Effect of Electrodeposition Methods of Cuprous Oxide on Antibacterial Properties of Concrete

Three types of electrodeposition,DC electrodeposition,low-frequency pulsed electrodeposition and high-frequency pulsed electrodeposition,were used to deposit cuprous oxide on the concrete surface to improve the antibacterial properties of concrete.The effects of pulse deposition frequency on the antibacterial property of concrete were studied using sulfate-reducing bacteria(SRB)and Escherichia coli(E.coli)as model bacteria.The bacterial concentration and the antibacterial rate were measured to evaluate the antibacterial performance of concrete.The effects of different deposition methods on the elemental content of copper and the amount of copper ions exuded were studied.XRD and SEM were used to analyze the microstructure of the deposited layers.The experimental results show that the concrete treated by electrodeposition exhibited good antibacterial properties against SRB and E.coli.The antibacterial effect of cuprous oxide deposited on concrete by pulse method was better than that by direct current(DC)method.The antibacterial rate of concrete was positively correlated with the exudation rate of copper ion.As the pulse frequency increased,the deposits content on the surface was increased with an accompanying improvement in the antibacterial property.Besides,the pulsed current had an indiscernible effect on the composition of the sediments,which were all mainly composed of Cu_(2)O,but the morphology of the Cu_(2)O differed greatly.Cubic octahedral cuprous oxide had better antibacterial properties with the highest copper ion leaching rate compared with cubic and spherical cuprous oxide.

Morphology control of ultrafine cuprous oxide powder and its growth mechanism

Four shapes of Cu2O particles as sphere,cube,truncated octahedron and octahedron were prepared via glucose reduction of Cu(Ⅱ)under alkaline condition.The products were characterized by XRD and SEM.The effects of the precursor(CuO,Cu(OH)2), reaction temperature and glucose concentration on morphology of Cu2O particles were investigated,and the mechanism of morphology control was discussed on the basic theory of crystal nucleation and growth.It is found that the Cu+supersaturation is remarkably influenced by the precursor kind,reaction temperature and glucose concentration,and the morphology of Cu2O particles can be controlled by the Cu+supersaturation.

Facile Synthesis of Mesoporous Cuprous Oxide Nanoparticles for Enhanced Visible-light-driven Photodegradation

The visible-light-active mesoporous cuprous oxide nanoparticles were successfully synthesized via a facile precipitation process with the presence of gelatin, which was demonstrated to play an important role in the formation of mesoporous structure and the grain size control. The nanoscale grain size and mesoporous structure lead to lager specific surface area with the addition of gelatin. Furthermore, the photodegradation of as-prepared catalysts in the presence of gelatin toward the negatively charged methyl orange（MO） was investigated. The cuprous oxide displayed an excellent visible light photocatalytic activity of MO, owing to its exposed active（111） face and large specific surface area. The adsorption of positively charged methyl blue（MB） revealed that the mesoporous cuprous oxide displayed better adsorption of anionic dye MB due to the residual gelatin on the surface of the grains, compared to that in the absence of gelatin.

Effect of Additives on the Morphologies of Cuprous Oxides by Electrodeposition

Cuprous oxides with different morphologies were formed on F-doped tin oxide （FTO） covered glass substrates by potentiostatic deposition of cupric acetate. The effects of CTAB and Cl- on the crystal morphologies of cuprous oxide were studied. Different crystal morphologies of cuprous oxides were obtained by the change of the concentrations of CTAB and Cl. The flowerlike and cubic morphologies of Cu2O crystals were obtained when using higher concentration of CTAB and KCl, respectively. Photoelectrochemical properties of the Cu2O thin films prepared in the system were also studied.

