The Exploration On Synthesis Of Copper Nanowires And Associated Oxide Derivative Nanomaterials For Advanced Applications

Copper nanowires(Cu NWs),as one kind of most dramatic one-dimensional(1D)nanoscale building blocks,have made a deep impact on nanomaterials science related research,and are being explored for applications in several disciplines such as energy conversion devices and optoelectronic devices.Although the desired advanced properties have been demonstrated,these materials cannot yet be produced in large-bulk quantities in order to bridge the technological transfer gap for wider use.In this respect,the quest for the most efficient synthesis process which yields not only large quantities but also high quality and advanced material properties continues.Furthermore,how to fully exploit and reconstruct such copper-based 1D nanostructure is another serious challenge.Herein,this paper first gives an extensive study of Cu NWs synthesis by various methods and routes.These methods are critically designed,executeed and evaluated,which we divide into two categories:(i)wet-chemical methods based on solution growth as well as hydrothermal routes;(ii)chemical vapour synthetic route involving pyrogenic decomposition and direct oxidation with combination of post-reduction method.Especially,fivefold twinned Cu NW products with diameters around 100 nm and lengths over 10 ?m can be obtained by using polyol process and hydrothermal method.It is worth mentioning that the NWs prepared by hydrothermal method also process amorphous carbon sheath,resulting in good antioxidative stability.In addition,modified chemical vapor-phase pyrolysis method could produce Cu@C NWs with outer diameters between 40 and 150 nm and lengths ranging from 5 ?m up to 10 ?m.These methods not only yield large quantities of NWs,but produce high quality material.Second,we further provided in-depth explorations of associated oxide derivative(i.e.,cuprous oxide and cupric oxide)hierarchical nanostructures and heterostructures with Cu NW as the central component,discussed growth of as-obtained nano-architectures,described the properties of nanoscale components and interfaces/junctions,and elaborated by highlighting optoelectronic,electronic and energy-related applications in subsequent study.It can be found that branched Cu2 O NWs demonstrate significantly improved H2 yield of up to ca.263.8 mmol/h from photocatalytic water splitting;branched Cu@Cu2O NWs reveal a successful integration of the ultrahigh sensitivity(1420.7 ?A /mMcm~2),the low detection limit(40 nM)and the fast response(within 0.1 second);while the function of branched Cu/Cu2O/CuO NWs as Li-ion batteries anode exhibits superb performance in term of capacity and cycling.Such a hierarchical framework incorporates multiple advantageous features,including(i)the three-dimensional hierarchical architecture provides large specific surface areas for more active catalytic sites and easy accessibility for the target molecules;(ii)for heterogeneous hierarchical structure,the high-quality heterojunction with minimal lattice mismatch between the built-in current collector(Cu core)and active medium(Cu2O or Cu2O/CuO shell)considerably promotes the electron transport;(iii)moreover,the nanoscale diameter and high aspect ratio of nanowires are the foundation of fascinating structure-property relationships derived from confinement,interface effects,and mechanical degrees of freedom.Thus,a cooperative effect between the low-dimensional components and their interfaces within proposed complex 3D architectures or heterostructures on the basis of NWs can give rise to novel functions and promoted performance which cannot be realized from each of the components separately.While we herein put emphasize on copper as model system,we believe that our results will also play a steering role in investigations of other metal systems such as nickel,iron,stannum and cobalt for future energy conversion/storage and optoelectronic applications with strong competitiveness.