CdS Nanoparticles Research Articles

Synthesis, structure, and optical studies of nanocomposites based on copoly (arylidene cyclohexanone) and CdS nanoparticles for photocatalytic and white LED applications

For various optical applications, the fabrication of nanocomposites of co-polyarylidene (cyclohexanone/4-tertiary butyl cyclohexanone) CoP6 with various-sized cadmium sulfide CdS nanoparticles via in situ polymerization has been investigated (CoP6-CdS NCs). Several techniques like FT-IR, XRD, XPS, SEM, TGA, TEM, UV–vis, and fluorescence emission have been used to investigate, characterize, and study nanocomposites' structural and optical characteristics. The optical band gap of NCs was found to have a slight redshift, from 2.81 to 2.71 eV, with no alteration to the absorption peak. The crystallinity and phase formation were studied by XRD, which showed that the produced NCs with larger (CdS) particles retain some crystalline structure. The NCs generated were characterized by SEM and TEM, revealing their aggregation inside the polymer matrix. The thermal stability of the produced nanocomposites varies with the size of the nanoparticles, with larger NPs being less stable than CoP6 in the first two stages of thermal degradation and smaller NPs showing better stability in the first stages. Their outstanding optical properties make them be used in solar cells and photocatalysts. According to the photophysical analysis, new CoP6-CdS NCs have excellent optical quality with 95% optical transparency and low absorption in the visible region; the light transmittance in the UV region is reduced as the size of the CdS NP increases. There is a potential for using CoP6-CdS NCs in white LED applications in the visible region by varying CdS nanofiller size. However, because the nanocomposites exhibit enhanced absorption in the UV region, they can be used as a material for UV protection.

CdS-assisted ultrathin porous nitrogen-vacancy carbon nitride nanosheets for visible-light photocatalytic CO2 reduction

Obtaining highly active and selective target products is both promising and challenging, and can be achieved by regulating the adsorption and desorption energy of reaction intermediates, as well as the transfer of electrons under visible light. Herein, an efficient CNGA/CdS photocatalyst based on ultrathin porous nitrogen vacancies carbon nitride (CNGA) nanosheets (thickness <1 nm) with CdS nanoparticles was synthesized by a facile route for visible-light photocatalytic CO2 reduction. As a result, the rate of CO production was 32.75 μmol g−1 h−1, which was 17.24 and 32.75 times that of CN and CdS under visible light (λ ≥ 420 nm) without sacrificial agents and cocatalysts. Importantly, introducing CdS nanoparticles into CNGA could improve the selectivity of CO2 to CO by nearly 100% (yield-based selectivity). Finally, the photocatalytic mechanism was explored by in-situ FTIR spectra and DFT calculations, and the results presented that the formation of heterostructures facilitated the generated *CO groups to modulate the reaction pathway of photocatalytic CO2 reduction. This work is expected provide a reference for the design of photocatalysts for photoreduction CO2 with accurate products under visible light.

Li sensitized CdS/TiO2 nanocomposite photoanode for solar water splitting, hydrogen generation and photoelectrochemical (PEC) performance

Li–CdS/TiO2 nanocomposite with different composition 10Li–CdS/TiO2, 20Li–CdS/TiO2, 30Li–CdS/TiO2, 40Li–CdS/TiO2, 50Li–CdS/TiO2 were coated on FTO surface by using doctor blade followed by successive ionic layer adsorption and reaction (SILAR) method. As synthesized Li–CdS/TiO2 photoanode is characterized with field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), high resolution transmission electron microscopy (HR-TEM), diffuse reflectance spectroscopy (UV-DRS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL). FE-SEM analysis suggests that, Li–CdS/TiO2 film is 10.2 μm thick, porous, spongy and uniformly covered on FTO surface. The HR-TEM images reveal that the CdS nanoparticles are in intimate contact with the TiO2 nanocrystal shells with the CdS/TiO2 interfaces and the particle size of CdS and Li2S lies in the range of 20 nm–50 nm. UV-DRS analysis shows that, as the loading of Li in CdS/TiO2 films increases, there is decrease in band gap energy. The XPS analysis supports the presence of Li+ in Li–CdS/TiO2 nanocomposite. The PL spectra suggest that, with the increase in extend of Li+ ions into Li–CdS/TiO2, intensity of green emission band increases and it is shifted to higher wavelength. This reflects the low recombination rate of photo generated charge carrier in Li–CdS/TiO2 which is responsible for higher photocatalytic H2 production. The visible light photoanodic performance of Li–CdS/TiO2 was investigated for H2 evolution using aqueous Na2SO3 and Na2S solution under natural sunlight. Among the all-synthesized nanocomposite material, the highest amount of hydrogen produced over 20Li–CdS/TiO2 was found to be 38.61 ml/g/h in natural sunlight. Photoelectrochemical (PEC) performance of Li–CdS/TiO2 was examined. A possible mechanism for photocatalytic hydrogen generation is also discussed.

