Simple Solvothermal Technique Research Articles

Co/Ni/Cu-NH2BDC MOF@natural Egyptian zeolite ore nanocomposite for calcium ion removal in water softening applications.

Water softening is a treatment process required to remove calcium (Ca(II)) and magnesium (Mg(II)) cations from water streams. Nanocomposites can provide solutions for such multiple challenges and have high performance and low application costs. In this work, a multimetallic cobalt, nickel, and copper 2-aminoterephthalic acid metal-organic framework ((Co/Ni/Cu-NH2BDC) MOF) was synthesized by a simple solvothermal technique. This MOF was supported on an Egyptian natural zeolite ore and was used for the adsorption of Ca(II) ions for water-softening applications. The adsorbent was characterized using Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), N2 adsorption-desorption isotherms, and zeta potential measurements. The adsorption isotherm data for the prepared adsorbent toward Ca(II) were best fit using the Redlich-Peterson model and showed a maximum adsorption capacity of 88.1 mg/g. The adsorption kinetics revealed an equilibrium time of 10 min, which was best fit using the Avrami model. The intermolecular interactions of Ca(II) ions with zeolite and MOF were investigated by Monte Carlo simulations, molecular dynamics simulations, and FTIR and XRD analyses. The adsorption sites in the zeolite structure were oxygen atoms, while those in the MOF structure were amine nitrogen atoms. The Ca(II) ions are coordinated with the solvent molecules in both structures. Finally, the in vitro cytotoxicity of this nanocomposite was assessed, revealing viability levels of 74.57 ± 2.1% and 21 ± 2.79% for Vero and African green monkey kidney and human liver (HepG2) cells, respectively. Cytotoxicity assays help assess the environmental impact of these materials, ensuring that they do not harm aquatic organisms or disrupt ecosystems. Thus, this study demonstrated the valorization of MOF/zeolite as a valuable and industry-ready adsorbent that can appropriate Ca(II) contaminants from aqueous streams.

A novel mercapto-functionalized bimetallic Zn/Ni-MOF adsorbents for efficient removal of Hg(II) in wastewater

Heavy metals, especially mercury ions, pose extreme hazards to human health and environmental sustainability. Receiving significant interest lately, metal-organic frameworks with mercapto-functionalization (SH-MOFs) have shown impressive efficacy in effectively eliminating highly hazardous Hg(II) from wastewater. In this investigation, a novel mercapto-functionalized Zn/Ni bimetallic MOF (ZNM-2) was synthesized utilizing a simple solvothermal technique employing zinc and nickel as metal sources and 2-mercaptobenzimidazole (MBI) as the organic ligand. The Hg(II) adsorption capacity by ZNM-2 reached 744.4 mg/g, surpassing that of a single-nickel MOF (NM) 328.8 mg/g. More impressively, ZNM-2 successfully eliminated 99.99 % of Hg(II) from actual water samples, achieving a concentration level for Hg(II) that is lower than the threshold of 1.0 μg/L specified in the GB 5749–2022 drinking water standard. When the pH of Hg(II) solution ranged from 2.0 to 6.0, it exhibited exceptional adsorption capacity and sustained high removal efficiency throughout four consecutive regeneration cycles. The adsorption mechanisms observed in this study were found to conformity with the Langmuir model and PSO kinetic model, suggesting that the predominant mode of Hg(II) adsorption is through a chemisorption process occurring at a monolayer level. The superior Hg(II) removal rate of ZNM-2 can be attributed to the predominant coordination of Hg(II) to the thiol (-SH) groups, as revealed by a combination of FT-IR, XPS analysis, and DFT calculations. Therefore, ZNM-2 is an efficacious Hg(II) absorbent that provides a novel approach to alleviate mercury contamination in wastewater.

