CdS Content Research Articles

Hydrophobicity and aromaticity are primary factors shaping variation in amino acid usage of chicken proteome.

Amino acids are utilized with different frequencies both among species and among genes within the same genome. Up to date, no study on the amino acid usage pattern of chicken has been performed. In the present study, we carried out a systematic examination of the amino acid usage in the chicken proteome. Our data indicated that the relative amino acid usage is positively correlated with the tRNA gene copy number. GC contents, including GC1, GC2, GC3, GC content of CDS and GC content of the introns, were correlated with the most of the amino acid usage, especially for GC rich and GC poor amino acids, however, multiple linear regression analyses indicated that only approximately 10–40% variation of amino acid usage can be explained by GC content for GC rich and GC poor amino acids. For other intermediate GC content amino acids, only approximately 10% variation can be explained. Correspondence analyses demonstrated that the main factors responsible for the variation of amino acid usage in chicken are hydrophobicity, aromaticity and genomic GC content. Gene expression level also influenced the amino acid usage significantly. We argued that the amino acid usage of chicken proteome likely reflects a balance or near balance between the action of selection, mutation, and genetic drift.

Synthesis of nanocomposite CdS/TiO2 and investigation of its photocatalytic activity for CO2 reduction to CO and CH4 under visible light irradiation

CdS–TiO2 nanocomposites were synthesized with various CdS weight ratios of 9%, 23%, 45% and 74% by the hydrothermal process. The prepared samples were characterized by X-ray diffraction (XRD), UV–visible diffuse reflectance spectroscopy (DRS), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS) and Brunauer–Emmett–Teller (BET) analysis. Samples were coated on the surface of the perforated stainless steel and the photocatalytic activity of the catalysts was investigated under both UV–visible and visible irradiation to convert CO2 to carbon monoxide and methane. Significant improvement was observed for the activity of CdS–TiO2 nanocomposites compared with pure nano TiO2 under both UV–visible and visible light scattering in a batch gaseous reactor. The activity of CdS–TiO2 nanomaterial was found to be related to the CdS content and the size of nanoparticles. Maximum photocatalytic activity was observed for an optimal weight ratio of 45% CdS/TiO2 with 13nm average crystal size. The photocatalytic experiments were taken for 8h and formation of CO and CH4 was detected in gas phase, whereas CO production was five folds more than methane formation. Under UV–visible irradiation, photocatalytic activity of CdS–TiO2 for CO and CH4 formation was observed 35% and 50%, respectively, more than that under visible light.

Synthesis of CdS/BiOBr composite and its enhanced photocatalytic degradation for Rhodamine B

CdS/BiOBr composite photocatalysts were successfully prepared by a facile precipitation method and characterized by XRD, SEM, TEM, EDS, UV–vis and PL. The photocatalytic activities of the samples were evaluated by the degradation of Rhodamine B (RhB) under visible light irradiation. The effects of CdS content, catalyst dosage, and initial concentration of RhB solution on the photocatalytic degradation were investigated. The results indicated that the CdS/BiOBr composite photocatalysts exhibited strong absorption in the visible light region and possessed excellent photocatalytic activity and stability for RhB degradation. The 40%-loaded CdS/BiOBr composite photocatalyst was found to degrade 97% of RhB under visible light irradiation and showed no apparent decrease in activity after five cycles. The enhancement in both activity and stability were attributed to the enhanced light absorption and effective separation and transfer of photogenerated charges, originating from the well-matched overlapping band-structures and closely contacted interfaces. Experiments using radical scavengers indicated that O2− and h+ were the main reactive species present in the photosystem. On the basis of the experimental results and estimated energy band positions, the mechanism for the enhanced photocatalytic activity was proposed.

A g-C3N4–CdS composite catalyst with high visible-light-driven catalytic activity and photostability for methylene blue degradation

A straightforward strategy is designed to fabricate g-C3N4–CdS composite catalyst with high visible-light-driven photocatalytic activity and photostability via the precipitation method. The microscopic observation shows that CdS nanoparticles are randomly distributed on the surface of graphitic carbon nitride (g-C3N4), and X-ray diffraction (XRD) measurements and Fourier transform infrared (FT-IR) spectra further confirm that g-C3N4 and CdS coexist in the photocatalysts. The results of photocatalytic experiments demonstrate that the g-C3N4–CdS composite exhibits significantly enhanced photocatalytic activity for the photocatalytic degradation of methylene blue (MB) compared with g-C3N4 or CdS alone under visible-light irradiation. It is found that the photocatalytic degradation process follows the pseudo-first-order kinetic model and Langmuir–Hinshelwood model, indicative of an adsorption controlled reaction mechanism. The enhanced photocatalytic activity of the g-C3N4–CdS composite can be attributed to the large surface area and the synergistic effects between g-C3N4 and CdS, which can readily reduce the recombination probability of photogenerated electron-hole pairs and enhance the charge separation efficiency, leading to the higher photocatalytic performance and effectively inhibited photocorrosion. The results also show that among the catalysts with differing CdS content, the g-C3N4–CdS composite with a g-C3N4/CdS mass ratio of 1:3 exhibits the highest photodegradation efficiency (90.45%) after irradiation for 180min.

