Cadmium Sulfide Nanorods Research Articles

Construction of Z–scheme 1D CdS nanorods/2D ultrathin CeO2 nanosheets toward enhanced photodegradation and hydrogen evolution

The synthesis of semiconductor-based photocatalytic materials has been developed rapidly because of the wide application potential in solving environmental pollution and energy crises. In this study, a noval Z–scheme heterojunction by in situ assembly of two-dimensional (2D) ceria nanosheets and one-dimensional (1D) cadmium sulfide nanorods (CdS/CeO2) was constructed and employed for effective photocatalytic degradation of contaminant and hydrogen production under irradiation. The morphologies and physicochemical properties of as-synthesized nanostructures were analyzed by a series of characterizations. The optimized CdS/CeO2 showed more superior degradation efficiency of tetracycline than the most CdS-based materials as reported, and exhibited about 1.8 folds higher hydrogen evolution efficiency than pristine CdS. A direct Z–scheme charge transfer mechanism was proposed by combining radicals trapping experiments and electron paramagnetic resonance spectra, which accelerated the efficient transport of photo-induced charge carriers. The present work demonstrates that CdS/CeO2 nanomaterial with high photocatalytic performance has a promising application in the environmental treatment and green energy production.

Impact of argon ion implantation on CdS nanorod mesh

Ion implantation is explored as potent approach for tuning the optoelectrical properties of semiconducting thin films via controlled defect engineering. This present study investigates the 180 keV argon (Ar+) ion implantation on the cadmium sulfide (CdS) nanorod mesh; synthesized via chemical bath deposition (CBD) method. X-ray diffraction (XRD) analysis supports the consistency of hexagonal phase even after implantation, but variation in the intensity of diffraction planes is noted. Field emission scanning electron microscopy (FESEM) scans are recorded to examine the implantation effect on the surface morphology. Implantation induces lattice disorder that resulted decrease in band gap energy from 2.39 eV to 2.08 eV and the corresponding green-yellow-red emission bands are discussed in photoluminescence (PL) spectra.

Impact of the number of surface-attached tungsten diselenide layers on cadmium sulfide nanorods on the charge transfer and photocatalytic hydrogen evolution rate

The selection of layered number and time-course destruction of layers may affect the charge transfer between 2D-to-1D heterostructure, making it possible to improve the efficiency of solar-to-hydrogen evolution. Herein, we demonstrate a simple, low-cost systematic protocol of 2D-WSe2 nanolayer numbers ranging from 7 to 60 aiding the ultrasonication time-course. The resultant nanolayers were assembled on the surface of 1D-CdS nanorods, which demonstrated an improved surface shuttling property. Consequently, a drastic improvement in photocatalytic solar-driven hydrogen evolution was observed (103.5 mmol h−1 g−1) with seven-layered WSe2 (few-layered WSe2) attached on CdS nanorods surface. This enhanced photocatalytic performance is attributed to the selection of layers on CdS surface that expose abundant active sites; along with suitable energy levels, this can facilitate increased charge transfer leading to feasible photocatalytic reactions. Significantly, the present study proposes an efficient and sustainable process to produce hydrogen and demonstrates the potential of numbered WSe2 nanosheets as a co-catalyst material.