Cuprous oxide/copper oxide interpenetrated into ordered mesoporous cellulose-based carbon aerogels for efficient photocatalytic degradation of methylene blue

The casual discharge of dyes from industrial settings has seriously polluted global water systems.Owing to the abundance of biomass resources,preparing photocatalysts for photocatalytic degradation of dyes is significant;however,it still remains challenging.In this work,a cuprous oxide/copper oxide composite was interpenetrated onto carbon nanosheets of cellulose-based flexible carbon aerogels(Cu_(2)O/CuO@CAx)via a simple freeze-drying-calcination method.The introduction of the carbon aerogel effectively prevents the aggregation of the cuprous oxide/copper oxide composite.In addition,Cu_(2)O/CuO@CA0.2 has a larger specific surface area,stronger charge transfer capacity,and lower recombination rate of photogenerated carriers than copper oxide.Moreover,Cu_(2)O/CuO@CA0.2 exhibited high photocatalytic activity in decomposing methylene blue,with a degradation rate reaching up to 99.09% in 60 min.The active oxidation species in the photocatalytic degradation process were systematically investigated by electron spin resonance characterization and poisoning experiments,among which singlet oxygen played a major role.In conclusion,this work provides an effective method for preparing photocatalysts using biomass resources in combination with different metal oxides.It also promotes the development of photocatalytic degradation of dyes.

Microwave Synthesis of Cuprous Oxide Micro-/Nanocrystals with Different Morphologies and Photocatalytic Activities

Cuprous oxide micro-/nanocrystals were synthesized by using a simple liquid phase reduction process under microwave irradiation. Copper sulfate was used as the starting materials and macromolecule surfactants served as the templates. The morphologies phase and optical properties of them are characterized by X-ray diffraction （XRD）, scanning elec- tron microscopy （SEM） and ultraviolet-visible diffuse reflection absorptive spectra （UV-vis/DRS）, respectively. The crystals had four different shapes, namely spheres, strips, octahedrons, and dandelions. The photocatalytic behavior of the cuprous oxide particles were investigated by monitoring the degradation of rhodamine B. In spite of the differ- ent morphologies, all of the cuprous oxide micro-/nanocrystals exhibited photocatalytic activities under visible light irradiation in the following order： dandelions, strips, spheres, and octahedral crystals. The photocatalytic degradation rates of rhodamine B are 56.37%, 55.68%, 51.83% and 46.16%, respectively. The morphology affects significantly the photocatalytic performance.

Template Effect of Hydrophobically Associating Polymers on the Construction of Cuprous Oxide Micro Structure

To determine the template effect of hydrophobically associating copolymers（HACPs） on the morphology of nano/micro structures, six HACPs were synthesized and used as templates to biomimetically synthesize cuprous oxide（Cu2O）, an important semiconductor. This experiment showed a clear relationship between the associating state of the HACP molecules and the morphology of the Cu2O particles. Cu2O hollow spheres were preferentially prepared when the HACP molecules were in an intramolecular associating state. Furthermore, a Cu2O hexapod was easily obtained when the HACP molecules were in an intermolecular associating state. The morphologies of the Cu2O crystals prepared in the presence of the HACPs also confirmed this result.

A simple single-step approach towards synthesis of nanofluids containing cuboctahedral cuprous oxide particles using glucose reduction

Enhancement of thermal properties of conventional heat transfer fluids has become one of the important technical challenges. Since nanofluids offer a promising help in this regard, development of simpler and hassle free routes for their synthesis is of utmost importance. Synthesis of nanofluids using a hassle free route with greener chemicals has been reported. The single-step chemical approach reported here overcomes the drawbacks of the two-step procedures in the synthesis of nanofluids. The resulting Newtonian nanofluids prepared contained cuboctahedral particles of cuprous oxide and exhibited a thermal conductivity of 2.852 W- m-1. K-1. Polyvinylpyrro- lidone （PVP） used during the synthesis acted as a stabilizing agent rendering the nanofluid a stability of 9 weeks.

Amino-Functionalized Reduced Graphene-Oxide-Copper (I) Oxide Composite: A Prospective Catalyst for Photo-Reduction of CO2

In the present article, an easy synthetic strategy of a novel composite photo-catalyst comprising of amino-functionalized reduced graphene oxide and Cu2O has been proposed. Role of this composite catalyst in photo reduction of CO2 has been analyzed and it is shown that both amino groups and reduced grapheme oxide, participate in enhancing quantum yield of the photo reduction process.