Insight into band positions and inter-particle electron transfer dynamics between CdS nanoclusters and spatially isolated TiO2dispersed in cubic MCM-48 mesoporous materials: a highly efficient system for photocatalytic hydrogen evolution under visible light illumination

CdS incorporated Si-MCM-48 and Ti-MCM-48 cubic phased mesoporous photocatalysts were prepared by a two-step modification synthetic approach under relatively mild conditions. A highly efficient (24.8%, apparent quantum yield (AQY)) photocatalyst for visible light (λ > 400 nm) enabled solar hydrogen evolution can be realized by assembling CdS with Ti-MCM-48 cubic mesoporous materials in the absence of a noble metal co-catalyst. The photocatalytic mechanism was thoroughly investigated and demonstrated by conducting a wealth of characterization techniques such as powder X-ray diffraction (XRD), nitrogen adsorption isotherm, transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UVPS), atomic absorption spectroscopy (AAS), photoluminescence (PL) spectroscopy, time-resolved fluorescence emission decay, and electron paramagnetic resonance (EPR) spectroscopy studies. This work is the first to unambiguously identify the band positions of both CdS and TiO2 encapsulated in porous materials. The photocatalytic activity of the CdS incorporated Ti-MCM-48 mesoporous photocatalysts was found to be dependent on the content of both CdS and TiO2. A correlation between the electron injection efficiency and the photocatalytic activity was established as well in the CdS incorporated Ti-MCM-48 mesoporous photocatalysts.

Stable hydrogen generation from vermiculite sensitized by CdS quantum dot photocatalytic splitting of water under visible-light irradiation.

CdS quantum dot/vermiculite (CdS/VMT) nanocomposites have been synthesized via a facile one-step method and characterized by X-ray diffraction, UV-vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The photocatalytic hydrogen generation activities of these samples were evaluated using Na2S and Na2SO3 as sacrificial reagents in water under visible-light illumination (λ ≥ 420 nm). The most important aspect of this work is the use of natural products (VMT) as host photocatalysts. The effect of CdS content on the rate of visible light photocatalytic hydrogen generation was investigated for different CdS loadings. The synergistic effect of VMT and CdS quantum dots (QDs) leads to efficient separation of the photogenerated charge carriers and, consequently, enhances the visible light photocatalytic hydrogen production activity of the photocatalyst. The CdS/VMT composite with an optimal ratio of 5% exhibits the highest hydrogen evolution rate of 92 μmol h(-1) under visible light irradiation and the highest apparent quantum efficiency of 17.7% at 420 nm. A possible photocatalytic mechanism of the CdS/VMT nanocomposite is proposed and corroborated by photoelectrochemical curves.

Study of Hybrid Photovoltaic Materials with Poly(3-Hexylthiophene) and CdS Nanoparticles by Spectroscopic Techniques

Poly (3-hexylthiophene) (P3HT) was synthesized via chemical oxidative reaction at room temperature with anhydrous ferric chloride as oxidant. The hybrid films of P3HT were prepared by doping inorganic semiconductor nanoparticles of CdS. Fourier transform infrared (FT-IR) spectrum, UV-vis, fluorescence and resonance light scattering (RLS) spectra were applied to characterize the photophysical properties of P3HT and doped polymer. The results indicated that the infrared absorbance of hybrid films increased with the increase of doped CdS content. The intensity of UV absorption presented a slight increase, the blend spectra were simply the sum of the absorptions of the constituent parts of the composite solution. With the addition of CdS nanoparticles, the emission peak of P3HT was shifted to longer wavelengths. The shift from 543 to 567 nm was due to the fluorescence resonance energy transfer between CdS nanoparticles and P3HT, and then the red-shift from 567 to 573 nm was caused by the agglomeration of CdS nanoparticles. RLS spectra revealed that the maximum scattering wavelength of systems initially showed a blue-shift, and then exhibited a pronounced red-shift with the addition of CdS nanoparticles. These findings provided insights into the role of spectroscopic techniques in studying the photophysical properties of composites. Our further work is toward investigating the mechanism and dynamic process of exciton interaction between polymers and inorganic semiconductor nanoparticles.

