induced structural defects consisting of stacking faults and dislocations in the core Si nanowire were observed for the first time. The generation of stacking faults in the Si/Ge core/shell nanowire heterostructure is observed to prefer settling in either only the Ge shell region or in both the Ge shell and Si core regions and is associated with the increase of the shell volume fraction.
View Article and Find Full Text PDFPolyoxometalates (POMs), as inorganic ligands, can endow metal nanocrystals (NCs) with unique reactivities on account of their characteristic redox properties. In the present work, we present a facile POM-mediated one-pot aqueous synthesis method for the production of single-crystalline Pd NCs with controlled shapes and sizes. The POMs could function as both reducing and stabilizing agents in the formation of NCs, and thus gave a fine control over the nucleation and growth kinetics of NCs.
View Article and Find Full Text PDFIn this work we describe three different trends of pore growth for anodic aluminum oxide nanopores based on their dependence on prepatterned interpore distances. Nanopatterned hexagonal concave arrays were formed by focused ion beam (FIB) lithography on aluminum foil with interpore distances in the range of 100 to 240 nm and the Al foil was anodized under the standard conditions known to result in a 100 nm interpore distance. This method allowed a systematic investigation of pore formation under the non-equilibrium conditions created by the FIB prepatterning.
View Article and Find Full Text PDFAu-Pd alloy nanocrystals (NCs) with a hexoctahedral structure, enclosed exclusively by high-index {541} facets, are prepared via the simultaneous reduction of Au and Pd precursors without added seeds or additional metal ions as structure-regulating agents. Manipulating the NC growth kinetics via control of the relative amount of reductant is the key synthetic lever for controlling the morphology of the Au-Pd NCs. The hexoctahedral Au-Pd NCs exhibit higher catalytic performance toward the electro-oxidation of ethanol than low-index-faceted Au-Pd NCs.
View Article and Find Full Text PDFPlasmonic nanostructures with tunable optical properties and their designed spatial arrangements can facilitate a variety of application ranging from plasmonics to biosensors with unprecedented sensitivity. Here we describe a facile and versatile method for fabricating tunable plasmonic substrates based on the reshaping of metal nanocrystals. Anisotropic etching and redeposition of Ag atoms mediated by halide ions transformed Ag nanoprisms deposited on two- or three-dimensional surfaces or in solution into nanostructures with an oblate spheroidal shape, and corresponding localized surface plasmon resonances features could be tuned.
View Article and Find Full Text PDFHex appeal! Cu(2)S-Pd(4)S hybrid nanocrystals with a novel hexagonal nanoplate structure were prepared in high yield by a simple one-pot synthetic method (see figure). Successful synthesis of this unique structure was achieved through a consecutive thermolysis process. The Cu(2)S-Pd(4)S hybrid nanoplates exhibited substantially higher photocatalytic activities than pure Cu(2)S nanoplates.
View Article and Find Full Text PDFPd-Pt alloy nanocrystals (NCs) with hollow structures such as nanocages with porous walls and dendritic hollow structures and Pd@Pt core-shell dendritic NCs could be selectively synthesized by a galvanic replacement method with uniform Pd octahedral and cubic NCs as sacrificial templates. Fine control over the degree of galvanic replacement of Pd with Pt allowed the production of Pd-Pt NCs with distinctly different morphologies. The synthesized hollow NCs exhibited considerably enhanced oxygen reduction activities compared to those of Pd@Pt core-shell NCs and a commercial Pt/C catalyst, and their electrocatalytic activities were highly dependent on their morphologies.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2012
Octahedral Au nanocrystals with localized surface plasmon-assisted enhancing optical properties can be prepared in aqueous solution via the forced reduction of Au ions by ascorbic acid through the addition of NaOH.
View Article and Find Full Text PDF