Simultaneous benzyl alcohol oxidation and H2 generation over MOF/CdS S-scheme photocatalysts and mechanism study

The conversion from solar energy into storable chemical energy can be achieved through synergistic coupling of photocatalytic H2 production and organic synthesis, during which photogenerated electrons and holes can be simultaneously utilized. Herein, we combined a zirconium-based metal-organic framework, UiO-66-NH2, and CdS nanoparticles (NPs) to form a core-shell structure by a chemical bath method. The step-scheme (S-scheme) heterojunction exhibits both substantially enhanced selective oxidation of benzyl alcohol and efficient H2 generation under light irradiation simultaneously. The electron transfer paths at the S-scheme heterostructure interface were investigated in depth by in situ irradiated X-ray photoelectron spectroscopy. The dynamics of carrier migration at the heterojunction were obtained through femtosecond transient absorption (fs-TA) spectroscopy. Furthermore, the evolution mechanism of benzaldehyde was revealed by in situ diffuse reflectance infrared Fourier transform spectroscopy and electron paramagnetic resonance. This work illustrates the electron transfer mechanism of S-scheme heterojunction by fs-TA spectroscopy and provides new insights into the design of MOF/inorganic composite photocatalysts.

Solution Processed Highly Efficient H2S Gas Sensor With Sub-ppb Detection Limit Based on Self-Aligned Thin Film of PCPDTBT Decorated With CdS Nanoparticles

Solution Processed Highly Efficient H₂S Gas Sensor With Sub-ppb Detection Limit Based on Self-Aligned Thin Film of PCPDTBT Decorated With CdS Nanoparticles

Significantly enhanced photocatalytic hydrogen production performance of MoS2/CNTs/CdS with carbon nanotubes as the charge mediators

Photocatalysis technology can efficiently produce hydrogen, which is essential for the sustainable development of clean energy. Herein, molybdenum sulfide/carbon nanotubes/cadmium sulfide (MoS2/CNTs/CdS) ternary composites are designed as catalysts to obtain an efficient photocatalytic hydrogen production system. In particular, the in-situ growth of CdS on the surface of MoS2/CNTs improves the dispersion of CdS nanoparticles, reduces the size of CdS particles, and increases the active site of photocatalytic reaction. A built-in electric field is formed between the interface between CdS and MoS2, which causes photogenerated electrons in conduction band (CB) of CdS and photogenerated holes in valence band (VB) of MoS2 to move in Z-type conduction mechanism. The excellent charge-conducting ability of CNTs reduces the recombination of photogenerated electrons and holes in CdS, further improving the hydrogen production efficiency and the stability of photocatalytic performance. Experiments showed that MoS2/CNTs/CdS (15%) have the highest hydrogen production rate (101.18 mmol h−1 g−1), which was 253 times higher than that of pure CdS. This study is expected to provide new ideas for the design and preparation of ternary hybrid photocatalysts for hydrogen production by photolysis of water.