Synthesis of uniform ZnO/ZnS/CdS nanorod films with ion-exchange approach and photoelectrochemical performances

The uniform ZnO/ZnS/CdS core–shell nanorod film was synthesized by a two-step ion-exchange method. The crystal structure, morphology, composition and optical property of as-prepared films were characterized by X-ray diffraction (XRD), Raman, Scanning electron microscope (SEM), Transmission electron microscope (TEM), Energy dispersive X-ray Detector (EDX) and UV–vis techniques. The results showed that the ZnO nanorod arrays can be used as sacrificial templates to synthesize uniform ZnS layer and further transform into CdS by simple ion-exchange approach. The CdS content in the films can be adjusted easily by changing the reaction temperature. The intimate contact between core and shell can be observed by high-resolution TEM image, which decrease the crystal boundary potential barrier and then facilitate the photogenerated charges transfer between the different phases. In this experiment, the ZnO/ZnS/CdS nanorod films were used in the photoelectrochemical (PEC) hydrogen production. And it is found that the film prepared at 70 °C (first step) and 100 °C (second step) gives a maximum photocurrent density and photo conversion efficiency.

Controllable preparation and optical limiting properties of CdS nanocomposites in KGM-AA soft template

Konjac glucomannan acrylates (KGM-AA) were used as soft templates to prepare the CdS nanoparticles. The structure and properties of the CdS nanoparticles were characterized and evaluated with XRD, TEM, HRTEM, TGA, UV–vis, Raman spectrum, optical limiting and nonlinear optical analyses (Z-scan technique), respectively. It was interesting to find that nanosized CdS particles successfully grew in situ and uniformly dispersed in the KGM-AA soft templates and their size and density could be effectively controlled by varying the feed ratio of Cd2+/KGM-AA. When the feed ratio is up to 17.47% (wt%), the material exhibits the best optical limiting performance with limiting threshold of 367mJ/cm2, and good nonlinear optical properties with nonlinear absorption coefficient (α2) of 6.6023×10−10cmW−1 and nonlinear refractive index (n2) of 1.27×10−4cm2/GW. The optical limiting performances increase with the increase of CdS content in the composites. The optical limiting mechanism is mainly originated from the self-focusing behavior of CdS nanoparticles.

Preparation of CdS–TiO2/Fe3O4 photocatalyst and its photocatalytic properties

The CdS modified TiO2/Fe3O4 photocatalysts were prepared by sol–gel and immersion methods. The morphological, structural and optical properties of as-prepared samples were characterized by X-ray diffraction (XRD), UV–Vis absorption spectra, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The TEM observation showed that the surface of magnetite particles (Fe3O4) were coated by CdS–TiO2 layer as loose clusters, and average diameter of composites particles was about 250 nm. UV–Vis absorption spectra indicated that CdS–TiO2/Fe3O4 composites had pronounced red-shift compared with that of TiO2/Fe3O4. The CdS–TiO2/Fe3O4 composites exhibit higher photocatalytic activity than pure TiO2 and TiO2/Fe3O4 for the degradation of Reactive Brilliant Red X-3B dye (X-3B) aqueous solution under simulated sunlight, and the optimum content of CdS is 1.0 % (mol ratio of CdS to TiO2). In addition, a gradual loss of photocatalytic activity can be observed in reusability test of CdS–TiO2/Fe3O4 composites, and degradation of X-3B reached still to 78.9 % after five runs.

Optical spectroscopy of thin C60:CdS composite films

The fabrication procedure, structure, and optical spectroscopy data for thin composite films based on a fullerene material with a 0.5–10% cadmium-sulfide impurity content are reported. The technology for producing structures with a composition gradient in a single vacuum cycle is developed. The samples are studied by atomic-force microscopy, Raman spectroscopy, and photoluminescence measurements. At the optimal CdS content, charge transfer to fullerene molecules is observed. This effect is apparently responsible for the zero-barrier polymerization of the films. In the photoluminescence spectra of the composite films, a 0.09–0.11 eV shift of the peak to shorter wavelengths and an increase in the photoluminescence intensity in comparison to the photoluminescence peak position and intensity in pure fullerene samples are detected. The composite structures with a CdS-content gradient through their thickness exhibit rectifying current-voltage characteristics.

