Two-step Hydrothermal Synthesis Method Research Articles

Enhancing Photocatalytic Activities for Sustainable Hydrogen Evolution on Structurally Matched CuInS2/ZnIn2S4 Heterojunctions

Effective charge separation and migration pose a critical challenge in the field of solar-driven hydrogen production. In this work, a Z-scheme structured CuInS2/ZnIn2S4 heterojunction was successfully fabricated through a two-step hydrothermal synthesis method to significantly enhance the efficiency of solar-to-hydrogen energy conversion. Structural characterization revealed that the lattice-matched CuInS2/ZnIn2S4 heterojunction exhibits an enlarged interfacial contact area, which facilitates the transfer and separation of photogenerated charges. Microscopic analysis indicated that the CuInS2/ZnIn2S4 composite material has a tightly interwoven interface and a morphology resembling small sugar cubes. Photoelectrochemical spectroscopy analysis demonstrated that the heterojunction structure effectively enhances visible light absorption and charge separation efficiency, leading to an improvement in photocatalytic activity. Hydrogen production experimental data indicated that the CuInS2/ZnIn2S4 heterojunction photocatalyst prepared with a CuInS2 content of 20 wt% exhibits the highest hydrogen evolution rate, reaching 284.9 μmol·g−1·h−1. Moreover, this photocatalyst maintains robust photocatalytic stability even after three consecutive usage cycles. This study demonstrated that the Z-scheme CuInS2/ZnIn2S4 heterojunction photocatalyst exhibits enhanced hydrogen evolution efficiency, offering an effective structural design for harnessing solar energy to obtain hydrogen fuel. Therefore, this heterojunction photocatalyst is a promising candidate for practical applications in solar hydrogen production.

Catalytic combustion of 1,2-dichloroethane via C[sbnd]C/C[sbnd]Cl bond cleavage through core-shell structured CeO2@TiO2 catalyst with excellent catalytic performances

A highly representative chlorinated volatile organic compound (Cl-VOCs), including 1,2-dichloroethane (1,2-DCE), which is extremely hazardous to human health and the environment. Improving the catalytic activity is very important for catalytic degradation of 1,2-DCE. In the work, CeO2@TiO2 catalyst which has a core-shell structure were made by a simple two-step hydrothermal synthesis method for 1,2-DCE oxidation. CeO2@TiO2 catalysts show higher activity (T90=275 °C), better carbon dioxide yield (YCO2=89.54 %) and lower by-products production than primitive CeO2 and TiO2. Due to its core-shell structure, CeO2@TiO2 shows the appropriate oxidation and reduction ability and appropriate acidity distribution, the powerful relationship between Ce and Ti elements in CeO2@TiO2 leads to effectively generate activity Ce3+and oxygen, which is greatly great enhance the activity of CeO2@TiO2 in 1,2-DCE catalytic oxidation. Based on the analysis of 1,2-DCE degradation performance and physical and chemical attributes, it proposes a way to catalyze 1,2-DCE catalytic oxidation over CeO2@TiO2. In addition, CeO2@TiO2 has good stability, and adding water vapor over the CeO2@TiO2 during 1,2-DCE degradation to promote 1,2-DCE conversion. The findings of this study might offer some new suggestions for creating catalysts that will destroy Cl-VOCs in their preparation and design.

Modulating electronic structure of nickel diselenide by vanadium doping toward highly efficient and stable bifunctional electrocatalysts for overall water splitting