Ultrafast carrier dynamics of Cu_(2)O thin film induced by two-photon excitation

Cuprous oxide(Cu_(2)O)has attracted plenty of attention for potential nonlinear photonic applications due to its superior third-order nonlinear optical property such as two-photon absorption.In this paper,we investigated the two-photon excitation induced carrier dynamics of a Cu_(2)O thin film prepared by radio-frequency magnetron sputtering,using the femtosecond transient absorption experiments.Biexponential dynamics including an ultrafast carrier scattering(<1 ps)followed by a carrier recombination(>50 ps)were observed.The time constant of carrier scattering under two-photon excitation is larger than that under one-photon excitation,due to the different transition selection rules and smaller absorption coefficient of the two-photon excitation.

pH Controlled Synthesis of Tetragonal Cu₂O Particles

Cuprous oxide (Cu2O) in high yield with controlled shape and size was synthesized via a solution-phase route by reducing cupric sulphate with D-glucose. The solution pH shows strong effects on the size and morphology of the products. The products were characterized by X-ray power diffraction (XRD) and Scanning electron microscope (SEM). The infrared emissivity of Cu2O was tested by Far infrared emissivity measurer S302. The possible crystal growth processes have been proposed.

Kinetics Study on Photocatalytic Degradation of Methyl Orange Catalyzed by Sea Urchin-Like Cu2O

Sea urchin-like cuprous oxide with hollow glass microsphere as core was prepared using sodium sulfite as the reducing agent and sodium acetate-acetic acid as buffer solution in copper sulfate solution. Methyl orange was selected as degradation target for photocatalytic experiments. The photocatalytic activities were investigated by visible spectro- photometer. Photocatalytic kinetics parameters were studied by the Langmuir-Hinshelwood model and Arrhenius formula. It was observed that the sea urchin-like morphology dramatically improved the photocatalytic activity of cuprous oxide. The photo-degradation belongs to the first-order reaction and the maximum degradation rate could reach 94.37%. The activation energy and pre-exponential factor are 41.18 KJ·mol-1 and 1.07 × 106, respectively. After seven times recycling, the sample still showed high photo-catalytic efficiency and stability.

Optical Analysis of a ZnO/Cu_(2)O Subcell in a Silicon-Based Tandem Heterojunction Solar Cell

Research on silicon-based tandem heterojunction solar cells (STHSC) incorporating metal oxides is one of the main directions for development of high-efficiency solar cells. In this work, the optical characteristics of a STHSC consisting of a ZnO/Cu2O subcell on top of a silicon-based subcell were studied by optical modelling. Cu2O is a direct-gap p-type semiconductor which is attractive for application in solar cells due to its high absorptance of ultra-violet and visible light, nontoxicity, and low-cost producibility. Highly Al-doped ZnO and undoped Cu2O thin films were prepared on quartz substrates by magnetron sputter deposition. Thermal annealing of the Cu2O layer at 900°C enhances the electrical properties and reduces optical absorption, presumably as a result of increased grain size. Hall effect measurements show that the majority carrier (hole) mobility increases from 10 to 50 cm2/V×s and the resistivity decreases from 560 to 200 Ω×cm after annealing. A Cu2O absorber layer of 2 μm thickness will generate about 10 mA/cm2 of photocurrent under AM1.5G illumination. The optical analysis of the STHSC involved calculating the spectral curves for absorptance, transmittance, and reflectance for different thicknesses of the thin film layers constituting the ZnO/Cu2O subcell. The complex refractive indices of the thin films were derived from spectroscopic ellipsometry measurements and implemented in the simulation model. The lowest reflectance and highest transmittance for the ZnO/Cu2O subcell are obtained for a thickness of approximately 80 nm for both the top and bottom AZO layers. The SiNx anti-reflection coating for the c-Si bottom subcell must be optimized to accommodate the shift of the photon spectrum towards longer wavelengths. By increasing the thickness of the SiNx layer from 80 nm to 120 nm, the total reflectance for the STHSC device is reduced from 12.7% to 9.7%.