Preparation and photocatalytic performance of CdS@Bi2WO6 hybrid nanocrystals

The hybrid nanocrystals of cadmium sulfide (CdS) and bismuth tungstate (Bi2WO6) (CdS@Bi2WO6) were well-prepared in the nanoreactors of Bi2WO6-contained sodium polyacrylate (PAANa) latex particles, by means of cadmium sulfate/sodium sulfide (CdSO4/Na2S) solutions absorption and solvothermal treatment. The influences of CdSO4/Na2S millimolar ratio on structure and photocatalytic performance of hybrid nanocrystals were investigated. With 3:1 of Cd2+/S2- millimolar ratio in feeding, CdS nanorods on the surface of Bi2WO6 cluster were obtained and its length increased after solvothermal treating; the resultant CdS@Bi2WO6 degraded 96.1% of RhB after illuminating for 120 min, which was more effective than others. With the 1:2 or 1:3 of Cd2+/S2- millimolar ratio, the solvothermal treated cubic-CdS were agglomerated to cluster which attached on the surface of Bi2WO6 cluster, and the agglomerates size increased accordingly. The photocatalytic mechanism suggests that the superoxide ions and holes were the active species produced by CdS@Bi2WO6 in the photocatalytic process. The grown CdS nanorods on the surface of Bi2WO6 had better charge separation ability than the grown CdS clusters on the surface of Bi2WO6. The CdS@Bi2WO6 hybrid nanocrystal with the definite-designed structure will possess the excellent photocatalytic performance.

Identification of the Charge Transfer Channel in Cobalt Encapsulated Hollow Nitrogen-Doped Carbon Matrix@CdS Heterostructure for Photocatalytic Hydrogen Evolution.

Water splitting to H2 by photocatalysis remains an effective strategy to alleviate the energy crisis. Unfortunately, single-component photocatalyst still suffers from sluggish reaction kinetics. In this work, a noble-metal free photocatalytic system of nitrogen-doped carbon@Co embedded in carbon nanotubes (NC@Co-NCT)/cadmium sulfide (CdS) is fabricated by coupling CdS nanorods with the metal-organic framework-derived Co encapsulated nitrogen-doped carbon (NC) material. The optimal photocatalytic activity of NC@Co-NCT/CdS is determined to be 3.8 mmolh-1 g-1 , which is ≈5.8 times of CdS. By combining the experimental evidences and density functional theory calculations, a novel photoelectron transfer channel in the heterojunction interfaces is revealed, expediting the migration and separation of photo-induced charge carriers of CdS. Moreover, the presence of Co nanoclusters can act as the active sites, boosting the H2 evolution reaction. This study can present a new avenue to design advanced photocatalysts with high-efficiency electrons and holes separation.

Scaling-up photocatalytic activity of CdS from nanorods to nanowires for the MB degradation

The development of a scalable and facile method for the synthesis of visible light driven photocatalytic materials to degrade toxic organic dyes is highly challenging and essential. In this regards, cadmium sulfide (CdS) nanorods and nanowires with controlled aspect ratio, grain size, surface area, and bandgap were synthesized by a simple solvothermal method, and their photocatalytic performances were exploited for the photo-degradation of methylene blue (MB) under simulated solar light. Extensive structural characterizations to identify the origin of the activities were performed. The photocatalytic activity measurements showed that the degradation of MB was 94.41%, 97.24%, 97.88%, and 99.82% for CdS prepared by following four different synthesis routes and increasing trend showed a correlation with the nanostructure morphology changing from nanorod and nanowires with increasing aspect ratio. It has been found that CdS nanowires show more pronounced photocatalytic activity due to the efficient separation of photo-generated electron-hole pairs induced by increased the aspect ratio and higher active surface area.

NiO Nanosheets Coupled With CdS Nanorods as 2D/1D Heterojunction for Improved Photocatalytic Hydrogen Evolution.

Designing low-cost, environment friendly, and highly active photocatalysts for water splitting is a promising path toward relieving energy issues. Herein, one-dimensional (1D) cadmium sulfide (CdS) nanorods are uniformly anchored onto two-dimensional (2D) NiO nanosheets to achieve enhanced photocatalytic hydrogen evolution. The optimized 2D/1D NiO/CdS photocatalyst exhibits a remarkable boosted hydrogen generation rate of 1,300 μmol h−1 g−1 under visible light, which is more than eight times higher than that of CdS nanorods. Moreover, the resultant 5% NiO/CdS composite displays excellent stability over four cycles for photocatalytic hydrogen production. The significantly enhanced photocatalytic activity of the 2D/1D NiO/CdS heterojunction can be attributed to the efficient separation of photogenerated charge carriers driven from the formation of p-n NiO/CdS heterojunction. This study paves a new way to develop 2D p-type NiO nanosheets-decorated n-type semiconductor photocatalysts for photocatalytic applications.

