Introduction Of CdS Research Articles

Porous g-C3N4 tubes in-situ anchored by waste biomass-derived carbon dots for photocatalytic reduction of sunset yellow and Escherichia coli in juice

Chemical hazardous substances and hazardous pathogenic bacteria pose a serious risk to human health. The development of efficient, safe and simple removal technologies is urgent. In this study, waste biomass derived carbon dots in-situ anchored porous g-C3N4 tubes were prepared by supramolecular self-assembly method. The prepared photocatalyst exhibited enhanced light absorption, large surface area, and abundant reactive sites. Photoelectrochemical analyses confirmed that the introduction of CDs could effectively promote the separation and transfer of photogenerated carriers with enhanced degradation of sunset yellow (95.4 %) and inactivation of Escherichia coli (98.3 %) under visible light. Furthermore, the development of g-C3N4 loaded floatable porous alginate sponges for the simultaneous removal of E. coli and sunset yellow from fruit juices, obtaining efficient purification results and satisfactory overall acceptability. This work provides a feasible pathway for photocatalytic decontamination of contaminated liquid food.

Unveiling ternary NiS@NC/CdS heterojunction synergistically induced superior photo/electrocatalytic hydrogen evolution

Herein, a ternary NiS@NC/CdS heterojunction is designed and synthesized by in situ depositing CdS on the hierarchical flower-like NiS2@NC derived from porous Ni-ZIF template for a superior photo/electrocatalytic hydrogen evolution. The findings reveal that the introduced Cd atoms could react with S atoms from NiS2 to form CdS, and meantime the original NiS2 crystal phase transforms into a new NiS phase, which results in tight contact between CdS and NiS, and further facilitates efficient formation of ternary heterojunction among CdS, NiS and N doped porous carbon. As a result, the synthesized ternary NiS@NC/CdS heterojunction exhibits a superior photocatalytic hydrogen generation activity, up to 15.4 mmol/gcat in 3 hours, in the absence of Pt cocatalyst, which is 2.3 and 230 times higher than that of NiS2@NC and CdS, respectively. The results demonstrate that the introduction of CdS can efficiently enhance the production of photogenerated carriers, and the presence of ternary heterojunction can further improve the separation and transportation efficiency of photogenerated carriers. Moreover, density functional theory (DFT) calculations demonstrate that the presence of CdS and carbon efficiently reduces the adsorption energy of H*, leading to a significant enhancement of hydrogen evolution performance. This work provides a new perspective for improving the photo/electrocatalytic activity of MOFs-derived carbon materials.

Efficient photocatalytic production of H2O2 and photodegradation of tetracycline by CdS/square tubular g-C3N4 S-scheme heterojunction photocatalyst

Photocatalytic technology is an effective method for clean energy production and wastewater treatment. In this work, a square tubular g-C3N4 (MCN) is first synthesized by the aid of thermal polymerization of melamine in mixed KCl/LiCl molten salt and then loaded with CdS nanoparticles via a solvothermal method to obtain the final composite (MCN@CdS). This complex exhibits dual catalytic characteristics: photocatalytic oxygen reduction to produce hydrogen peroxide and photocatalytic degradation ability of antibiotics. The specific surface area (SSA) of MCN was enhanced by calcination with the help of molten salt, and the introduction of CdS expanded the absorption edge of MCN@CdS. In addition, electrochemical impedance and photocurrent spectroscopy confirmed that separation and migratory efficiency of photoproduced charge carriers could be promoted by the combination of MCN and CdS. As a result, the yield of hydrogen peroxide photocatalyzed by MCN@CdS is up to 0.95 mmol· L−1 in 80 min under visible light, which is 1.2 and 1.9 times larger than that of pure MCN and CdS. More importantly, the removal rate of tetracycline photocatalyzed by MCN@CdS, within 30 min with the participation of O2, achieved up to 99.5 %, 4 times faster than that in O2-free environment.

Construction of ZnO@CDs@Co3O4 sandwich heterostructure with multi-interfacial electron-transfer toward enhanced photocatalytic CO2 reduction

Photocatalytic conversion of CO2 into small-molecule chemical feedstocks can meet the growing demand for energy and alleviate the global warming. Herein, a p-n ZnO@CDs@Co3O4 heterojunction with sandwich structure was constructed by calcination method of self-assembled ZIF-8@CDs@ZIF-67. The ZnO@CDs@Co3O4 with well-defined interfacial structure exhibited the significantly enhanced photocatalytic CO2 reduction activity, and the optimal catalyst indicated the (CO + CH4) evolution rate of 214.53 µmol g−1 h−1 under simulated solar light, which was superior to ZnO, Co3O4 and binary ZnO@Co3O4. The internal cavity, exposed active sites, multiple interfaces and constructed p-n heterojunction can facilitate the light harvesting and photoexcited electron transfer. Besides, after introduction of CDs placed in the middle layer between ZnO and Co3O4, CDs with excellent photoelectric property further promoted charge separation and migration. This work represents an appealing strategy to construct well-defined photocatalysts for boosting CO2 photoreduction.