Strong magnetodielectric effect in Bi(La)Fe(Cr)O3 multiferroic nanomaterials

The Bi1-xLaxFe1-yCryO3 (x = 0.00, 0.06; y = 0.00, 0.03, 0.06, 0.09, 0.12) nanomaterials have been synthesized using the simple solvo-thermal technique. The Rietveld refinement of XRD analysis using FullProf Software confirms that all synthesized materials follow rhombohedral perovskite crystal structure of R3C space group. The dielectric and ac conductivity data are analyzed to understand the role of grain and grain boundary contributions. The enhancement of magnetic properties has been observed from SQUID measurement for the co-doped samples at room temperature. Also, a significant improvement in polarization has been observed for the doped nanocompounds from the ferroelectric hysteresis loop. The magneto-dielectric study reveals a large improvement in our co-doped BFO nanomaterials and the value is nearly three times of those reported earlier. The calculated energy storage efficiency for the co-doped samples are found to have as high as 51 %. The sample with x = 0.06 and y = 0.09 with a magneto dielectric coefficient of around 30 % and energy storage efficiency of 35 % is the most suitable for both spintronic and energy storage devices.

Electrochemical Nanosensor for the Simultaneous Determination of Anticancer Drugs Epirubicin and Topotecan Using UiO-66-NH2/GO Nanocomposite Modified Electrode.

In this work, UiO-66-NH2/GO nanocomposite was prepared using a simple solvothermal technique, and its structure and morphology were characterized using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). An enhanced electrochemical sensor for the detection of epirubicin (EP) was proposed, which utilized a UiO-66-NH2/GO nanocomposite-modified screen-printed graphite electrode (UiO-66-NH2/GO/SPGE). The prepared UiO-66-NH2/GO nanocomposite improved the electrochemical performance of the SPGE towards the redox reaction of EP. Under optimized experimental conditions, this sensor demonstrates a remarkable limit of detection (LOD) of 0.003 µM and a linear dynamic range from 0.008 to 200.0 µM, providing a highly capable platform for sensing EP. Furthermore, the simultaneous electro-catalytic oxidation of EP and topotecan (TP) was investigated at the UiO-66-NH2/GO/SPGE surface utilizing differential pulse voltammetry (DPV). DPV measurements revealed the presence of two distinct oxidation peaks of EP and TP, with a peak potential separation of 200 mV. Finally, the UiO-66-NH2/GO/SPGE sensor was successfully utilized for the quantitative analysis of EP and TP in pharmaceutical injection, yielding highly satisfactory results.

Ni-Based Catalysts for CO2 Methanation: Exploring the Support Role in Structure-Activity Relationships.

The catalytic hydrogenation of CO2 to methane is one of the highly researched areas for the production of chemical fuels. The activity of catalyst is largely affected by support type and metal-support interaction deriving from the special method during catalyst preparation. Hence, we employed a simple solvothermal technique to synthesize Ni-based catalysts with different supports and studied the support role (CeO2, Al2O3, ZrO2, and La2O3) on structure-activity relationships in CO2 methanation. It is found that catalyst morphology can be altered by only changing the support precursors during synthesis, and therefore their catalytic behaviours were significantly affected. The Ni/Al2O3 with a core-shell morphology prepared herein exhibited a higher activity than the catalyst prepared with a common wet impregnation method. To have a comprehensive understanding for structure-activity relationships, advanced characterization (e. g., synchrotron radiation-based XAS and photoionization mass spectrometry) and in-situ diffuse reflectance infrared Fourier transform spectroscopy experiments were conducted. This research opens an avenue to further delve into the role of support on morphologies that can greatly enhance catalytic activity during CO2 methanation.