Designing low-cost and high-efficiency bifunctional electrocatalysts is one of the challenges in the clean production of hydrogen energy in electrochemical water splitting. Transition metal selenides (TMSes) have been widely studied because of their low price, intrinsic metal properties, and high catalytic activity. In addition, the synergistic effect between bimetallic selenides exhibits better performance than monometallic selenides in the electrocatalytic process. Herein, we synthesized V-doped NiSe2 nanowire arrays on pretreated nickel foam by a convenient two-step hydrothermal synthesis method. In the alkaline electrolyte, V-NiSe2/NF exhibited excellent OER catalytic activity (293.6 mV@50 mA cm–2). In addition, the introduction of heteroatom V induces stronger electronic interactions between the structural atoms of the catalyst, altering the electronic structure and causing V-NiSe2/NF to demonstrate excellent OER performance. In the long-term OER test, V-NiSe2/NF was converted into NiOOH and SeOx2–, which may be the “real” active species during catalytic reactions, and we also successfully captured the formation of intermediate NiOOH and selenite as active centers in the OER process through in-situ Raman. The theoretical calculation shows that the electron transfer modulates the electron structure, changes the adsorption-desorption energy of the reaction intermediates, reduces the potential barrier of the rate-limiting step, and improves the OER activity. The V doping engineering strategy and the unique nanowire array structure make TMSes exhibit excellent OER performance. This study provides a new idea for the design of TMSe catalysts with excellent electrocatalytic performance.

Effect of molybdenum valence in low Mo/Sn ratio catalysts for the oxidation of methanol to dimethoxymethane

A series of Mo/Sn (1:20, molar ratio) catalysts were prepared by two-step hydrothermal synthesis method, and the effect of calcination temperature of tin precursors on the reaction performance of methanol oxidation to dimethoxymethane (DMM) was investigated. The crystal structure, surface properties, redox property and valence change of molybdenum species of the catalyst were characterized by XRD, Raman, FT-IR, XPS, NH3-TPD and H2-TPR. The results showed that Mo1Sn20-600°CSn catalyst exhibited better performance than other catalysts, achieving DMM selectivity of 90% with methanol conversion of 30% at 140 °C. From the characterization results, the surface properties of the tin precursors affected the structure of catalyst, the degree of molybdenum oxide dispersion and valence of molybdenum species, and further influenced the performance of the catalysts. The high temperature calcination of tin precursors is more favorable for the generation of Mo6+ in the Mo1Sn20 catalyst.

CTAB improves the performance of NiMoO4@NF grown NiCoZn-LDH for supercapacitor

Transition metal hydroxides have attracted wide attention as promising composite nanomaterials due to their numerous active sites and large specific surface areas. In this study, a two-step hydrothermal synthesis method is proposed to generate a heterostructure (NiCoZn-LDH@NiMoO4@NF) consisting of nanoflowers coated with nanoneedles on a foam nickel substrate. The aggregation issue of NiCoZn-LDH is effectively improved by immersing it in CTAB solution after one-step hydrothermal synthesis of NiMoO4 nanoneedles on Ni Foam (NF). The heterostructure between NiMoO4 nanoneedles and NiCoZn-LDH significantly enhances the material stability and electrochemical performance. Activated carbon is used as the negative electrode, and the NiCoZn-LDH@NiMoO4@NF composite material is used as the positive electrode to assemble an asymmetric supercapacitor (ASC) device for electrochemical testing. The device exhibits a specific capacitance of 3541 mF/cm2 at a current density of 6 mA/cm2. Furthermore, the capacity retention rate remains at 83.04 % after 10,000 cycles of charge and discharge, and a high specific energy density of 0.735 mWh/cm2 is achieved at a power density of 1.6 mW/cm2. The experimental results demonstrate that transition metal hydroxides play a crucial role in enhancing the electrochemical performance of supercapacitors. This study provides new insights into Supercapacitor (SC) active materials and offers a promising experimental approach for synthesizing new nanomaterials.

Active Site Engineering and Theoretical Aspects of "Superhydrophilic" Nanostructure Array Enabling Efficient Overall Water Electrolysis.