Enhanced pyro-/photo catalysis of the pyroelectric PZT/CdS heterostructure for dye decomposition driven by visible light and cold-hot cycles

Semiconductor heterojunction have received wide attention for their enhanced catalytic properties. In this paper, the PZT/CdS pyroelectric heterojunction prepared by hydrothermal method has remarkable pyro-/photo catalytic degradation performance and RhB can be almost completely degraded within 120 min. The pyro-/photo catalytic degradation of RhB by PZT/CdS was 99.25% under 20–55 °C and visible light irradiation, which was 1.5 times and 6 times that of PZT/CdS (64.72%) and PZT (16.35%) photocatalysis, respectively. The increase of decomposition rate is because the introduction of CdS not only expands the light response range of the material, but also improves the redox ability of the material. At the same time, CdS and PZT can also produce pyroelectric effect under temperature fluctuation. Double pyroelectric effect and heterojunction work together to further promote the separation of carriers. This study confirmed that PZT/CdS heterojunctions based on pyroelectric effect can achieve efficient pyro-/photo catalysis by using solar/thermal energy, which provides a reference in the field of catalytic degradation of dye wastewater by multiple energy sources.

Construction of 3D carbon dots/Prussian blue analogue-derived phosphide nanocomposites on Ni foam for high-performance supercapacitors

A desirable electrode material with rational architecture and superior composition is the key to optimize the electrochemical performance of supercapacitor. Prussian blue analogues are a kind of promising precursors for electrode preparation with the features of adjustable compositions and rigid frame structure. In this work, carbon dots/nickel iron phosphide nanoparticles grown on Ni foam have been delicately designed and synthesized from PBAs for the application of cathode of hybrid supercapacitors (HSC). Introduction of CDs is found that not only favors the nanocubes growth of PBAs precursor but also alleviates aggregation of the nanocubes during calcination and phosphorization. The uniform coverage of carbon dots on the phosphides offers hydrophilic interfaces beneficial to the interaction between electrodes and electrolyte and improves the chemical stability of the electrodes. With these assets, the optimum electrode exhibits remarkable areal capacitance (2589 mF cm−2 at a current density of 2 mA cm−2), noteworthy rate performance and excellent cycling stability. Moreover, the as-fabricated hybrid supercapacitor shows a high energy density and power density, as well as high stability. These results indicate that the CDs/NiFeP-NF electrode has the desirable potential to be a candidate for energy storage devices. The structure modulation in this work may provide a new avenue for development of PBAs-based phosphides materials in the field of energy conversion and storage.

Effect of Cation Exchange Time on the Morphology and Photoactivity of CdS/Ag2S Composites for Ciprofloxacin Degradation

Herein, the effect of reaction time in the cationic exchange method on the CdS/Ag2S structure and photocatalytic activity is investigated. A hydrothermal approach is used to produce CdS nanorods, and then a cation exchange method is applied to synthesize CdS/Ag2S composites. The heterostructure between CdS and Ag2S is determined by the X‐ray diffraction and transmission electron microscopy studies. Comparing pure CdS NRs and CdS/Ag2S by the UV–vis diffuse reflection spectra data, the introduction of Ag2S is proven to enhance the light absorption in visible region. The Brunauer–Emmett–Teller method indicates that CdS and CdS/Ag2S are mesopore materials and the specific surface areas of CdS, CdS/Ag2S‐15, CdS/Ag2S‐30, and CdS/Ag2S‐60 samples without and with a cation‐exchange reaction time of 15, 30, and 60 min are 305, 900, 187, and 52 m2 g−1, respectively. The photocatalytic activity of CdS/Ag2S is examined through the ciprofloxacin photodegradation. The ciprofloxacin degradation rate increases with the introduction of CdS and reached a maximum value of 60% within 180 min for CdS/Ag2S‐15 under simulated sunlight irradiation, which is 1.5 times greater than that of pure CdS. The ciprofloxacin degradation rate decreases as the cation‐exchange reaction time is increased to 60 min (26% after 180 min illumination).

