Facile Wet Chemical Method Research Articles

Structural, Optical and Plasmonic Properties of Ag-TiO2 Hybrid Plasmonic Nanostructures with Enhanced Photocatalytic Activity

Hybrid plasmonic nanostructures consisting of Ag nanoparticles decorated TiO2 nanorods with highly enhanced photocatalytic activity were synthesized by a facile wet chemical method. The structural, optical, plasmonic and photocatalytic properties of the synthesized Ag-TiO2 hybrid nanostructures were well characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) with energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), Raman spectroscopy, photoluminescence spectroscopy (PL) and UV-visible absorption spectroscopy. The photocatalytic activities of the as-synthesized Ag-TiO2 hybrid nanostructures were evaluated by studying sun light-driven photocatalytic degradation of methylene blue (MB) and methyl orange (MO) dyes in water. The results showed that Ag-TiO2 hybrid nanostructures exhibit highly enhanced photocatalytic activity towards degradation of MB and MO dyes and the photocatalytic efficiency increased with increase in Ag nanoparticle loading. The mechanism underlying the highly enhanced photocatalytic activity of Ag-TiO2 nanohybrids is proposed. We attribute the observed enhanced photocatalytic activity of Ag-TiO2 hybrid nanostructures to the efficient separation of photogenerated charge carriers in TiO2 due to the electron scavenging action of Ag nanoparticles and the improved sun light utilization by the plasmonic nanohybrids originating from the surface plasmon resonance (SPR) absorption of Ag nanoparticles.

A Facile Synthesis of Size-Controllable IrO2 and RuO2 Nanoparticles for the Oxygen Evolution Reaction

The efficiency of the water electrolysis process is restricted by the sluggish kinetics of the oxygen evolution reaction (OER). Developing efficient catalysts and their synthesis methods is highly desired to improve the kinetics of the OER and therefore the overall efficiency of the water electrolysis. In this report, we present a facile wet-chemical method for synthesizing IrO2 and RuO2 nanoparticles (NPs) for the OER. The nanoparticles were synthesized by reducing metal chlorides in ethylene glycol in the presence of polyvinylpyrrolidone, followed by annealing in air. The particle size was controlled by adjusting the annealing temperature. The activity of IrO2 and RuO2 NPs supported on carbon black was investigated by cyclic voltammetry (CV) in alkaline (0.1 M KOH) electrolyte. As-synthesized IrO2 and RuO2 NPs showed high OER activity. The IrO2 NPs exhibited a specific activity of up to 3.5 (±1.6) μA/cm2 oxide at 1.53 V (vs. RHE), while the RuO2 NPs achieved a value of 124.2 (±8) μA/cm2 oxide. Moreover, RuO2 NPs showed a mass activity for OER, up to 102.6 (±10.5) A/goxide at 1.53 V (vs. RHE), which represents the highest value reported in the literature to date.

Fabrication, characterization and cellular biocompatibility of porous biphasic calcium phosphate bioceramic scaffolds with different pore sizes

Facile wet-chemical methods are applied to synthesize hydroxyapatite and β-tricalcium phosphate nanoparticles, respectively. Porous biphasic calcium phosphate (BCP) bioceramic scaffolds are then fabricated using as-prepared HA and β-tricalcium phosphate nanoparticle powders. The macro pore diameter of BCP bioceramic scaffolds can be controlled by adjusting the amount of surfactants. The average diameter of the macro pores in BCP bioceramic scaffolds increases from 100 to 600µm with the decrease amount of sodium dodecyl sulfate from 0.8 to 0.5g, respectively. The BCP bioceramic scaffolds gradually degrade and the calcium-phosphate compounds fully deposit when soaking in simulated body fluid solution. Moreover, The BCP bioceramic scaffolds have outstanding biocompatibility to promote the cellular growth and proliferation of human dental pulp stem cells (hDPSCs). The hDPSCs also demonstrate favorable cellular adhering capacity on the pore surface of scaffolds, especially on the scaffolds with 100–200µm pore diameter. The porous BCP bioceramic scaffold with inter-connected pore structure, outstanding in vitro cellular biocompatibility, favorable cell viability and adhesion ability will be a promising biomaterial for bone or dentin tissue regeneration.

Facile Fabrication of Binary Nanoscale Interface for No-Loss Microdroplet Transportation.