Nanoconfinement dynamics and crystal plane exposure: Synergistic promotion of simulated solar-driven H2O-to-H2 conversion on host (CdS)-guest (Ti single-atom) nano-photocatalyst

Hexagonal cadmium sulfide (h-CdS) is very prospective in photocatalytic hydrogen production due to its appropriate band structure, and researchers concern so much on the morphological characteristics of nanoparticles (NPs) and nanorods (NRs). Due to different dimensions of two forms of nanostructures, very different nanoconfinement (NF) characteristics are presented, leading to different separation and migration kinetics of photoexcitons, thereby showing different catalytic performance. However, the inherent mechanism is still ambiguous, and this NF effect extensively exists in photocatalytic process, even determining the final catalytic performance. Herein, CdS NPs and CdS NRs here were synthesized and decorated by single-atomic titanium (Ti SAs) to construct two forms of nanoconfined systems with host (CdS)-guest (Ti) (H-G) interaction. Due to the typical three-dimensional (3D) NF dynamics of CdS NPs, the H-G interaction of optimized CdS NPs-Ti nanocatalyst played an isotropic synergistic dynamics on body-to-surface (BTS) photoexcitons migration, dramatically suppressing their recombination behaviors, thereby achieving more considerable improvement of simulated sunlight (SSL)-driven HER photoactivity (14.10 mmol·h−1·g−1, 22.5-fold of CdS NPs, AQY400 nm = 20.44%), and outperforming many non-precious metal and precious metal modified CdS nanocatalysts under same experimental conditions. Surface transient photovoltage (TPV) and first-principle calculations revealed that the appropriate crystal plane exposure and typical 3D NF dynamics of CdS NPs highly benefits to the formation of Ti-S bonding interactions followed by the isotropic H-G synergistic dynamics, possessing more boosted BTS migration kinetics of photoexcitons followed by highly suppressed recombination kinetics, thereby acquiring higher solar-to-hydrogen (STH) conversion efficiency. This study provides a prospective insight for elucidating an observable NF dynamics of photoexcitons.

CdS Nanoparticles Supported by Cobalt@Carbon-Derived MOFs for the Improved Adsorption and Photodegradation of Ciprofloxacin.

The design and synthesis of efficient photocatalysts that promote the degradation of organic pollutants in water have attracted extensive attention in recent years. In this work, CdS nanoparticles are grown in situ on Co@C derived from metal-organic frameworks. The resulting hierarchical CdS/Co@C nanostructures are evaluated in terms of their adsorption and photocatalytic ciprofloxacin degradation efficiency under visible-light irradiation. The results show that, apart from offering a large surface area (55.69 m2·g-1), the prepared material can effectively suppress the self-agglomeration of CdS and enhance the absorption of visible light. The CdS/Co@C-7 composite containing 7% wt Co@C has the highest photodegradation rate, and its activity is approximately 4.4 times greater than that of CdS alone. Moreover, this composite exhibits remarkable stability after three successive cycles of photocatalysis. The enhanced photocatalytic performance is largely ascribed to the rapid separation of electron-hole pairs and the effective electron transfer between CdS and Co@C, which is confirmed via electrochemical experiments and photoluminescence spectra. The active substance capture experiment and the electron spin resonance technique show that h+ is the main active entity implicated in the degradation of CIP, and accordingly, a possible mechanism of CIP photocatalytic degradation over CdS/Co@C is proposed. In general, this work presents a new perspective on designing novel photocatalysts that promote the degradation of organic pollutants in water.

Effect of Eu3+ doping on structural, optical and magnetic characteristics of doped CdS nanoparticles

Hydrothermal method has been used to synthesize Cd1-xEuxS (x = 0, 0.01, 0.02 and 0.03) nanoparticles. With Eu-doping the changes in optical, magnetic and structural properties has been confirmed by UV–visible spectroscopy, PL, VSM and XRD. The X-ray diffraction confirmed wurtzite phase and peak shifting towards higher diffraction angle with Eu-doping can be ascribed to the smaller Eu3+ ion as compared to that of Cd2+ ion. The band gap enhances varying from 2.44 eV to 2.52 eV. The magnetic study proved the presence of ferromagnetism in both the samples i.e. undoped and doped synthesized nanoparticles with increment in magnetization. This study proposes that both the optical band gap and magnetic behavior shall be improved by suitable Eu-doping.

Fluorescence Study of Pr3+ Doped CdS Nanoparticles and its Applications in Sensors and Detectors.