Novel mixed heterovalent (Mo/Co)Ox-zerovalent Cu system as bi-functional electrocatalyst for overall water splitting

A novel hybrid ternary metallic electrocatalyst of amorphous Mo/Co oxides and crystallized Cu metal was deposited over Ni foam using a one-pot, simple, and scalable solvothermal technique. The chemical structure of the prepared ternary electrocatalyst was systematically characterized and confirmed via XRD, FTIR, EDS, and XPS analysis techniques. FESEM images of (Mo/Co)Ox–Cu@NF display the formation of 3D hierarchical structure with a particle size range of 3–5 µm. The developed (Mo/Co)Ox–Cu@NF ternary electrocatalyst exhibits the maximum activity with 188 mV and 410 mV overpotentials at 50 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. Electrochemical impedance spectroscopy (EIS) results for the (Mo/Co)Ox–Cu@NF sample demonstrate the minimum charge transfer resistance (Rct) and maximum constant phase element (CPE) values. A two-electrode cell based on the ternary electrocatalyst just needs a voltage of about 1.86 V at 50 mA cm−2 for overall water splitting (OWS). The electrocatalyst shows satisfactory durability during the OWS for 24 h at 10 mA cm−2 with an increase of only 33 mV in the cell potential.

Reduced graphene oxide/ Sr2Co2O5 composites as electrode material for supercapacitors

Composites of transition metal-oxides with graphene have grown as potential materials for electrodes, for supercapacitor applications. In this work, Sr2Co2O5 with different percentages of reduced graphene oxide (rGO) (0–15 %) has been prepared by a simple solvothermal technique. The electrochemical performance of composites is examined in comparison with pure Sr2Co2O5. Structural analysis exhibited the orthorhombic structure of Sr2Co2O5 whereas the morphological investigations revealed a variety of morphology for different compositions. The presence of all elements in the parent and derived compositions according to their stochiometric formula is ascertained by energy dispersive X-ray spectroscope. The investigations of electrochemical characteristics revealed the dominant pseudocapacitance behavior in the cyclic voltammetry technique. The value of specific capacitance, energy density, and power density are computed from GCD data. The Sr2Co2O5@15%rGO exposes the highest specific-capacitance of 230.95 F/g at the current density of 0.625 A/g, and high energy and power densities having values of 76.58 Wh/kg and 4.94 W/kg respectively at 12.5 A/g. The solution resistance and ion transportation resistance are examined through electrochemical impedance spectroscopy which exhibits the potential of these composites for supercapacitor electrode material.

Enhancing the visible light absorption of MOF-808 by surface decoration with sulfur and nitrogen co-doped carbon quantum dots: Highly efficient photocatalyst for improved photocatalytic water remediation

Metal-organic frameworks (MOFs) have aroused growing attention in the domain of photocatalysis. However, the photocatalytic performance of MOFs has been severely restricted by their fast recombination of photo-generated electrons and low utilization of solar energy. Combining MOFs with narrow-gap semiconductors can help to overcome their functional shortcomings. In this work, MOF-808 and sulfur and nitrogen co-doped carbon quantum dots (S,N-CQDs) were synthesized using a simple solvothermal technique. Then, novel MOF-808/S,N-CQDs(x) (MS-x) composites were fabricated through a simple solvent-deposition technique to decorate various amounts of S,N-CQDs on the surface of MOF-808. The morphology of MOF-808 and MS-0.5 composite, along with the lattice spacing, and size distribution of decorated S,N-CQDs on MOF-808 surface were investigated by SEM and HR-TEM analyses. According to the UV–Vis DRS and Tauc plots findings, MOF-808 was not photo-active in visible light region because of its large band gap energy (3.85 eV). In contrast, the photocatalytic performance of the prepared composites in Rhodamine B (RhB) degradation was significantly enhanced compared with MOF-808 under visible light irradiation. The results confirmed that S,N-CQDs play a key role in enhancing the visible light absorption efficiency. MS-0.5 composite exhibited the highest photocatalytic activity among the other composites and demonstrated high RhB photodegradation up to 89 % under visible light and 95 % under sunlight irradiation in optimal conditions. According to the kinetic studies, MS-0.5 composite had the highest rate constant, 29.67 and 6.93 times greater than S,N-CQDs and MOF-808, respectively. The scavenger tests revealed that h+ and OH radicals were the main active intermediates in the photocatalytic reaction. In addition, MS-0.5 composite exhibited excellent reusability because only a minor loss of photoactivity was observed after four reaction cycles.