Carbon dots and carbon nitride composite for photocatalytic removal of uranium under air atmosphere

Photocatalytic removal of uranium has attracted much attention in nuclear wastewater treatment and it is highly needed to develop functional photocatalyst with excellent removal performance. In this work, seven kinds of carbon dots/carbon nitride (CDs/CN) composites were synthesized and SerCDs/CN with the best photo-assisted uranium removal performance was screened out. It was found that the introduction of CDs could bring in higher photocurrent density, lower interfacial charge transfer impedance and narrower band gap, resulting in a much-improved removal performance. SerCDs/CN had shown a removal capacity as high as 1690 mg/g and the reaction could be operated under air atmosphere which is promising in real application.

Preparation of CdS/Cs0.68Ti1.83O4 heterojunction for promoted photocatalytic hydrogen evolution reaction

Perovskites have attracted significant interest in the field of photocatalysis due to their excellent stability, rich crystal chemistry, and high catalytic activities. However, they usually require the presence of noble metal cocatalysts as their band gaps are typically greater than 3.0 eV. In this study, a layered titanate with lepidocrocite (γ-FeOOH)-type structure (Cs0.68Ti1.83O4) was synthesized via solid state reaction, followed by the introduction of CdS through an impregnation method, to produce a composite heterostructure. The CdS/Cs0.68Ti1.83O4 composite displayed superior photocatalytic hydrogen evolution performances without noble metal cocatalyst. Possessing an extended visible light response and facilitating charge carrier migration, the CdS-50%-Cs0.68Ti1.83O4 composite exhibited photocatalytic H2 evolution rate of 120.0 μmol/h and quantum efficiency of 3.41% under 400 nm light irradiation. Furthermore, a double-charge transfer mechanism was proposed for the CdS/Cs0.68Ti1.83O4 composite based on the results from UV–vis/DRS, XPS, and Mott-Schottky characterizations.

Preparation of a g-C3N4/UiO-66-NH2/CdS Photocatalyst with Enhanced Visible Light Photocatalytic Activity for Tetracycline Degradation

A combination of calcination and hydrothermal processing was used to prepare a g-C3N4/UiO-66-NH2/CdS photocatalyst, and the degradation of tetracycline (TC) over this material was assessed. The photocatalytic performance of this nanocomposite was approximately 4.4 and 2.3 times those of CdS and g-C3N4, respectively, and was found to be affected by the CdS loading amount, the pH of the reaction solution and the initial TC concentration. This catalyst also exhibited stable performance over four consecutive reaction cycles. The highly enhanced photoactivity of the g-C3N4/UiO-66-NH2/CdS is attributed to the introduction of CdS, which widens the range over which the material absorbs visible light and inhibits the recombination of electron–hole pairs. The results of this study suggest further applications for this material in the treatment of contaminated wastewater powered by solar energy.

Formation of mesoporous Co/CoS/Metal-N-C@S, N-codoped hairy carbon polyhedrons as an efficient trifunctional electrocatalyst for Zn-air batteries and water splitting

It remains a huge challenge to design and realize trifunctional high-efficiency and low-cost electrocatalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, with the introduction of CdS and ferrocene, a metal–organic framework (MOF)-induced strategy is reported to synthesize a hierarchical trifunctional electrocatalyst based on Co/CoS nanoparticles and metal (Co, Fe)-N-C species in a hairy S, N-codoped mesoporous carbon polyhedron interwoven with carbon nanotubes (Co/CoS/Fe-HSNC). The specific roles of Co, CoS and (Co, Fe)-N-C active species in Co/CoS/Fe-HSNC catalyst for ORR, OER and HER are also well recognized. Besides, CdS nanoparticles is demonstrated to act as a pore former and S sources both for reaction and doping, and ferrocene is employed to initiate the in-situ growth of carbon nanotubes and Fe-N-C active sites which both contribute to superior multifunctional activities. Benefitting from the rationally designed nanostructures, the ORR half-potential of the Co/CoS/Fe-HSNC electrocatalyst reaches 0.906 V in 0.1 M KOH, about 65 mV larger than commercial Pt/C electrocatalyst, and a low overpotential of 250 mV is achieved for OER and 138 mV for HER at a current density of 10 mA cm−2. Constructed with the Co/CoS/Fe-HSNC catalyst, a Zn-air battery exhibits a high power density of 213 mW cm−2 and a small charge/discharge voltage gap of 0.79 V at 2.0 mA cm−2. The presented strategy provides new insight into the construction of MOF-derived hierarchical multifunctional catalysts for Zn-air batteries and water electrolysis.