Fluorescence spectra of Pr3+ doped CdS nanoparticles, synthesized by chemical precipitation method, have been recorded at room temperature. The synthesized particles are nearly spherical shaped and the grain size is decreased with the increase in Pr3+ concentration. The chemical identity of the nanoparticles was confirmed by EDAX spectrum, the absorption peaks was confirmed by FTIR spectrum and then the recorded values were compared with the CIE diagram. The oscillator strengths of the 4f ↔ 4I transitions are parameterized in terms of three phenomenological Judd-Ofelt intensity parameters Ωλ (λ = 2, 4 and 6). Using the fluorescence data and these Ωλ parameters, theoretical and experimental study of various radiative properties viz., spontaneous emission probability (A), radiative life time , fluorescence branching ratio and stimulated emission cross-section were evaluated. The values of these parameters indicate that 3P0→ 3H4 transition can be considered to be good laser transition in the visible colour region. Also, excitation with 493 nm, leads to similar blue regions. The synthesized Pr3+ doped CdS nanomaterials could be useful for sensing and detecting devices, particularly for temperature sensing measurement and bio-sensing detection.

A competitive photoelectrochemical sensor based on the in situ formation of BiOBr/Bi2S3 by Cs3Bi2Br9 for the detection of trenbolone

This work for the first time proposed a photoelectrochemical (PEC) sensor based on the in situ generation of BiOBr/Bi2S3 by Cs3Bi2Br9 to detect trenbolone (TB). To be specific, Cs3Bi2Br9/BiOBr/Bi2S3 heterojunction, the chosen photoelectric material, that could produce stable and large photocurrent was obtained through two steps in situ growth method on the basic of Cs3Bi2Br9 perovskite. CdS and Au nanoparticles with outstanding light absorption characteristics were selected as TB antigen (Ag) marker. Under the aid of Au/CdS, the association between TB concentration and output current will be revealed by the competitive combining of TB antibodies (Ab) with TB or Ag-Au/CdS. If the concentration of TB was lower, the more Ag-Au/CdS was connected to the Ab, and the higher photocurrent signal was obtained. Hence, the competitive PEC sensor could realize reliable detection of TB with a lower detection limit of 29.7 fg mL-1.

Enhancing the photocatalytic efficiency of CdS nanostructures by ZnS: A case study on the degradation of methylene blue

Removal of toxic organic industrial dye affluents using solar energy is a sustainable means for overcoming the current energy crisis as well as environmental hazards. CdS nanoparticles are promising photocatalysts due to their energy gap of 2.42 eV and high specific area. Surrounding the CdS core with a shell of ZnS has the potential of reducing the recombination of electron-hole pairs and hence increase its photocatalytic activity. We report here the enhanced photocatalytic activity of CdS/ZnS nanoparticles for the degradation of Methylene blue (MB). The adsorption of MB on the nanoparticles is found to obey pseudo-second-order kinetics.

Sıvı kristaller ve nanopartikül arasındaki etkileşimlerin belirlenmesi üzerine çalışma: Nanopartikül katkılı sıvı kristallerin floresan spektrumları

Liquid crystals, which are between the solid state of matter and the liquid state, are materials with interesting molecular structures. They are molecular materials that show both the properties of solid crystals and the properties of liquids. Materials whose physical properties change depending on the particle size, whose dimensions are at the nanometer level, are nanoparticles. Nanoparticles can be produced in many different types, depending on their size and structural shape. We obtained fluorescence graphs by combining liquid crystals and nanoparticles in solvents with three different characteristics. The liquid crystals we used in this study are 4-Pentylphenyl 4-Methoxybenzoate (4PP4MetoxB), 4-Pentylphenyl 4-Pentylbenzote (4PP4PentB), and 4-Pentylphenyl 4-(Octyloxy)Benzoate (4PP4OctoxB). Other materials we use are ZnS, CdSe, and CdS nanoparticles. We created new materials by combining these liquid crystals and nanoparticles in solvents. We examined whether the liquid crystals and nanoparticles in the newly formed materials interact in solvents and how the fluorescence graphs change according to the fluorescence graphs of liquid crystals.