The rational design of noble metal-free electrocatalysts holds great promise for cost-effective green hydrogen generation through water electrolysis. In this context, here, the development of a superhydrophilic bifunctional electrocatalyst that facilitates both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline conditions is demonstrated. This is achieved through the in situ growth of hierarchical NiMoO4 @CoMoO4 ·xH2 O nanostructure on nickel foam (NF) via a two-step hydrothermal synthesis method. NiMoO4 @CoMoO4 ·xH2 O/NF facilitates OER and HER at the overpotentials of 180 and 220mV, respectively, at the current density of 10mA cm-2 . The NiMoO4 @CoMoO4 ·xH2 O/NF ǁ NiMoO4 @CoMoO4 ·xH2 O/NF cell can be operated at a potential of 1.60V compared to 1.63V displayed by the system based on the Pt/C@NFǁRuO2 @NF standard electrode pair configuration at 10mA cm-2 for overall water splitting. The density functional theory calculations for the OER process elucidate that the lowest ΔG of NiMoO4 @CoMoO4 compared to both Ni and NiMoO4 is due to the presence of Co in the OER catalytic site and its synergistic interaction with NiMoO4 . The preparative strategy and mechanistic understanding make the windows open for the large-scale production of the robust and less expensive electrode material for the overall water electrolysis.

High-throughput synthesis and phase transition characteristics controlling of VO2(M) nanoparticles via an orthogonal optimization route

Thermochromic behaviors of VO2(M) are affected significantly by the size purity, and crystallinity of the particles, and it needs a mass of experiments to adjust the factors suitably. Herein, an orthogonal array design (OAD) [L9 (34)] was applied to select the optimum conditions for high-throughput preparation of VO2(M) nanoparticles with controllable morphology and size. The effects of fill ratio, reaction time, annealing time, and annealing temperature on the size of VO2(M) nanoparticles were evaluated by OAD. These results showed that the factors for the size arranged as follows: fill ratio > reaction time > annealing time > annealing temperature. The validation of optimized experimental parameters proved that pure VO2(M) nanoparticles with a diameter of ∼60 nm were prepared in this work. Therefore, the high-throughput preparation of VO2(M) nanoparticles with small size was achieved via an optimized two-step hydrothermal synthesis method, which can support the large-scale applications of VO2(M) nanoparticles in smart windows and optical switches.

Controlled synthesis of M doped N-Ni3S2 (M = Cu, Fe, Co and Ce) on Ni foam as efficient electrocatalyst for urea oxidation reaction and oxygen evolution reaction

Replacing fossil fuels by electrocatalytic water splitting for producing hydrogen and oxygen is one of the most promising ways to solve the energy crisis and environmental pollution. In this work, a series of M doped N-Ni 3 S 2 (M = Cu, Fe, Co and Ce) material was firstly synthesized and in situ grown on nickel foam substrate by a typical two-step hydrothermal synthesis method. Two probe reactions, water oxidation and urea oxidation, were selected to investigate the catalytic performance of these materials. What is noteworthy is that the Fe doped N-Ni 3 S 2 material exhibits superior water oxidation properties with requiring only 270 mV of overpotentials to drive current densities of 100 mA cm −2 , which is one of the best activities reported so far. After a long time of durability measurement, the current density of the Fe doped N-Ni 3 S 2 material will be attenuated, suggesting that the surface of the material will be in situ oxidized to oxide or hydroxide, which is the true active species. For urea oxidation, the Co doped N-Ni 3 S 2 material shows superior catalytic performance with requiring only 1.36 V potentials to drive 100 mA cm −2 current densities. Density functional theory (DFT) calculation shows that different adsorption energy of water for N-Ni 3 S 2 , N-Cu-Ni 3 S 2 , N-Fe-Ni 3 S 2 and N-Co-Ni 3 S 2 leads to the different catalytic activity. Experimental results demonstrate that the improved catalytic performance is assigned to faster electron transfer rates, exposure of abundant active center and better conductivity due to N and cation doping. This work provides new lessons for doping engineering for water splitting reactions. Fe doped N-Ni 3 S 2 material exhibits superior water oxidation properties, requiring only 270 mV of overpotentials to drive current densities of 100 mA cm −2 . • Fe and N ion co-doped Ni 3 S 2 nanoarrays were prepared by typical hydrothermal processes. • The Fe-N-Ni 3 S 2 presents an improved activity with small overpotentials of 270 mV for water oxidation. • The Co-N-Ni 3 S 2 presents an improved activity with potentials of 1.36 V for urea oxidation.