Binary nanoscale interfacial materials are fundamental issues in many applications for smart surfaces. A binary nanoscale interface with binary surface morphology and binary wetting behaviors has been prepared by a facile wet-chemical method. The prepared surface presents superhydrophobicity and high adhesion with the droplet at the same time. The composition, surface morphology, and wetting behaviors of the prepared surface have been systematic studied. The special wetting behaviors can be contributed to the binary nanoscale effect. The stability of the prepared surface was also investigated. As a primary application, a facile device based on the prepared binary nanoscale interface with superhydrophobicity and high adhesion was constructed for microdroplet transportation.

Fabrication of hybrid cauliflower-like nanoarchitectures by in situ grown ZnO nanoparticals on VS2 ultrathin nanosheets for high performance supercapacitors

Abstract A novel hybrid nanocomposite consisting of ZnO nanosphere wrapped with VS 2 ultrathin nanosheets (cauliflower-like nanoarchitecture) was successfully fabricated by a facile wet chemical method. ZnO nanospheres grew in situ on VS 2 nanosheets, which effectively restrained the restack of VS 2 nanosheets, leading three-dimensional (3D) nanostructure. With good electrical conductivity, big space void and high specific surface area, the as-prepared ZnO/VS 2 nanocomposite presents great potential as high-performance supercapacitor electrode. Detailed electrochemical characterizations show the intriguing structure exhibits extremely excellent supercapacitors performance including high specific capacitance (2695.7 F g −1 at a current density of 1 A g −1 ) and long term cycling stability (92.7% capacitance retention after 5000 cycles). This study provides the basis for the application of VS 2 -based hybrid nanoarchitectures in energy storage and other electrochemical devices.

Tailored synthesis of CuS nanodisks from a new macrocyclic precursor and their efficient catalytic properties on methylene blue dye degradation

In this study, CuS nanodisks have been synthesized from a tetraaza (N4) macrocyclic complex precursor by a facile wet chemical method. The crystallinity and morphology of the as-synthesized products were characterized by X-ray diffraction and transmission electron microscopy, which confirm a phase pure crystalline CuS nanostructures with ~15 to 20 nm in dimension with ~5 nm thickness. A possible formation mechanism and growth process of the CuS nanodisks are discussed using thiourea and tetraaza ligand as the sulfur donor and stabilizing agent, respectively. Cyclic N4 ligand also acts as a binding agent to template-guide the oriented growth of CuS nanodisks. The optimized geometry of ligands and complexes was calculated using B3YLP functional, which indicates that the HOMO in the complex located on metal center and N atoms are weakly bonded to the metal center. The catalytic activity of CuS nanodisks toward MB degradation with light displays the higher MB degradation rate than under dark in the presence of H2O2. The C t/C 0 plot as a function of time displays the higher MB degradation activity of CuS nanoparticles with H2O2. The recycle stability of CuS nanoparticles was even found to be >80 % after five cycles studied by repeating the MB degradation with same CuS nanoparticles sample. CuS nanostructures synthesized from a tetraaza macrocyclic complex precursor show the disk-like registry with average lateral dimension between 15 and 20 nm and thickness of 5 nm. The catalytic activity of CuS nanodisks toward MB degradation with light displays the higher MB degradation rate than in dark in the presence of H2O2.

Growth of transparent Zn1 − xSrxO (0.0 ≤ x ≤ 0.08) films by facile wet chemical method: Effect of Sr doping on the structural, optical and sensing properties

Zn1−xSrxO (0.0≤x≤0.08) nano-rods thin films are prepared using simple wet chemical technique on transparent flexible substrate. Effect of Sr-doping on structural and optical properties of ZnO is systematically investigated. SEM and TEM confirm the nano-rods like morphology with single crystalline nature of all the samples. Rietveld refinement of XRD shows the samples belongs to P63mc space group, furthermore, a gradual increment in lattice parameters and change in Zn/oxygen occupancy ratio is observed with Sr doping. SIMS and XPS confirm the doping of Sr in the ZnO nanostructures. XPS measurements shows that increase in Sr doping creates more oxygen associated defects, which is further supported by the photoluminescence spectra indicating the gradual change in Zn vacancy (Vzn) and oxygen interstitial (Oin) point defect intensities in the films. Near band edge emission peak shows to shift toward higher wavelength in the doped films. Pure ZnO film shows Raman peaks around 99(E2low), 333(E2high−E2low), 382 (A1 (TO)), 438(E2high) and 582 (A1 (LO) +E1 (TO)) cm−1, whereas two additional defect driven vibrational modes (at 277 and 663cm−1) are appeared in the Sr-doped films. The sensing property of the ZnO is enhanced by Sr doping and replicates as a promising material for future toxic and flammable gas sensor applications as well as for opto-electronic devices.