Binary metal oxide (NiO/SnO2) composite with electrochemical bifunction: Detection of neuro transmitting drug and catalysis for hydrogen evolution reaction

The synergetic effect between dual oxides in binary metal oxides (BMO) makes them promising electrode materials for the detection of toxic chemicals, and biological compounds. In addition, the interaction between the cations and anions of diverse metals in BMO tends to create more oxygen vacancies which are beneficial for energy storage devices. However, specifically targeted synthesis of BMO is still arduous. In this work, we prepared a nickel oxide/tin oxide composite (NiO/SnO2) through a simple solvothermal technique. The crystallinity, specific surface area, and morphology were fully characterized. The synthesized BMO is used as a bifunctional electrocatalyst for the electrochemical detection of dopamine (DPA) and for the hydrogen evolution reaction (HER). As expected, the active metals in the NiO/SnO2 composite afforded a higher redox current at a reduced redox potential with a nanomolar level detection limit (4 nm) and excellent selectivity. Moreover, a better recovery rate is achieved in the real-time detection of DPA in human urine and DPA injection solution. Compared to other metal oxides, NiO/SnO2 composite afforded lower overpotential (157 mV @10 mA cm−2), Tafel slope (155 mV dec−1), and long-term durability, with a minimum retention rate. These studies conclude that NiO/SnO2 composite can act as a suitable electrode modifier for electrochemical sensing and the HER.

Duple charge separation and plasmonically enriched DSSC and piezo-photocatalytic efficacy of Au anchored perovskite Gd3+:BiFeO3 nanospheres

Enhancing the solar-physical conversion efficacy ability of the nanomaterials is an essential for real-time implementation. We report the enhanced solar-physical efficiency of the BiFeO3 nanospheres via Gd3+ doping and Au nanoparticles decoration. Initially, we have obtained the Bi1-xGdxFeO3 nanospheres were attained via a simple solvothermal technique and then citrate reduction of Au was conducted. Obtained perovskite BiFeO systems were studied for the Gd3+ doping, crystalline phase and elemental purity using the XRD and XPS techniques. Transmission electron microscope had revealed the ∼400 nm sized BiFeO3 nanospheres. Optical absorption spectrum revealed the enhanced visible photon absorption occurring in BiFeO3 for both Gd3+ doping and Au decoration. The bandgap values of pristine, 1%, 3% and 5% Gd3+ doped in BiFeO3 are 2.2 eV, 2.19 eV, 2.17 eV and 2.12 eV, respectively. Conducted photoluminescence revealed the dual electron trapping occurring in BiFeO3 via Gd3+ ions and Au nanoparticles. LED light assisted 72% of piezo-photocatalytic degradation efficiency of Tetracycline is achieved with Bi0 95Fe0 05O3/Au, whereas the photo catalytic is only 65% and piezo catalytic efficiency is 58%. In recyclable studies the Bi0.95Gd0.05FeO3/Au had shown the consistent piezo-photocatalytic efficiency for 3 reaction cycles. Further, fabricated DSSC studies revealed that near 30 % enhanced solar photovoltaic efficiency for Bi0 95Fe0 05O3/Au (η = 6.5%) solar cells on par to the pristine BiFeO3 (η = 5.02%).

Metal-organic frameworks-derived Al/Mo co-doped porous Co3O4 hollow tetrahedrons for efficient triethylamine detection

Three-dimensional (3D) hollow porous structures have attracted great attention in surface-related fields due to their advantages such as large specific surface area, high gas permeability, and low agglomeration. In this work, Al/Mo co-doped porous Co3O4 hollow tetrahedrons derived from MOFs have been obtained using a simple solvothermal synthetic technique. Various characterizations have been used to analyze the crystalline and electronic structure. The results indicate that Al/Mo ions are successfully doped into the Co3O4 lattice and 0.2 at% Al/Mo co-doped Co3O4 shows the best sensing properties among the other Co3O4 based samples. In particular, 0.2% Al/Mo-Co3O4 exhibits the highest response values of 132–100 ppm TEA at 160 °C, which are 33 times as high as those of undoped Co3O4. Furthermore, 0.2% Al/Mo-Co3O4 also displays rapid response and recovery speed (4 s/36 s), low detection limit (0.5 ppm), good selectivity and long-term stability. The reason of enhanced TEA sensing properties is ascribed to the occurrence of 3D hollow porous structure and coupling effect of Al/Mo co-doping. Thus, 0.2 at% Al/Mo co-doped porous Co3O4 hollow tetrahedrons show promising applications in constructing high-performance chemical sensors for TEA detection.