Heterostructured CdS Buffer Layer for Sb2Se3 Thin Film Solar Cell

The antimony selenide thin film solar cells technology becomes promising due to its excellent anisotropic charge transport and brilliant light absorption capability. Especially, the device performance heavily relies on the vertically oriented Sb2Se3 grain to promote photoexcited carrier transport. However, crystalline orientation control has been a major issue in Sb2Se3 thin film solar cells. Herein, a new strategy has been developed to tailor the crystal growth of Sb2Se3 ribbons perpendicular to the substrate by using the structural heterostructured CdS buffer layer. The heterostructured CdS buffer layer is formed by a dual layer of CdS nanorods and nanoparticles. The hexagonal CdS nanorods passivated by a thin cubic CdS nanoparticle layer can promote [211] and [221] directional growth of Sb2Se3 ribbons using a close space sublimation approach. The improved buffer/absorber interface, reduced interface defects, and recombination loss contribute to the improved device efficiency of 7.16%. This new structural heterostructured CdS buffer layer can regulate Sb2Se3 nanoribbons crystal growth and pave the way to further improve the low‐dimensional chalcogenide thin film solar cell efficiency.

Construction of a transition-metal sulfide heterojunction photocatalyst driven by a built-in electric field for efficient hydrogen evolution under visible light

Photocatalytic H2 evolution is of prime importance in the energy crisis and in lessening environmental pollution. Adopting a single semiconductor as a photocatalyst remains a formidable challenge. However, the construction of an S-scheme heterojunction is a promising method for efficient water splitting. In this work, CdS nanoparticles were loaded onto NiS nanosheets to form CdS/NiS nanocomposites using hollow Ni(OH)2 as a precursor. The differences in the Fermi energy levels between the two components of CdS and NiS resulted in the formation of a built-in electric field in the nanocomposite. Density functional theory (DFT) calculations reveal that the S-scheme charge transfer driven by the built-in electric field can accelerate the effective separation of photogenerated carriers, which is conducive to efficient photocatalytic hydrogen evolution. The hydrogen evolution rate of the optimized photocatalyst is 39.68 mmol·g−1 h−1, which is 6.69 times that of CdS under visible light. This work provides a novel strategy to construct effective photocatalysts to relieve the environmental and energy crisis.

Size-dependent solvatochromism of CdS nanoparticles: Experimental absorption and fluorescence analyses

Owing to the quantum confinement effect, a nanocrystal shows a unique blend of molecular and solid properties: discrete energy levels with large polarizabilities which could respond to solvent environments. In this paper, we used steady-state fluorescence and absorption spectroscopy to study the size-dependent solvatochromism of CdS nanoparticles. The dipolar character of the ground state and the first excited state of the nanoparticle were also investigated with in the framework of Onsager reaction field theory using Ooshika–Mataga–Lippert equation. The results of the present study revealed that the solvatochromic responses were size dependent. Additionally, the responses increased with the particle size up to a certain size beyond which the response started to fall again. Hence, fine-tuning the nanoparticle's solvatochromic response and band gap is possible by appropriate choice of size. Moreover, size-dependent dipole moment values of CdS nanoparticles were determined. Based on the findings of the present study it was noted that steady-state fluorescence and absorption spectroscopy methods can efficiently be used to study the size-dependent solvatochromism of CdS nanoparticles.

Photocatalytic, Antibacterial, Cytotoxic and Bioimaging Applications of Fluorescent CdS Nanoparticles Prepared in DNA Biotemplate.