Construction of photocathodic bioanalytical platform based on Z-scheme polyimide/CdS composite assisted by dual-catalysis system

Herein a signal-on photoelectrochemical enzyme biosensor is successfully designed for sensitive monitoring of hypoxanthine based on the Z-scheme composite of polyimide/CdS. Xanthine oxidase (XOD) is integrated into the polyimide/CdS composite to construct an enzyme sensor. Due to its unique properties, polyimide (PI) not only has the ability of semiconductor to separate and transfer photogenerated electron-hole pairs, but also acts as a peroxide mimic enzyme to catalyze the reduction of H2O2, while the introduction of CdS is conducive to the light absorption of PI, and can also transfer the photogenerated electrons and holes generated by PI in time to obtain a more stable and larger photocurrent signal. Unlike the common O2-dependent suppression of the signal, it is found that the cathode photocurrent becomes larger with the increase of the substrate concentration in a certain range. This interesting phenomenon is ascribed to the dual-catalysis system formed by the synergistic action of XOD and polyimide, and the use of cathode photocurrent also avoids the interference from reducing substances in the system. The constructed enzyme biosensor has a wide detection range from 10.0 μM to 10.0 mM and exhibits favorable analytical performance including good selectivity, sensitivity and high stability.

CdS@3DOM TiO2–ZrO2 composites with high efficiency photocatalytic properties prepared by template method combined with in-situ self-assembly technology

The three-dimensional ordered macroporous composites CdS@3DOM TiO2–ZrO2 were prepared by the template method combined with in-situ self-assembly technique. The composition, structure, morphology and surface physicochemical properties of composites were characterized by XRD, XPS, UV–vis/DRS, SEM, TEM, HR-TEM, PL, N2 adsorption−desorption and EIS tests. The results show that CdS@3DOM TiO2–ZrO2 composites have strong light absorption in the visible region. And the in-situ self-assembled CdS particles in the composite do not destroy the excellent open pore structure, and the introduction of CdS further improves the charge separation efficiency. The results of multi-mode photocatalytic degradation of CdS@3DOM TiO2–ZrO2 show that the photocatalytic properties of CdS@3DOM TiO2–ZrO2 composites are obviously enhanced. In addition, the hydrogen production of CdS@3DOM TiO2–ZrO2 can reach 1323 μmol/g (8 h) in the photolysis of water experiment, which is 94.5 times than that of the commercially available P25, showing excellent photocatalytic performance.

Photoelectrochemical performances of Fe2O3 nanotube films decorated with cadmium sulfide nanoparticles via photo deposition method

Hematite is an appropriate compound for photoelectrochemical water splitting. However, passive surface state, high recombination rate of the photo induced electron-hole pairs and poor and slow charge transfer kinetics restrict the performance of hematite. In this work, CdS/Fe2O3NTs samples have been successfully prepared by coating of CdS nanoparticles on the surface of the self-organized Fe2O3NTs via photo deposition technique in order to enhance charge separation and charge transfer kinetics. FESEM (Field Emission Scanning Electron Microscopy), XRD (X-ray diffraction), DRS (Diffraction Reflection Spectroscopy) and XPS (X-ray Photoelectron Spectroscopy) analyses have been used to characterize the CdS/Fe2O3NTs photoelectrodes obtained. CdS/Fe2O3NTs has an intense visible light absorption and displays a red-shift of the band edge in comparison with the bare Fe2O3NTs, according to DRS test. The photocurrent density of Fe2O3NTs increased approximately 5 times upon coating with CdS, as shown by photoelectrochemical measurements, indicating the significant role of the introduction of CdS in the enhancement of photo catalytic activity. CdS/Fe2O3NTs may be promising and effective photoanodes in PEC water splitting given their simple preparation and good performance.

Facile Synthesis of Bi2MoO6 Microspheres Decorated by CdS Nanoparticles with Efficient Photocatalytic Removal of Levfloxacin Antibiotic

Developing high-efficiency and stable visible-light-driven (VLD) photocatalysts for removal of toxic antibiotics is still a huge challenge at present. Herein, a novel CdS/Bi2MoO6 heterojunction with CdS nanoparticles decorated Bi2MoO6 microspheres has been obtained by a simple solvothermal-precipitation-calcination method. 1.0CdS/Bi2MoO6 has stronger light absorption ability and highest photocatalytic activity with levofloxacin (LEV) degradation efficiency improving 6.2 or 12.6 times compared to pristine CdS or Bi2MoO6. CdS/Bi2MoO6 is very stable during cycling tests, and no appreciable activity decline and microstructural changes are observed. Results signify that the introduction of CdS could enhance the light absorption ability and dramatically boost the separation of charge carriers, leading to the excellent photocatalytic performance of the heterojunction. This work demonstrates that flower-like CdS/ Bi2MoO6 is an excellent photocatalyst for the efficient removal of the LEV antibiotic.