Electrochemically Grown ZnO Nanorod Arrays Decorated with CdS Quantum Dots by Using a Spin-Coating Assisted Successive-Ionic-Layer-Adsorption and Reaction Method for Solar Cell Applications

CdS quantum dots (QDs) decorated ZnO nanorod (NR) arrays were fabricated by a two-step method. The first step consisted in electrochemical growth of single-crystalline ZnO NR arrays, followed by the novel spin-coating assisted SILAR method for decorating the ZnO NRs with CdS QDs. Structural, morphological and optical characterization of CdS QDs/ZnO NR arrays were done. ZnO NRs had a single crystal wurtzite structure growing along the c-axis. The decorated CdS QDs had a quasi-spherical shape with a mean diameter of about 5 nm. The increase of CdS content produces an increase in the visible part of the absorption spectrum. Bandgap energy values for ZnO between 3.26–3.29 eV were obtained. For CdS the measured absorption edge values are between 2.35–2.65 eV (decreasing with the number of coating cycles). Numerical simulations based on effective medium approximation were done to verify these features. The Urbach tail parameter in CdS absorption edge is between 44–52 meV. The photovoltaic performance of ZnO and CdS QDs/ZnO NRs have been evaluated in a photoelectrochemical solar cell configuration with a polysulfide electrolyte under white illumination. The decoration of ZnO NRs with CdS QDs leads to a cell performance of JSC = 2.67 mA/cm2, VOC = 0.74 V, FF = 0.30 and η = 1.48%.

Hierarchically grown CdS/α-Fe2O3 heterojunction nanocomposites with enhanced visible-light-driven photocatalytic performance

Wide spectral responsive 3D hierarchical CdS/α-Fe2O3 heterojunction nanocomposites were synthesized through a facile chemical bath method under mild conditions, and used for the reduction of Cr(VI) into Cr(III) under visible light irradiation. The effects of CdS/α-Fe2O3 molar ratio in the nanocomposites on the crystal phases, microstructures, optical absorption properties, and photocatalytic reduction of Cr(VI) were investigated comparatively. It was found that the as-synthesized CdS/α-Fe2O3 nanocomposites with a suitable CdS content (e.g., the molar ratio of Fe : Cd = 1.25 : 3) had not only high visible-light-driven photocatalytic activity in the Cr(VI) reduction, but also good photocatalytic stability. The enhanced photocatalytic activity can be ascribed to some CdS nanoparticles closely contacting the α-Fe2O3 microflowers to form a heterojunction structure. These tight heterojunctions of the photocatalysts result in an efficient electron-hole pairs separation at the interface, followed by fast diffusion of photogenerated charge between CdS and α-Fe2O3, which is beneficial for separating the photogenerated carriers in space and improving the photocatalytic activity.

Comparative study of ML and PL spectra of different impurity-doped (Zn, Cd)S mixed phosphors

This paper reports the mechanoluminescence (ML) and photoluminescence (PL) spectra of (Zn, Cd)S:Mn, (Zn, Cd)S:Cu, (Zn, Cd)S:Ag, and (Zn, Cd)S:Au mixed phosphors. The PL spectra of the phosphors were similar to the ML spectra within the limit of experimental error. For (Zn, Cd)S:Cu, (Zn, Cd)S:Ag, and (Zn, Cd)S:Au phosphors ML spectra shifted toward lower wavelength compared with PL spectra whereas for the Mn-doped (Zn, Cd)S phosphor ML spectra shifted toward higher wavelength compared with PL spectra. ML and PL spectra of doped (Zn, Cd)S mixed phosphors shifted toward longer wavelength with increasing CdS content.

Synthesis and Efficient Visible Light Photocatalytic Hydrogen Evolution of Polymeric g-C3N4 Coupled with CdS Quantum Dots

Novel CdS quantum dot (QD)-coupled graphitic carbon nitride (g-C3N4) photocatalysts were synthesized via a chemical impregnation method and characterized by X-ray diffraction, transmission electron microscopy, ultraviolet–visible diffuse reflection spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and photoluminescence spectroscopy. The effect of CdS content on the rate of visible light photocatalytic hydrogen evolution was investigated for different CdS loadings using platinum as a cocatalyst in methanol aqueous solutions. The synergistic effect of g-C3N4 and CdS QDs leads to efficient separation of the photogenerated charge carriers and, consequently, enhances the visible light photocatalytic H2 production activity of the materials. The optimal CdS QD content is determined to be 30 wt %, and the corresponding H2 evolution rate was 17.27 μmol·h–1 under visible light irradiation, ∼9 times that of pure g-C3N4. A possible photocatalytic mechanism of the CdS/g-C3N4 comp...