Ag-Au alloy nanoparticles: Synthesis and in situ monitoring SERS of plasmonic catalysis

Noble metal nanostructures are currently of great interest for their unique plasmonic property and potential applications in catalysis and surface-enhanced spectroscopy. However, the application of plasmonic nanostructures for quantitatively in situ SERS monitoring of the catalytic reaction has been a great challenge for investigators because combining plasmonics with catalysis requires the same kind of noble metal nanoparticles (NPs) in two very different size regimes. Herein, We have demonstrated a facile wet chemical method to synthesize Au-Ag alloy plasmonic NPs that could combine the desired plasmonic and catalytic properties with same NPs. The catalytic activity of Au-Ag alloy NPs using the reduction of 4-nitrothiophenol (4-NTP) by sodium borohydride (NaBH4) is chosen as a model reaction. The signals of the reaction processes are detected and identified through in situ SERS spectroscopy with high sensitivity. The insights gained by current study may serve as a promising and powerful technique for better investigation in the heterogeneous catalysis. Moreover, the reduction of aromatic nitro compounds with prepared Au-Ag alloy NPs also provides potential application in sewage treatment.

Realizing efficient upconversion and down-shifting dual-mode luminescence in lanthanide-doped NaGdF4 core–shell–shell nanoparticles through gadolinium sublattice-mediated energy migration

Monodisperse rod-like colloidal core–shell–shell NaGdF4:Yb/Tm@NaGdF4:Ce/Ln@NaYF4 (Ln = Tb, Eu, Dy and Sm) nanoparticles (25 nm in diameter and 37 nm in length) have been successfully synthesized through a facile wet chemical method. X-ray diffraction, transmission electron microscopy, upconversion and down-shifting photoluminescence were used to characterize the samples. The prepared nanoparticles exhibited both tunable upconversion and down-shifting emissions from Tb, Eu, Dy and Sm activators under 980 nm near-infrared and 254 nm ultraviolet excitation, respectively. The dual-model luminescence was achieved through gadolinium (Gd3+) sublattice-mediated energy migration: Yb3+ → Tm3+→n(Gd3+) → Ln3+ and Ce3+ → n(Gd3+)→Ln3+ energy-transfer process, respectively. The advances on these dual-mode luminescent nanoparticles offer exciting opportunities for developing multifunctional optical nanoprobes for biological applications.

Single Phase PtAg Bimetallic Alloy Nanoparticles Highly Dispersed on Reduced Graphene Oxide for Electrocatalytic Application of Methanol Oxidation Reaction

As renewable materials having high specific energy and environmentally safe characteristics, direct methanol fuel cells (DMFCs) have attracted huge interest to develop promising power devices with different strategies. Herein, single phase PtAg bimetallic alloy highly dispersed electrocatalyst on reduced graphene oxide (rGO) by a facile wet chemical co-reduction method. Different kinds of catalysts have been prepared with varying atomic ratios of Pt and Ag. Structural and morphological characterizations of as-synthesized catalysts are performed by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) and X-ray photoelectron diffraction (XPS) analysis. It is found that single phase PtAg bimetallic nanoparticles are successfully synthesized that are uniformly dispersed and attached on rGO sheets. High-angle annular dark-field scaning TEM (HAADF-STEM) and energy dispersive X-ray spectroscopic (EDX) analysis have also been performed, which confirm the single phase synthesis of uniformly dispersed PtAg bimetallic catalyst. MOR activity and durability has significantly increased by mutual coordination of both the metals in bimetallic nanocatalyst in comparison with the monometallic commercial Pt/C catalyst. The results can be attributed to the collective effects of the PtAg nanoparticles and the enhanced electron transfer characteristics of rGO sheets.