Visible-Light Photocatalytic Conversion of Carbon Dioxide into Methane Using Cu_(2)O/TiO_(2) Hollow Nanospheres

In the past few decades there has been a remarkable rise in the study of visible-light photocatalytic reduction of carbon dioxide (CO_(2)) into value-added chemicals such as methane (CH4) with water as reducing agent in order to prevent global warming and energy crisis. However, so far the conversion efficiency leaves much to be enhanced under sunlight irradiation. In this work, Cu_(2)O hollow nanospheres were synthesized via soft-template method and were combined with TiO_(2) through in-situ hydrolysis of Ti(OBu)4 under sonication. The obtained photocatalysts of Cu_(2)O and Cu_(2)O/TiO_(2) composite were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, UV-visible diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. Compared to Cu_(2)O hollow nanospheres, the Cu_(2)O/TiO_(2) composite exhibited higher efficiency in photocatalytic reduction of CO_(2) into CH4 under visible-light irradiation (λ≥420 nm). This is because of the formation of a p-n heterojunction in the composites, resulting in efficient suppression of recombina- tion of the photogenerated electrons and holes as well as an improved stability of the catalyst and, thereby, the im- proved visible-light photocatalytic activity.

Enhancement of visible-light-driven oxidative amine coupling under aerobic and anaerobic conditions by photocatalyst with spatial separation of photoinduced charge carriers

Spatial separation of oxidation/reduction cocatalyst is an effective means to improve the efficiency of charge separation in photocatalytic reaction systems.Herein,a yolk-shell Pd@NH_(2)-UiO-66@Cu_(2)O heterojunction was designed and synthesized by integration of electron collector Pd and hole collector Cu_(2)O inside and outside of a photoactive metal-organic framework(MOF)NH_(2)-UiO-66,respectively.The obtained Pd@NH_(2)-UiO-66@Cu_(2)O heterojunction effectively inhibits the electron and hole recombination through the photo-induced electrons and holes flow inward and outward of the composite,and promotes the reduction and oxidation abilities for the oxidative coupling of benzylamine to imines.Compared with Pd/NH_(2)-UiO-66@Cu_(2)O,Pd@NH_(2)-UiO-66,and Pd/NH_(2)-UiO-66,Pd@NH_(2)-UiO-66@Cu_(2)O exhibits the highest photocatalytic activity.More importantly,Pd@NH_(2)-UiO-66@Cu_(2)O shows a conversion rate of benzylamine up to 99%either by oxidation under aerobic conditions or by strong adsorption of H atom(Hads)under anaerobic conditions.In addition,the catalyst shows good stability and can be recycled at least ten times.This work provides useful guidance on construction of MOFs-based composites with spatially separated photoinduced charge carriers to realize efficient oxidation coupling of benzylamine in both aerobic and anaerobic conditions.

TiO_(2)/Cu_(2)O heterostructure enabling selective and uniform lithium deposition towards stable lithium metal anodes

Lithium(Li)metal is the ultimate anode choice for next generation high energy density batteries.However,the high nucleation energy barrier and nonuniform electric field distribution,as well as huge volume expansion,lead to the uncontrollable growth of Li dendrites and poor utilization of Li metal,which hinders its practical application.Herein,titanium dioxide/cuprous oxide(TiO_(2)/Cu_(2)O)heterostructure is constructed on the rimous skeleton of Cu mesh,and the heterostructure decorated rimous Cu mesh(H-CM)can act as both current collector and host for dendrite-free Li metal anode.The TiO_(2)/Cu_(2)O heterostructure realizes selective Li nucleation by nano TiO_(2)and then induces fast and uniform Li conduction with the aid of heterostructure interface and nano Cu_(2)O contributing to dendrite-free Li deposition.While the internal and external space of rimous skeletons in H-CM is used to accommodate the deposited Li and buffer its volume change.Therefore,the cycling reversibility of the derived Li metal anode in H-CM is improved to a high Coulombic efficiency of 98.8%for more than 350 cycles at a current density of 1 mA·cm−2,and 1,000 h(equals to 500 cycles)stable repeated Li plating/stripping can be operated in a symmetric cell.Furthermore,full cells with limited Li anode and high loading LiFePO4 cathode present excellent cycling and rate performances.