Single-Atom-Based Heterojunction Coupling with Ion-Exchange Reaction for Sensitive Photoelectrochemical Immunoassay.

Benefiting from the maximum atom-utilization efficiency and distinct structural features, single-atom catalysts open a new avenue for the design of more functional catalysts, whereas their bioapplications are still in their infancy. Due to the advantages, platinum single atoms supported by cadmium sulfide nanorods (Pt SAs-CdS) are synthesized to build an ultrasensitive photoelectrochemical (PEC) biosensing platform. With the decoration of Pt SAs, the PEC signal of CdS is significantly boosted. Furthermore, theory calculations indicate the positively charged Pt SAs could change the charge distribution and increase the excited carrier density of CdS. Meanwhile, it also suggests that Cu2+ can severely hinder the photoexcitation and electron-hole separation of CdS. As a proof of concept, prostate-specific antigen is chosen as the target analyte to demonstrate the superiority of the Pt SAs-CdS-based PEC sensing system. As a result, the PEC biosensor based on Pt SAs-CdS exhibits outstanding detection sensitivity and promising applicability.

Gamma-ray induced modifications on CdS nanorod mesh:Structural, optical, and electrical properties

In present research work, gamma ray (γ-ray) induced modifications on the cadmium sulphide (CdS) nanorod mesh are investigated. CdS nanorod mesh is deposited on the glass substrate via chemical bath deposition. The samples are irradiated with Co-60 γ-rays with varying dose up to 200 kGy. Structural, optical, and electrical properties of CdS nanorod mesh are examined after exposure to gamma radiation. XRD pattern of pristine and gamma irradiated CdS nanorods revealed no phase transformation but variation in the relative intensity is visible. Moreover, the crystallite size is found to increase with the gamma dose. In addition, FESEM imaging displayed the morphology of pristine and gamma irradiated CdS nanorods. Furthermore, optical properties are also studied to check the effect of gamma irradiation on the respective parameters. The gamma radiation also produces significant changes in the transport properties of CdS nanorods. With gamma dose, CdS nanorod mesh displayed an increment in the current values due to ionization, defects and grain coalescence.

Synthesis and characterization of novel poly(HAzPMA-co-SA)/RDX/CdS nanocomposite as a polymer bonded explosive

Cadmium sulfide nanorods with a length of 69 nm have been prepared by using Cd(OAc)2.2H2O and S8 at 125 °C in the presence of triethylenetetramine as the template agent and coordination agent and characterized by using X-ray diffraction, transmission electron microscopy, FTIR, photoluminescence, and UV–vis absorption spectroscopic techniques. Photocopolymerization of glycidyl methacrylate (GMA) and sodium acrylate (SA) was carried out using CdS nanorods as a photocatalyst under UV light exposure at 400 nm in the presence of β-cyclodextrin (β-CD). To optimization of the effective parameters on the synthesis of copolymer nanocomposite, the amounts of initiator, monomers, and β-CD, duration of pre-deoxygenation, and light wavelength were evaluated. Ring opening of poly(GMA-co-SA)/CdS nanocomposite with NaN3 afforded poly(HAzPMA-co-SA)/CdS nanocomposite and subsequent mixing with RDX in DMF led to the formation of poly(HAzPMA-co-SA)/RDX/CdS nanocomposite as a polymer bonded explosive. All of the copolymer nanocomposites were characterized using various tools of instrumental analysis.

