Preparation And Catalytic Performance Of Copper Nanocomposites And Cuprous Oxide Nanocomposites

Due to rich raw material and low price,copper-based nanomaterials which show unique physical and chemical properties are widely noted. Cu nanomaterials as a transition metal,which possess excellent catalytic, electrical, mechanical and optical properties, are exploited in electrocatalyst, electronics, senors and surface enhanced Raman scattering. Cu2 O is a typical direct band-gap p-type semiconductor with a narrow band gap(~2.1 eV) and a high optical absorption coefficient for visible light,which is attractive for photocatalysts,solar cells and gas sensing applications.Nanocomposite materials as a composites containing nanoscale constituents possess the independent properties of each component as well as new synergistic and enhanced performances. In this paper, Cu nanowires(NWs) nanocomposites and Cu2 O nanocomposites were synthesized by simple wet-chemical methods and applied to catalysts. In addition, the relationship between structures of nanocomposite materials and catalytic performance were explored. The main contents in this paper were listed as follows:1. A nanocomposite compositing of one-dimensional copper nanowires and two-dimensional reduced graphene oxide nanosheets(CuNWs/rGO) was synthesized by a one-step wet chemical approach. The CuNWs anchored onto the rGO nanosheets with wrinkles and folds had a smooth surface. The CuNWs/rGO hybrids exhibited excellent electrocatalytic activity toward glucose oxidation due to the superior conductivity along one-dimensional direction and excellent catalytic activity of CuNWs and large specific surface area and rapid electron transfer in the two-dimensional rGO sheets. A high sensitivity(1625 μA /(mM?cm-2)),low detection limit(0.2 μM), wide linear range up to 11 mM and fast response(<3 s) to glucose oxidation were obtained under a working potential of 0.58 V for the hybrid with optimized Cu/rGO mass ratio in the alkaline solution. Furthermore, the CuNWs/rGO composites displayed high selectivity to glucose and resistance against poisoning by commonly interfering species such as ascorbic acid, dopamine, uric acid, acetamidophenol and some carbohydrates. The CuNWs/rGO hybrids were therefore promising for the potential application as non-enzymatic amperometric glucose sensors.2. A series of one-dimensional Cu-based heterostructures,such as Au nanoparticles(3-5 nm)coated Cu nanowires, Au3 Cu alloy porous nanotubes, were synthesized through combiningmodified galvanic replacement reactions with the Kirkendall effect by using Cu nanowires as the sacrificial template. Compared with the current methods to prepare one-dimensional Cu-based heterostructures using hard template, it was convenient to control the compositions and morphologies of the one-dimensional Cu-based heterostructures by changing the reactant molar ratio of Cu/HAuCl4. Towards the chemocatalysis of the reduction of 4-nitrophenol, the one-dimensional Cu-based heterostructures exhibited excellent catalytic performance superior to Cu nanowires. Especially, due to the specific nanostructure and synergistic effect of their constituents, the Au3 Cu alloy nanotubes showed the most outstanding catalytic performance.This study offered a simple strategy that could achieve large-scale preparation of different one-dimensional Cu-based heterostructures as catalysts.3. Hollow Au@Cu2O core-shell nanoparticles were synthesized by using hollow gold nanoparticle(HGN) as the plasmon-tailorable cores to direct epitaxial growth of Cu2 O nanoshells. The effective geometry control of hollow Au@Cu2O core-shell nanoparticles was achieved through adjusting the HGN core size, Cu2 O shell thickness and morphology related to structure-directing agents. The morphology-dependent plasmonic band redshifts across the visible and near-infrared spectral regions were observed from experimental extinction spectra and theoretical simulation based on the Finite-difference time-domain method. Moreover, the hollow Au@Cu2O core-shell nanoparticles with synergistic optical properties exhibited higher photocatalytic performance in the photodegradation of methyl orange compared to pristine Cu2 O under visible-light irradiation due to the efficient photoinduced charge separation, which could mainly be attributed to the Schottky barrier and plasmon-induced resonant energy transfer.