Synthesis and characterization of sensitive molecularly imprinting electrochemical sensor based on chitosan modified aminoated hierarchical porous silica-supported gold for detection of 2, 4-dichlorophenoxyacetic acid

In this work, a sensitive electrochemical sensor based on chitosan modified aminoated hierarchical porous silica-supported gold (CS-HPSNs-NH2@Au) and molecularly imprinted polymers (MIPs) film for detection of 2, 4-dichlorophenoxyacetic acid (2, 4-D) was prepared. The HPSNs-NH2@Au was synthesized by two-step hydrothermal synthesis method. The MIPs film, consisting of the template molecule of 2, 4-D and the functional monomer of o-phenylenediamine (o-PD), was electropolymerized onto the surface of glassy carbon electrode (GEC) modified by CS-HPSNs-NH2@Au. The porous structure of HPSNs-NH2@Au provides more imprinting recognition sites for template molecule, while the synergistic effect of fluffy HPSNs-NH2 and gold nanoparticles can effectively facilitate electron transfer. The specific surface area and electrical conductivity endow HPSNs-NH2@Au with a series of electrochemical properties, which confirms the uniqueness of nanocomposite and enhances current response. Chitosan can enhance the mechanical strength of the films, and prevent HPSNs-NH2@Au from falling off. MIPs combinded with electrochemical sensor have good sensitivity for 2, 4-D detection. Under optimized conditions, The prepared MIPs/CS-HPSNs-NH2@Au sensor showed significant detection performance with 2, 4-D in the range of 10−4 to 10−11 mol L−1 and the LOD was 6.077 × 10−12 mol L−1 (S/N = 3). Furthermore, the sensor has excellent selectivity in the presence of interfering substances and it was successfully determined 2, 4-D in three samples.

Flower-like Mo doped Ni(OH)2@Co3S4-Ni3S2 heterostructure for asymmetric supercapacitors

The construction of heterostructures is a common means for obtaining new high-performance materials. On this basis, doping of metallic elements tends to achieve surprising expectations. Here, Ni(OH)2@Co3S4-Mo-Ni3S2 heterostructures were obtained by doping molybdenum into cobalt sulfide layers through a facile two-step hydrothermal synthesis method. Impressively, the doping of Mo also affected the Ni-O bond interaction, and this cross-component synergistic effect led to the generation of defects and triggered an overall improvement in the properties of the original Ni(OH)2@Co3S4-Ni3S2 material. The results showed that the specific surface area increased from 24.4 m2/g to 53.8 m2/g after Mo doping, and the Ni(OH)2@Co3S4-Mo-Ni3S2 electrode exhibited twice the specific capacitance (2869: 1360 F g–1 = 2.1) at a current of 2 A g–1. Likewise, after 5000 cycles, the capacitance retention of the Ni(OH)2@Co3S4-Mo-Ni3S2 electrode was 86.7%, better than the 82.5% before doping. To further explore its practicality, the Ni(OH)2@Co3S4-Mo-Ni3S2//AC ACS device was assembled, delivering a maximum energy density of 56.2 W h kg–1 at a power density of 213.4 W kg–1 and showing good cycling stability (91.2% capacitance retention after 5000 cycles). This work demonstrates that Mo doping for modification of heterostructures to further improve performance is a feasible and prospective approach.