Approach of fermi level and electron-trap level in cadmium sulfide nanorods via molybdenum doping with enhanced carrier separation for boosted photocatalytic hydrogen production

Doping semiconductor with non-noble metal is a promising strategy to modulate the electronic structures and therefore develop efficient photocatalysts. In this study, we report a facile one-pot solvothermal strategy to synthesize Mo-doped CdS nanorods (NRs) using ammonium tetrathiomolybdate as the sources for both of S and Mo, cadmium acetate as the Cd source, and ethanediamine as the solvent heated at 180 °C for 24 h. The experimental characterizations and theoretical calculations reveal that Mo in the form of Mo4+ is incorporated into the CdS lattice to substitute Cd2+ ions and the Mo-S-Cd bonds are formed accordingly. The Mo doping not only introduces localized electron-trapping states at the bottom of conduction band minimum, but also elevates the Fermi level towards the defect level, which endows the doped system with enhanced n-type characteristic and the defect state with strong electron-trapping ability. Moreover, a nonuniform distribution of charge density is formed for the Mo-doped CdS NRs, facilitating the separation of photoexcited charge carriers. Therefore, the Mo-doped CdS NRs exhibit remarkably enhanced photocatalytic activity, with an average H2 production rate of 14.62 mmol·g−1·h−1 without using Pt as the co-catalyst, about 5.8 times higher than that of bare CdS. This work provides new insight into the facile synthesis of visible-light-driven photocatalysts as well as the effect of metal ion doping on the modulation of electronic structures.

Cover Feature: Indium Phosphide Quantum Dots Integrated with Cadmium Sulfide Nanorods for Photocatalytic Carbon Dioxide Reduction (ChemCatChem 18/2020)

Cover Feature: Indium Phosphide Quantum Dots Integrated with Cadmium Sulfide Nanorods for Photocatalytic Carbon Dioxide Reduction (ChemCatChem 18/2020)

Indium Phosphide Quantum Dots Integrated with Cadmium Sulfide Nanorods for Photocatalytic Carbon Dioxide Reduction

AbstractPhotocatalytic conversion of CO2 into storable fuels is an attractive way to simultaneously address worldwide energy demands and environmental problems. Semiconductor quantum dots (QDs) have gained prominence as candidates for photocatalytic applications due to their many advantages, which include tunability for advanced electronic, optical, and surface properties. Indium phosphide (InP) quantum dots are semiconducting QDs with enormous potential for solar‐driven CO2 reduction. Their advantages include a tunable bandgap, diverse surface chemistry, and nontoxicity. InP QDs and CdS nanorods were integrated using a simple and inexpensive method. CO2 photoreduction by the CdS‐InP composites was evaluated in aqueous solution using triethanolamine as a sacrificial donor. The crystal structures, surface compositions, and morphologies were investigated via X‐ray diffraction analysis, X‐ray photoelectron spectroscopy, and transmission electron microscopy, respectively. The UV‐visible diffuse reflectance spectra of the CdS‐InP composites indicated efficient visible light utilization in the 500–550 nm range. The results of photoelectrochemical and photoluminescence analyses illustrated effective charge separation in the composites. The photocatalytic activity of the as‐synthesized composites was superior to that of pure CdS. The CO evolution rate of the optimized composite was 216 μmol h−1 g−1 during the first three hours of irradiation and increased steadily over the next 62 hours. We also studied the influences of different solvents, the hole scavenger concentration, and catalyst loading on the performance of the optimized composite.

Fabrication of CdS Nanorods on Si Pyramid Surface for Photosensitive Application.

It is the first time that cadmium sulfide (CdS) nanorods have been fabricated on silicon (Si) pyramid surface by the hydrothermal reaction method. In our work, the Si pyramid morphology is able to increase the adhesion between the CdS seed layer and Si wafer. Hence, it is critical for CdS nanorods to grow successfully. During the fabrication process, the glutathione is used as the complexing agent for the formation of the CdS nanorods. By continuously adjusting the experimental conditions, the thickness of the CdS seed layer, the concentration of the glutathione, and the temperature and time of the hydrothermal reaction, the optimal condition for CdS nanorods growth on Si pyramid surface is 80 nm seed layer, 0.2–0.3 mmol glutathione, 200 °C, and 1.5 h. The Cd and S elements have a ratio of 1:1.03 from the energy-dispersive spectroscopy test, which is in agreement with the stoichiometric composition of CdS. The CdS nanorods have a bandwidth of 2.22 eV through the optical absorption spectra. The photosensitivity response test results reveal these CdS nanorods on the Si pyramid structure have an obvious photosensitive effect. From the analysis, the CdS nanorods can grow on any morphological Si surface if the adhesion between the CdS seed layer and the Si surface is strong enough.