A gold electrode modified with silver oxide nanoparticle decorated carbon nanotubes for electrochemical sensing of dissolved ammonia

We have prepared silver oxide nanoparticles with a diameter of ~ 15 nm and decorated with carbon nanotube nanocomposites (Ag2O/CNT NCs) by a facile wet chemical method using reducing agents in alkaline medium. These NCs were characterized by UV/vis, FTIR and energy dispersive X-ray spectroscopy, by X-ray powder diffraction and field emission scanning electron microscopy. The NCs were then deposited on a flat gold electrode with the help of a conducting binder to result in an electrochemical sensor for aqueous ammonia using the I-V technique. Response is based on surface oxidation of ammonium hydroxide with electrode-adsorbed oxygen to form nitrogen oxide, these simultaneously liberating free electrons in the conduction band. Sensor features include a sensitivity of 32.856 μA.μM‾1.cm‾2, a low detection limit (1.3 pM at a signal to noise ratio of 3), reliability, reproducibility, ease of integration, and long term stability. The response to dissolved ammonia is linear (r2: 0.9778) over the 0.01 nM to 0.1 mM concentration range.

Copper and Graphene activated ZnO nanopowders for enhanced photocatalytic and antibacterial activities

ZnO, ZnO:Cu and ZnO:Cu:Graphene nanopowders were synthesized via a facile wet chemical method. The XRD studies show that the synthesized samples have hexagonal wurtzite structure. It is found that graphene addition induces a decrease in crystallite size. UV–vis absorption spectra of the samples show sharp absorption edges around 380nm. Photoluminescence studies reveal that the incorporation of copper and graphene in ZnO facilitates the efficient photo generated electron–hole pair separation. It is found that the ZnO:Cu and ZnO:Cu:Graphene nanopowder exhibit improved photocatalytic efficiency for the photodegradation of Methylene Blue (MB) under visible light irradiation. Moreover, improved antibacterial activity of ZnO:Cu:Graphene nanopowder against Escherichia coli and Staphylococcus aureus bacteria is observed.

Graphene-enhanced microwave absorption properties of Fe3O4/SiO2 nanorods

Fe3O4/SiO2/graphene composite composed of Fe3O4/SiO2 core–shell nanorods and graphene nanosheets were synthesized by a facile wet chemical method. Structure and morphology studies reveal that the Fe3O4/SiO2 nanorods with porous structure and large aspect ratio are densely wrapped by the graphene nanosheets. By changing the graphene content, the electromagnetic properties of the Fe3O4/SiO2/graphene composite can be well tuned. When the weight ratio of Fe3O4/SiO2 to graphene reaches an appropriate value, excellent microwave absorption performance is achieved due to the large electromagnetic losses and good impedance matching. The Fe3O4/SiO2/graphene composite with graphene content of 5wt.% shows the minimum reflection loss of −27.1dB at 12.2GHz when the coating layer thickness is only 1.5mm.

Facile wet chemical method for fabricating p-type BiOBr/n-type nitrogen doped graphene composites: Efficient visible-excited charge separation, and high-performance photoelectrochemical sensing

The development of highly efficient visible-excited charge separation photo active materials has attracted great attention for solving the global energy crisis and environmental problems. In this paper, p-type BiOBr nanoplates decorated n-type nitrogen doped graphene (BiOBr-NGR) composites are constructed by a facile wet chemical method. The formation of p-n junctions was beneficial to the efficient visible-excited charge transfer, and effectively restrains the recombination of photoinduced electron–hole pairs, resulting enhanced photoelectrochemical (PEC) performance. In particular, it is shown by means of the transient-state surface photocurrent responses that the photocurrent intensity of the as-fabricated composites exhibited 2.6 times higher than that of pristine BiOBr. Based on the robust photocurrent signal, a novel PEC sensor based on BiOBr-NGR was established for sensitive and selective detection of chlorpyrifos. The as-fabricated PEC sensor demonstrates many advantages such as wide linear range (5 pg mL−1–11.6 ng mL−1), low detection limit (1.67 pg mL−1, S/N = 3), and remarkably convenient, which provides a general format for chlorpyrifos detection in food and environment analysis.