Fabrication of TiO2 mesoporous microspheres sensitized with CdS nanoparticles and application in photodegradation of organic dye

TiO2 mesoporous microspheres were prepared by water heating reflux of TiO2 precursors obtained via hydrolysis of tetrabutyl titanate. TiO2 microspheres were printed on FTO glass substrate and sensitized with CdS nanoparticles for forming CdS/TiO2 thin film via a successive ionic layer adsorption and reaction process. TiO2 microspheres and CdS/TiO2 thin film were characterized using field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, N2 adsorption desorption measurements, X-ray photoelectron spectroscopy, and UV–Vis absorption spectra. The results indicated that water heating reflux contribute to the crystallization of TiO2 from the amorphous to anatase phase. TiO2 mesoporous microspheres with higher surface area of 268.53 m2/g were formed during the water heating reflux process. A photoresponsive test suggested that the introduction of CdS improves light utilization of TiO2 mesoporous microspheres and reduces recombination of photogenerated electron–hole pairs. Photocurrent density of TiO2 microspheres sensitized with CdS nanoparticles reached 0.2 mA/cm2 while pure TiO2 only obtained 0.036 mA/cm2. The photodegradation performance of the CdS/TiO2 thin film was further investigated. Photodegradation efficiency of CdS/TiO2 thin film reach about 95% within 120 min due to the synergistic effect of CdS and TiO2 heterostructure. The possible catalytic mechanism was also proposed.

Controlled synthesis of 3D flower-like MgWO4:Eu3+ hierarchical structures and fluorescence enhancement through introduction of carbon dots

3D flower-like MgWO4:Eu3+ structures composed of many nanosheets were synthesized and their luminescence can be enhanced through introduction of CDs.

Carbon dots-TiO2 nanosheets composites for photoreduction of Cr(VI) under sunlight illumination: Favorable role of carbon dots

Carbon dots-TiO2 nanosheets (CDs-TNs) composites were synthesized by hydrothermal method and applied for the first time in photoreduction of Cr(VI) under sunlight illumination. The materials were characterized by transmission electron microscope, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectrometer, and X-ray photoelectron spectroscopy analysis. The results confirmed that CDs are successfully incorporated with TNs through TiOC bonds. With the introduction of CDs, CDs-TNs composites exhibit excellent photoreduction performance of Cr(VI), which is higher than that of TNs, P25 and CDs-P25. The unique upconversion property and electron transfer property of CDs play essential roles on light harvesting and charge carriers transferring in the photoreduction process. Most importantly, CDs could facilitate the formation of H2O2, leading to the consumption of holes. As a result, the recombination of photoinduced electron-hole pairs is hindered and photoreduction activity of CDs-TNs is promoted.

CdS nanoparticles decorated anatase TiO2 nanofibers with enhanced visible light photocatalytic activity for dye degradation

A highly dispersed and versatile anatase CdS nanocrystal on TiO2 nanofiber was synthesized by a simple method. The structural and optical properties of the as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–vis absorption spectroscopy. The results show that the CdS nanocrystals with approximately 20–30 nm size are well distributed on the TiO2 nanofibers, and the introduction of CdS increases the light absorption intensity in visible light region. Noticeably, the CdS/TiO2 nanocomposites exhibits excellent photocatalytic activity and reusability, and can be applied to the degradation of various organic dyes, such as methyl orange (MO) and rhodamine-B (RhB). This unique CdS/TiO2 nanocomposites photocatalyst proved to have great potentials for organic contaminants degradation in wastewater.

Fabrication of ferric oxide/reduced graphene oxide/cadmium sulfide heterostructure photoelectrode for enhanced photoelectrochemical performance

A novel high‐efficiency photoelectrode (Fe2O3/reduced graphene oxide/CdS) built from heterostructure and conductive scaffold has been successfully designed and synthesized. Reduced graphene oxide works as a “bridge” which benefits for electron and hole transport. The obtained heterostructure photoelectrodes were systematically characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy, and X‐ray photoelectron spectroscopy (XPS). The photoconversion efficiency (η) and photocurrent densities vs. time (I‐t) curves responding to monochromatic lights have been further investigated in‐depth, which reveals that introduction of CdS and reduced graphene oxide played an important role in the enhancement of photoelectrochemical performance.