Pyroelectric effect in CdS nanorods decorated with a molecular Co-catalyst for hydrogen evolution

Abstract Hexagonal cadmium sulfide (CdS) with a noncentro-symmetric structure exhibits piezoelectric and pyroelectric effect due to spontaneous polarization changes companied by temperature variation. However, its pyroelectric effect in pyroelectro-catalytic hydrogen evolution has not been well identified. Herein, we found that CdS nanorods decorated with an organic molecule 2-mercaptobenzimidazole (2MBI) can greatly enhance the pyroelectro-catalytic hydrogen evolution activity. The 2MBI acted as a molecular co-catalyst improves the pyroelectric property of CdS and enhances the separation of pyroelectro-induced charges. Under thermal cycling between 25 °C and 55 °C, CdS-2MBI shows apparently improved pyroelectro-catalytic H2 evolution activity, which is about 5 folds of that for CdS alone. This work may initiate a new prospect for pyroelectric effect in photocatalysis, such as the photocatalytic hydrogen evolution under natural temperature fluctuations.

Controlled Growth and Bandstructure Properties of One Dimensional Cadmium Sulfide Nanorods for Visible Photocatalytic Hydrogen Evolution Reaction.

One dimensional (1D) metal sulfide nanostructures are one of the most promising materials for photocatalytic water splitting reactions to produce hydrogen (H2). However, tuning the nanostructural, optical, electrical and chemical properties of metal sulfides is a challenging task for the fabrication of highly efficient photocatalysts. Herein, 1D CdS nanorods (NRs) were synthesized by a facile and low-cost solvothermal method, in which reaction time played a significant role for increasing the length of CdS NRs from 100 nm to several micrometers. It is confirmed that as the length of CdS NR increases, the visible photocatalytic H2 evolution activity also increases and the CdS NR sample obtained at 18 hr. reaction time exhibited the highest H2 evolution activity of 206.07 μmol.g−1.h−1. The higher H2 evolution activity is explained by the improved optical absorption properties, enhanced electronic bandstructure and decreased electron-hole recombination rate.

Highly exposed (001) facets Ni(OH)2 induced formation of nickle phosphide over cadmium sulfide nanorods for efficient photocatalytic hydrogen evolution

An efficient Ni2P–CdS photocatalyst for photocatalytic hydrogen evolution was synthesized by phosphorizing β-Ni(OH)2 nanosheet with exposed (001) facets on CdS nanorods. The obtained Ni2P–CdS composite displays an outstanding and stable photocatalytic hydrogen generation rate of 68.47 mmol g−1 h−1 in 10 vol% lactic acid under visible light irradiation, more than 17 times higher than that for pure CdS nanorods. The transient photocurrent response, EIS measurement, Mott-Schottky plots, acidic LSV measurement, and PL spectra have proved that Ni2P loading can significantly improve the separation of photo-excited electron-hole pairs in CdS nanorods and enhance the hydrogen evolution capability for CdS. These improvements are achieved by features of Ni2P such as the high capability of trapping photo-generated electrons from CdS, lifting the total Fermi level and lowering the hydrogen evolution overpotential of the composite. The results show that β-Ni(OH)2 precursor with a high exposure degree of (001) facet is contributed to the epitaxial formation of (001)-facet-exposed Ni2P co-catalyst on CdS nanorods, resulting in that the Fermi level and the hydrogen evolution overpotential of the composite can be further lifted and lowered. This study has provided a novel precursor-derived route to fabricate high-performance co-catalysts with highly exposed active facets on CdS nanorods for effective photocatalytic hydrogen evolution.