The construction of three-dimensional CdIn2S4/MoS2 composite materials for efficient hydrogen production

In this study, CdIn2S4/MoS2 composite structure was prepared by a simple two-step hydrothermal synthesis method, and the CdIn2S4/MoS2 composite structure samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectroscopy (UV–vis). Due to the effective loading of MoS2 on the surface of CdIn2S4 particles, the photocatalytic performance of CdIn2S4/MoS2 composite material is significantly improved under visible light irradiation (λ = 420 nm), which indicating the effective inhibit the recombination of photogenerated electron holes. Meanwhile, the visible light response of CdIn2S4 is increased and the life of photoexcitation carrier is prolonged. The CdIn2S4/MoS2 (sample 2CM) composite sample with mole content of 9% has the highest catalytic hydrogen production activity, and its hydrogen production rate is 293 μmol h−1 g−1, which is more than 3 times that of sample C. After 4 cycles of photocatalytic experiments, the photocatalytic activity is still stable, and the XRD diffraction peak does not appear obvious shift, which provides a new way for the design and preparation of efficient and stable photocatalytic materials.

Fabrication of trimodal porous silica/g-C[formula omitted]N[formula omitted] nanotubes for efficient visible light photocatalytic reduction of CO[formula omitted] to ethanol

The novel composite photocatalyst of trimodal porous silica (TPS)/g-C3N4 nanotubes was fabricated via a two-step hydrothermal synthesis method with intermediate pretreatment. The TPS was extracted from rice husk, which is agricultural waste, to further reduce the cost of photocatalyst preparation. A series of characterization results, including X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, N2 adsorption–desorption, and pore size analysis, illustrated the properties of crystal, pore structure, and morphology of the composite photocatalyst. The TPS/g-C3N4 presented a hollow tubular shape with a large surface area and CO2 adsorption capacity, so there were more catalytic active reaction sites. The photocatalytic activity measurement was operated, and only ethanol was detected when g-C3N4 NT and composite TGNT were used as photocatalysts. In particular, the ethanol yield of TGNT2 was 196μm/g, and after 10 cycles of running, the photocatalytic activity decreased by less than 5%. UV–Vis diffuse reflectance spectra, photoluminescence spectra, and photoelectrochemical analysis revealed the mechanism of the photocatalytic activity enhancement from the aspects of visible light absorption, photo-generated electron–hole pair separation and transfer, and charges recombination. It theoretically explained the prospect of this fabrication strategy. It demonstrated that TGNT is a low-cost, stable, efficient, and promising photocatalyst to reduce CO2 to ethanol under visible light.

A novel sensitive ACNTs-MoO2 SERS substrate boosted by synergistic enhancement effect.

Integrating chemical enhancement (CM) and electromagnetic enhancement (EM) into one substrate is of great significance, but as far as we know, little research has been done on this project. In this paper, the novel bead chain like acidified carbon nanotubes-MoO2 (ACNTs-M) were designed by a simple two-step hydrothermal synthesis method. Benefitting from a good adsorption capacity, chemical enhancement and surface electromagnetic field enhancement effect, ACNTs-M exhibits a stunning SERS performance. The maximum enhancement factor (EF) of 5.13 × 107 is obtained with R6G molecules on ACNTs-M. The limit of detection (LOD) of R6G is 10-10 M. In addition, ACNTs-M also exhibits SERS sensitivity of other organic dyes (CV, RhB and MB). The results of Raman signal enhancement mechanism research verified that the synergy of CM and EM is the reason for the high SERS sensitivity of ACNTs-M. We believe that our work may bring cutting edge of development of stable and highly sensitive nonmetal SERS substrates.

Synthesis of Surfactant-Assisted C/Fe-FeVO₄ Nanostructure: Characterization and Photocatalytic Degradation of Ciprofloxacin.

The novel C/Fe-FeVO₄ composite photocatalyst were synthesized by using a two-step hydrothermal synthesis method. Through a detailed exploration on the chemical and phisical properties by some spectroscopic and analytical techniques, the as-prepared C/Fe-FeVO₄ exhibted a nanosheet and meso porosity structure. Accordingly, we further utilized this C/Fe-FeVO₄ composite as a photocatalist for degradating the notorious ciprofloxacin (CIP) under simulated solar light (SSL) irradiation. Due to its outstanding catalytic properties, the C/Fe-FeVO₄ exhibited superior photocatalytic activity. The possible photocatalytic mechanism has been discussed.