Synthesizing nanoparticles in biotemplates has been cited as one of the most promising way to obtain monodispersed inorganic nanoparticles. In this method, uniform voids in porous materials serve as hosts to confine the synthesized nanoparticles. DNA template can be described as a smart glue for assembling nanoscale building blocks. Here we investigate the photocatalytic, antibacterial, cytotoxic, and bioimaging applications of DNA capped CdS. XRD, SEM, TEM, UV-visible absorption, and photoluminescence spectra were used to study structural, morphological, and optical properties of CdS nanoparticles. Prepared CdS nanoparticles exhibit visible fluorescence. The photocatalytic activity of CdS towards Rhodamine 6G and Methylene blue are 64% and 91% respectively. A disc-diffusion method is used to demonstrate antibacterial screening. It was shown that CdS nanoparticles inhibit Gram-positive bacteria and Gram-negative bacteria effectively.DNA capped CdS shows higher activity than uncapped CdS nanoparticles. MTT cell viability assays were carried out in HeLa cells to investigate the cytotoxicity for 24h. At a concentration 2.5µg/ml, it shows 84% cell viability and 43% viability at12.5µg/ml. The calculated LC50 value is equal to 8µg/ml. These DNA capped CdS nanoparticles were taken for an in-vitro experiment with HeLa cells to exhibit the possibility of bioimaging applications. The present study suggests that the synthesized CdS nanoparticles could be a potential photocatalyst, antibacterial agent, and biocompatible nanoparticle for bioimaging applications.

Construction of Ag/Ag2S/CdS Heterostructures through a Facile Two-Step Wet Chemical Process for Efficient Photocatalytic Hydrogen Production

We have demonstrated a two-step wet chemical approach for synthesizing ternary Ag/Ag2S/CdS heterostructures for efficient photocatalytic hydrogen evolution. The CdS precursor concentrations and reaction temperatures are crucial in determining the efficiency of photocatalytic water splitting under visible light excitation. In addition, the effect of operational parameters (such as the pH value, sacrificial reagents, reusability, water bases, and light sources) on the photocatalytic hydrogen production of Ag/Ag2S/CdS heterostructures was investigated. As a result, Ag/Ag2S/CdS heterostructures exhibited a 3.1-fold enhancement in photocatalytic activities compared to bare CdS nanoparticles. Furthermore, the combination of Ag, Ag2S, and CdS can significantly enhance light absorption and facilitate the separation and transport of photogenerated carriers through the surface plasma resonance (SPR) effect. Furthermore, the Ag/Ag2S/CdS heterostructures in seawater exhibited a pH value approximately 2.09 times higher than in de-ionized water without an adjusted pH value under visible light excitation. The ternary Ag/Ag2S/CdS heterostructures provide new potential for designing efficient and stable photocatalysts for photocatalytic hydrogen evolution.

ФОРМУВАННЯ ТА ВЛАСТИВОСТІ СТРУКТУРОВАНИХ ПОЛІАКРИЛАМІДНИХ ГІДРОГЕЛІВ З НАНОЧАСТИНКАМИ CdS

The new method of obtaining nanocomposite hydrogels with embedded mineral nanoparticles has been proposed. CdS nanoparticles have been synthesized in situ in hydrogel matrix based on the copolymer of acrylamide and acrylic acid under the conditions of diffusion fluxes of Cd2+ та S2- structure-forming ions. The formation of CdS nanoparticles in polymeric matrix has been approved by the methods of XRD, energy- dispersive analysis, UV-spectroscopy. The influence of the content of polymer matrix onto physico- mechanical properties of hydrogel has been studied.

CdS decorated resorcinol–formaldehyde spheres as an inorganic/organic S-scheme photocatalyst for enhanced H2O2 production

Photocatalytic H2O2 production provides a clean and sustainable strategy for artificial photosynthesis. Herein, an inorganic/organic composite photocatalyst was fabricated by in-situ growth of CdS nanoparticles on the surface of resorcinol–formaldehyde (RF) resin spheres. RF spheres played multiple roles: (i) acting as a substrate for the growth of CdS and constructing a core-shell structure with seamless contact; (ⅱ) improving visible light absorption of CdS; (ⅲ) forming an S-scheme heterojunction with CdS and promoting the charge separation and transfer. Consequently, under visible light illumination, CdS/RF composite presented remarkably enhanced H2O2 production activity. Its H2O2 yield in 60 min was 801 μmol L–1, which was 5.2 and 1.5 times higher than that of RF spheres and CdS hollow spheres, respectively. The charge migration between CdS and RF followed the S-scheme photocatalytic mechanism, which was verified by work function measurement, ex-situ and in-situ irradiated X-ray photoelectron spectroscopy. This work brings a novel insight into designing RF-based inorganic/organic S-scheme heterojunction photocatalysts for efficient H2O2 production.