Controlled fabrication of uniform Cu(OH)2 nanobelts via wet chemistry method

ABSTRACTIn this study, one-dimensional (1D) uniform Cu(OH)2 nanobelts have been synthesized by a facile wet chemistry method. The effect of different synthesis parameters on the morphologies of the target products was systematically studied. The uniform nanobelts can be easily controlled by different reaction time and temperature, while the quantity of ammonia adding in the solution has no obvious effect on the morphologies of Cu(OH)2 nanobelts. The optimum preparation condition of Cu(OH)2 nanobelts was that 0.42 g Cu(NO3)2•3H2O and 19 mL NH3•H2O solution was added into 100 mL of distilled water and heated at 60°C for 2 hours, and the morphologies and composition of the prepared samples were characterized by SEM, TEM and XRD, respectively.

Ultrasmall PdmMn1−mOx binary alloyed nanoparticles on graphene catalysts for ethanol oxidation in alkaline media

A rare combination of graphene (G)-supported palladium and manganese in mixed-oxides binary alloyed catalysts (BACs) have been synthesized with the addition of Pd and Mn metals in various ratios (G/PdmMn1−mOx) through a facile wet-chemical method and employed as an efficient anode catalyst for ethanol oxidation reaction (EOR) in alkaline fuel cells. The as prepared G/PdmMn1−mOx BACs have been characterized by several instrumental techniques; the transmission electron microscopy images show that the ultrafine alloyed nanoparticles (NPs) are excellently monodispersed onto the G. The Pd and Mn in G/PdmMn1−mOx BACs have been alloyed homogeneously, and Mn presents in mixed-oxidized form that resulted by X-ray diffraction. The electrochemical performances, kinetics and stability of these catalysts toward EOR have been evaluated using cyclic voltammetry in 1 M KOH electrolyte. Among all G/PdmMn1−mOx BACs, the G/Pd0.5Mn0.5Ox catalyst has shown much superior mass activity and incredible stability than that of pure Pd catalysts (G/Pd1Mn0Ox, Pd/C and Pt/C). The well dispersion, ultrafine size of NPs and higher degree of alloying are the key factor for enhanced and stable EOR electrocatalysis on G/Pd0.5Mn0.5Ox.

Effect of Ce doping into ZnO nanostructures to enhance the phenolic sensor performance

Various Ce-doped ZnO nanostructures (Ce/ZnO NSs) were prepared by a facile wet chemical method using reducing agents in alkaline medium.

Atom-diffusion enhanced electrocatalytic activity toward glucose oxidation on atacamite nanorods

The ability to design and characterise uniform nanoparticles with multi-anion group, where the less stable ligand enhances the diffusivity and activity of the metal ion, would be of broad interest in catalysis. In this paper, well dispersed Cu2Cl(OH)3 (atacamite) nanorods are synthesised via a facile wet chemical method. Electrochemical measurements demonstrate that the atacamite nanorods (ANRs) possess an enhanced electrocatalytic activity toward the oxidation of glucose. The ANRs-based electrode exhibits desirable catalytic performances with a short response time (<3 s), wide linear range (3 µM to 6 mM), and sound sensitivity (as high as 45.3 µA/mM). A high selectivity towards oxidation of glucose in the presence of oxygen, ascorbic acid, uric acid and dopamine is also observed. The good electrochemical properties are attributed to the intrinsic atomic diffusivities and electron transport efficiency at the liquid-solid interface, which makes such mixed oxides promising for wide applications in non-enzymatic biofuel cells and biosensors.

Synthesis and characterization of Cu–MoS2 hybrids and their influence on the thermal behavior of polyvinyl chloride composites

In this work, Cu–MoS2 hybrids were synthesized by a facile wet chemical method.

Enhanced CO gas sensing properties of Cu doped SnO2 nanostructures prepared by a facile wet chemical method.

We report the synthesis of Cu doped SnO2 nanostructures with enhanced CO gas sensing properties by a facile wet chemical method. The effects of Cu doping on the structural and optical properties of SnO2 nanostructures were investigated using X-ray diffraction, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high resolution TEM (HRTEM) with energy dispersive X-ray spectroscopy, Raman spectroscopy and photoluminescence spectroscopy. FESEM studies revealed the presence of nanosheets and nanodisc-like structures in Cu doped SnO2 samples. Gas sensing studies showed that the sensor prepared using 1% Cu doped SnO2 nanostructures exhibits highly enhanced CO gas sensing properties as compared to pure SnO2 nanostructures and shows excellent selectivity for CO with negligible interference from CH4, CO2 and NO2. The possible mechanism for the enhanced CO gas sensing properties of Cu doped SnO2 nanostructures is proposed.