A two-step hydrothermal synthesis of CeO2/CdS nanocomposite for photovoltaic application: an investigation on surface morphology, structure, optical and electrical properties

CeO2 nanocrystals possess superior optical and electronic properties due to their unfilled electronic orbitals. However, the wide bandgap of CeO2 limits its application in the visible region. Therefore, we combined CdS with CeO2 for band gap engineering of the nanocomposite and to obtain enhanced optoelectronic properties. Spherical and rectangular shaped CeO2/CdS nanoparticles were prepared by a facile two-step hydrothermal synthesis method. The effects of altering molar concentrations of the precursors on the morphology, structure, optical and electrical properties of the nanocomposites were systematically studied. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDXA) were used to swot the structure, morphology, and composition of the CeO2/CdS nanoparticles, respectively. The average particle size and microstrain of the nanoparticles were estimated from the XRD peak widths. The estimated average crystallite size was found to be 6–13 nm for the CeO2/CdS nanocrystals. Raman and XPS spectra also confirmed the presence of different elemental composition in the nanocomposites. The optical properties were studied by UV-Visible diffused reflectance spectroscopy and Photoluminescence (PL) spectroscopy. The band gap values estimated for the synthesized CeO2/CdS nanocomposites were in the range of 2.34–2.39 eV. The nanocomposite sample with molar ratio Ce:Cd = 1:2, demonstrates the least reflectance in the visible light spectra. A blue emission band was observed at 473 nm in photoluminescence spectra. The vibrational modes were detected by Fourier Transform Infrared (FTIR) spectroscopy. The electrical properties of the CeO2/CdS nanoparticles were explicitly analyzed and the enhancement of current was observed under illumination. The stimulating optical and electrical properties of CeO2/CdS nanocomposites make it the most promising material for photoelectric devices and solar cell applications.

Two-Step Hydrothermal Synthesis of Well-Dispersed (Na0.5Bi0.5)TiO3 Spherical Powders

(Na0.5Bi0.5)TiO3 (NBT) powders that have well-dispersed, uniform particle size and well-developed spherical shape were successfully prepared by a two-step hydrothermal synthesis method. Nanosized TiO2 powders were firstly synthesized by a hydrothermal method, and then the TiO2 particles are used as a raw material to synthesize NBT powders. It was found that by using the TiO2 nanoparticles as Ti source, the well-dispersed spherical NBT powders with about 200 nm in size could be obtained at 200°C for 4 h with a low mineralizer concentration of 6 mol/L NaOH in the second step. The formation of spherical NBT powders can be explained by first generating nuclei on the surface of TiO2 nanoparticles via in situ crystallization mechanism and then crystal growing and agglomerating by dissolution-recrystallization mechanism.

Constructing magnetic Pt-loaded BiFeO3 nanocomposite for boosted visible light photocatalytic and antibacterial activities.

Visible light-responsive Pt-loaded coral-like BiFeO3 (Pt-BFO) nanocomposite at different Pt loadings was synthesized via a two-step hydrothermal synthesis method. The as-synthesized photocatalyst was characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminescence (PL) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and magnetic hysteresis loop (M-H loop) analyses. The FESEM images revealed that Pt nanoparticles were evenly distributed on the coral-like BFO. The UV-vis DRS results indicated that the addition of Pt dopant modified the optical properties of the BFO. The as-synthesized Pt-BFO nanocomposite was effectively applied for the photodegradation of malachite green (MG) dye under visible light irradiation. Specifically, 0.5wt% Pt-BFO nanocomposite presented boosted photocatalytic performance than those of the pure BFO and commercial TiO2. Such a remarkably improved photoactivity could be mainly attributed to the formation of good interface between Pt and BFO, which not only boosted the separation efficiency of charge carriers but also possessed great redox ability for significant photocatalytic reaction. Moreover, the strong magnetic property of the Pt-BFO nanocomposite was helpful in the particle separation along with its great recyclability. The radical scavenger test indicated that hole (h+), hydroxyl (·OH) radical, and hydrogen peroxide (H2O2) were the main oxidative species for the Pt-BFO photodegradation of MG. Finally, the Pt-BFO nanocomposite was revealed high antibacterial activity towards Bacillus cereus (B. cereus) and Escherichia coli (E. coli) microorganisms, highlighting its potential photocatalytic and antibacterial properties at different industrial and biomedical applications.