Self-assembly of zinc cadmium sulfide nanorods into nanoflowers with enhanced photocatalytic hydrogen production activity

ZnCdS solid solutions have been extensively studied due to their excellent photocatalytic hydrogen evolution performance. The change of the molar ratio of precursors affects the morphology and structure of ZnCdS, with the subsequent influence on the separation of photogenerated electron–hole pairs and the hydrogen production ability. The effect of the amount of nonmetallic elements on the photocatalytic activity has been scarcely explored. In this work, the morphology of ZnCdS is regulated by varying the amount of thioacetamide as S precursor. The structure of the samples is thoroughly analyzed by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis. Their optical properties, photocatalytic hydrogen evolution ability, and photoelectrochemical performance are evaluated. Upon increasing the amount of thioacetamide, the crystallinity improves, the ZnCdS nanorods self-assemble into nanoflowers, and the number of defects decreases. The highest photocatalytic activity is achieved for a (Zn + Cd):S molar ratio of 1:3.5. Moreover, the photocatalyst exhibits excellent stability after six cycles. The one-dimensional nanorod structure contributes to the formation of a space charge region that drives the charge carriers along the nanorods. The self-assembled ZnCdS nanoflowers provide extra channels for the charge transfer, improving the separation of electron–hole pairs.

Performance improvement of organic resistive memories by exploiting synergistic layered nanohybrid dispersed polymer composites

Functionalized layered nanohybrid materials have been thoroughly explored in numerous practical applications including photocatalysis, supercapacitors, and sensors, and have inherent potential to excel in the field of organic resistive random access memory devices as well. Herein, we report an efficient, facile, and cost-effective in situ synthesis route to prepare a layered nanohybrid by grafting cadmium sulfide (CdS) nanorods with exfoliated graphene oxide (GOs) sheets via the one-step hydrothermal functionalization technique. Such a nanohybrid material displays advantageous characteristics possessed by them due to the formation of organic–inorganic heterojunctions at their interface. Sandwiched devices, with a configuration of ITO/reduced graphene oxide–CdS/poly-methyl methacrylate (PMMA)/Al, are fabricated by dispersing different wt. % of the layered nanohybrid in a poly-methyl methacrylate (PMMA) matrix. Detailed current density vs voltage (J–V) studies exhibit excellent bipolar resistive switching characteristics reaching a very low set voltage of ∼−0.48V, high current ION/IOFF ratios of ∼106, and ultralow set/reset power densities of ∼10−8/10−6W/cm2 for devices containing 0.4 wt. % nanohybrid nanofillers. Partial reduction of GOs and the formation of heterojunctions during the synthesis process undoubtedly boost the resistive memory performances resulting from the synergistic effect in layered nanohybrid materials. The fabricated devices have been subjected to various analyses in order to test their stability, repeatability, and reliability, all of which have been found to display encouraging results.

Effect of temperature on properties of cadmium sulfide nanostructures synthesized by solvothermal method

Large surface area to volume ratio of the nanostructured materials is familiar to play an important role in novel catalytic, sensing and optoelectronics application. In current research work, CdS nanostructures are synthesized by solvothermal process. This synthesis is carried out at different temperatures of 140 °C, 160 °C, 180 °C and 200 °C. The structural, morphological, optical, elemental and electrical properties of cadmium sulfide nanostructures are investigated using X-Ray Diffractometry (XRD), Field Emission Scanning Electron Microscope (FESEM), UV–Visible spectroscopy, photoluminescence spectrometry (PL), FTIR and two probe set up assisted with Keithley source meter. XRD pattern confirmed the formation of hexagonal wurtzite structure for all the solvothermal temperatures. FESEM analysis depicted the formation of cadmium sulfide nanorods in any possible orientation with high density. EDS is also performed to confirm the elemental composition of CdS nanostructures. The UV–Vis spectroscopy revealed that optical band gap increased at low solvothermal temperature indicating the confinement effects in CdS nanostructures. These cadmium sulfide nanostructures may have the potential application in hydrogen production, optoelectronics devices and gas sensing.