In Situ Loading of Cu_(2)O Nanoparticles on a Hydroxyl Group Rich TiO_(2) Precursor as an Excellent Catalyst for the Ullmann Reaction

An in situ method has been used to load Cu_(2)O nanoparticles on the surface of a hydroxyl group rich TiO_(2)precursor.Cu_(2)O nanoparticles are formed by in situ reduction of Cu(OH)_(2) with Sn^(2+)ions linked to the surface of the TiO_(2)precursor.The initial Cu_(2)O nanoparticles serve as seeds for subsequent particle growth.The resulting Cu_(2)O nanoparticles are evenly dispersed on the surface of the TiO_(2)precursor,and are heat and air stable.The as-prepared composite is an excellent catalyst for Ullmann type cross coupling reactions of aryl halides with phenol.The composite catalyst also showed good stability,remaining highly active after five consecutive runs.

Nature-inspired Cu2O@CoO tree-like architecture for robust storage of sodium

We report a nature-inspired design of tree-like architecture of cuprous oxide(Cu2O)stem and cobalt oxides(CoO)branch serving as an efficient anode for sodium-ion batteries.The construction of stembranch architectures involves the growth of Cu2O nanorods and the subsequent deposition of CoO nanowires.Due to abundant active sites and full exposure to electrolyte,such a Cu2O@CoO stem-branch architecture demonstrates a robust storage toward Na^+ions,affording a capacity retention of^100%over 300 continuous cycles and a remarkable rate capability of 296 mAh g^-1 at 1 A g^-1.This result clearly shows the potential of nature-inspired materials engineering may find extensive applications in the design of high-performance electrodes for rechargeable batteries.

A ultrasensitive nonenzymatic glucose sensor based on Cu_2O polyhedrons modified Cu electrode

A novel nonenzymatic glucose sensor was successfully fabricated based on the Cu2O polyhedrons covered Cu foil. The Cu2O polyhedrons covered Cu foil was constructed via a facile, low-cost and larger scale producible method. The Cu2O polyhedrons covered Cu foil can be directly used as the working electrode of nonenzymatic glucose sensor, which present good stability and flexibility. The results indicated that the Cu2O polyhedrons modified Cu electrode （Cu2O/Cu electrode） showed high electrocatalytic activity for the oxidation of glucose in alkaline solution. There are two linear regions of glucose concentration for the glucose sensor based on Cu2O/Cu electrode, respectively in 10μmol/L to 0.53 mmol/L （sensitivity： 3029.33 μA （mmol/ L）^-1 cm^-2） and in 0.53-7.53 mmol/L （sensitivity： 728.67 μA （rnmol/L）^-1 cm^-2）.

Effect of Oxygen Content on Structural and Optical Properties of Single Cu_2O Film by Reactive Magnetron Sputtering Method

Cuprous oxide(Cu_2O) thin films have been deposited on glass substrate by reactive magnetron sputtering method using Cu target and argon oxygen gas atmosphere.Effect of oxygen flow rate on structural and optical properties of thin films has been discussed.The results of X-ray diffraction,ultraviolet-visible spectrophotometry and atomic force micrograph indicated that the condition window for single Cu_2O phase was about 3.8 to 4.4 cm^3/min,and the optimum oxygen flow rate was 4.2 cm^3/min.The optical band gap E_g of Cu_2O film was determined by using the data of transmittance versus wavelength,and slightly decreased from 2.46 to 2.40 eV with the increase of oxygen flow rate from 3.8 to 4.4 cm^3/min.The Cu_2O film formed at the oxygen flow rate of 4.2 cm^3/min had an optical band gap of 2.43 eV.