Microstructural, optical and photocatalytic properties of CdS doped TiO2 thin films

CdS doped TiO2 thin films (with CdS content=0, 3, 6, 9 and 12at%) were grown on glass substrates. The X-ray diffraction analysis revealed that the films are polycrystalline of monoclinic TiO2 structure. The microstructure parameters of the films such as crystallite size (Dν) and microstrain (e) are calculated. Both the crystallites size and the microstrain are decreased with increasing CdS content. The optical constants have been determined in terms of Murmann's exact equations. The refractive index and extinction coefficient are increased with increasing CdS content. The optical band gap is calculated in the strong absorption region. The possible optical transition in these films is found to be an allowed direct transition. The values of Egopt are found to decrease as the CdS content increased. The films with 3at% CdS content have better decomposition efficiency than undoped TiO2. The films with 6at% and 9at% CdS content have decomposition efficiency comparable to that of undoped TiO2, although they have lower band gap. The CdS doped TiO2 could have a better impact on the decomposing of organic wastes.

Photocatalytic activity of TiO2 sensitized by CdS quantum dots under visible-light irradiation

In this paper, CdS quantum dots sensitized TiO2 composite powders (QD-CdS/TiO2) were synthesized by impregnating TiO2 powder into CdS sol with different concentrations. X-ray diffraction pattern (XRD) shows the crystal structures of CdS and TiO2 are cubic phase and anatase phase separately in QD-CdS/TiO2 powder samples; the crystal size of CdS in QD-CdS/TiO2 is about 3–7 nm, while TiO2 crystal size is about 20 nm. With increasing CdS content in QD-CdS/TiO2 composite, the UV-Vis absorption spectrum shifted to the longer wavelength lines, exhibiting obvious quantum size effect. The fluorescence intensity of QD-CdS/TiO2 irradiated by blue light is weaker than that of pure CdS. When the molar ratio of CdS and TiO2 is about 1:2, the QD-CdS/TiO2 powder has the best catalytic properties under visible-light irradiation, and the degradation rate of rhodamine B (RhB) is up to 92.2% within 60 min.

Effect of CdS contents on H2 production from Pt-(CdS/TiO2) film-typed photocatalysts

Pt-(CdS/TiO2) film-typed photocatalysts are prepared with a doctor-blade method followed by a chemical bath deposition (CBD) process, and the films are characterized by UV-vis spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy. The film-typed structure is composed of photocatalysts and Pt metal part on a FTO substrate without additional electric device, so it is relatively simpler than the conventional photoelectrochemical cell. CdS quantum dots are introduced as a sensitizer for visible light response. Amounts of CdS quantum dots on TiO2 surface are increased with increasing CBD cycles, but they start to aggregate after certain CdS concentration due to oversaturation phenomenon. This high CdS content induces high electron losses, and therefore it reduces amounts of hydrogen production. As a result, there is a saturation point of CdS content at Cd/Ti ratio of 0.197, and the amounts of evolved hydrogen are 5.407 μmol/cm2·h at this photocatalyst formulation.

Sonocatalytic degradation of Rhodamine B in the presence of C 60 and CdS coupled TiO 2 particles

CdS-TiO 2 and CdS-C 60/TiO 2 were prepared using C 60, cadmium acetate dehydrate [(CH 3COO) 2Cd·2H 2O], sodium sulfide (Na 2S·5H 2O) and titanium (IV) n-butoxide by a sol–gel method. The prepared sonocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and transmission electron microscopy (TEM). A rhodamine B (RhB) solution under ultrasonic irradiation was used to determine the catalytic activity. Excellent catalytic degradation of an RhB solution was observed using the CdS-C 60/TiO 2 composites under ultrasonic irradiation. C 60 coupled CdS-TiO 2 can enhance the Brunauer–Emmett–Teller (BET) surface area and increase the decolorization rate for rhodamine B solution. The results also shows that increase the content of CdS can enhance the catalytic activity.

Preparation and Second Harmonic Generation of CdS Doped Lead Silicate Glasses

CdS doped lead silicate glasses were prepared with the conventional fusion method. The effects of the ZnO/CdS ratio and the content of CdS on the preparation of CdS doped glasses were both studied. The crystallization process of CdS nanocrystals was investigated by X-ray diffractometry and scanning electron microscopy. Utilizing the Maker fringe method, Second harmonic generation (SHG) was observed from CdS doped glasses without any poling procedures. The SH intensity gets enhanced by increasing the heat-treatment temperature and prolonging the heat-treatment duration.