Constructing a novel Zn2SnO4/C/AgBr nanocomposite with extended spectral response and improved photocatalytic performance

High-efficient photocatalyst based on Zn2SnO4/C/AgBr multi-component heterostructure was prepared via a two-step hydrothermal synthesis method followed by chemical deposition process. Morphological studies showed that ultra-fine AgBr nanoparticles with the size of 3–5 nm were in situ grown on the surface of the carbon layers attached to Zn2SnO4 nanocrystals. UV–vis characterization demonstrated that the co-modification of carbon and AgBr contributed to the dramatically improved light absorption ability of Zn2SnO4/C/AgBr nanocomposites. In the multi-component heterostructured photocatalyst, carbon functioning as a charge mediator plays a pivotal role in separating photogenerated electron-hole pairs efficiently. Zn2SnO4/C/AgBr photocatalysts exhibited a significant enhancement of visible-light photocatalytic performance toward the photodegradation of rhodamine B (RhB), resulting from the synergistic effect of the intensified visible-light absorption capacity and efficient photogenerated electron-hole pairs transfer. In addition, a proposed schematic mechanism for the significant enhancement of photocatalytic performance is as well put forward on the basis of the experimental results.

ZnFe2O4/MoS2/rGO composite as an anode for rechargeable Lithium-ion batteries

The transition metal oxide ZnFe2O4 can be used as a promising anode material for lithium-ion batteries because of its higher theoretical capacity (1072 mA h g−1), and MoS2 has also received extensive attention because of its low cost and environmental friendliness. However, the expansion and contraction of the volume during charge and discharge limit the commercial application of ZnFe2O4 and MoS2. We synthesize ZnFe2O4/MoS2/reduced graphite oxide (ZnFe2O4/MoS2/rGO) ternary composite material by a simple two-step hydrothermal synthesis method and subsequent heat treatment. ZnFe2O4/MoS2/rGO displays a good electrochemical performance due to a synergistic effect of MoS2 with a three-dimensional spherical structure and rGO as a conductive agent. At a current density of 200 mA g−1, the discharge capacity still reaches 1568 mAh g−1 after 100 cycles. At the same time, high-rate performance is also good (638 mAh g−1 at 1800 mA g−1).

Synthesis of MoS2-TiO2 nanocomposite for enhanced photocatalytic and photoelectrochemical performance under visible light irradiation

In this work, we have prepared MoS2 nanoflakes modified TiO2 nanoparticles (MoS2-TiO2 nanocomposite) with varying concentration of MoS2 (2.5–10 wt.%) by a two-step hydrothermal synthesis method involving specific preparation conditions for the TiO2 nanoparticles and MoS2 nanoflakes. The prepared samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy (XPS) techniques. The photocatalytic activity of the pristine TiO2 nanoparticles and MoS2-TiO2 nanocomposite samples were evaluated by examining the photocatalytic degradation of Rhodamine B (RhB). The photoelectrochemical activity of these samples were measured by performing solar water splitting experiments under visible light irradiation. It was observed that the MoS2-TiO2 nanocomposite with 7.5 wt.% MoS2 exhibits highest photocatalytic and photoelectrochemical activity as it has the optimum amount of MoS2 nanoflakes which probably minimizes the recombination of photogenerated charge carriers as compared to other concentrations of MoS2 in MoS2-TiO2 nanocomposite and pristine TiO2 nanoparticles. In addition, a rather high photocatalytic reaction rate constant was observed for MoS2-TiO2 nanocomposite with 7.5 wt.% MoS2 nanoflakes.