MOF-derived porous NiCo2O4 nanofile arrays as an efficient anode material for rechargeable Li-ion batteries

Due to their vast surface area and superior porosity structure, metal-organic frameworks (MOFs) derived materials have recently presented a significant promise for better lithium-ion batteries (LIBs). Herein, we synthesised MOF-derived porous NiCo2O4 nanofile arrays from a simple solvothermal technique followed by calcination at 450 °C. The prepared sample was characterized by X-ray diffraction, thermogravimetric, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller. The acquired nanofile array morphology achieved a large specific surface area of 189 m2/g can shorten the Li ions (Li+) transport and enhance the electrochemical performance. As expected, the prepared electrode reveals a discharge-specific capacity of around 1120 mAh/g at a 0.1 C rate. At 2 C rate, the electrode's specific capacity can still reach 210 mAh/g after 100 cycles. The pseudocapacitive nature of NiCo2O4 was determined by kinetic analysis, revealing the diffusion-controlled faradaic behaviour. Our prepared electrode material is considered an attractive option for the anode material in rechargeable Li-ion batteries because it has been proven to have a relatively good specific capacity and cycling stability.

Physicochemical properties and AC magnetic field induced heating properties of solvothermally prepared thiospinel: Fe3S4 (greigite) nanoparticles

The presence of greigite (Fe3S4) nanoparticles in bacterial magnetosomes, and its lower toxicity have emerged as favourable aspects for its potential applications in various bio-medical applications, including magnetic hyperthermia. Despite having a number of intriguing features, systematic research on the heating efficiency of Fe3S4 nanoparticles (MNPs) in an AC magnetic field is scarce, which is primarily due to the difficulties in preparing phase pure greigite MNPs. In this study, greigite MNPs are prepared using a solvothermal approach, utilizing ethylene glycol as a solvent, and surface functionalized with varied concentrations of poly vinyl alcohol (PVA). Studies using powder x-ray diffraction and electron microscopy demonstrate the development of crystalline Fe3S4 MNPs (average crystallite size: 19–23 nm) with flaky or flower-like morphology. X-ray photoelectron spectroscopy indicates that the lattice is composed primarily of iron and sulphur. The existence of bio-compatible PVA polymer on the surface of the coated MNPs is confirmed using Fourier transform infrared spectroscopy. For the uncoated MNPs, the magnetization at 90 kOe and the effective anisotropy energy density values are found to be ∼ 15.2 emu g−1 and ∼ 22.3 kJ m−3, respectively. Due to the improved colloidal stability, magneto-calorimetric experiments reveal higher AC magnetic field induced heating efficiency for the PVA-coated MNPs. The highest specific absorption rate (SAR) is obtained as ∼ 67.8 ± 2.6 W/gFe in the current study, which is several times higher than the previously published values for synthetic Fe3S4 MNPs. Furthermore, for samples with comparable saturation magnetization and crystallite size, SAR is found to increase with initial susceptibility. The in vitro cytotoxicity studies show good bio-compatibility for the prepared greigite MNPs. The experimental findings provide deeper insights into the preparation of Fe3S4 MNPs using a simple solvothermal technique, and its AC magnetic field induced heating efficiency.

Synthesis and characterization of ternary NiO@Bi2MoO6–MoS heterojunction with enhanced photodegradation efficiency towards indigo carmine dye

Heterojunctions and metal oxide dopants are commonly used in binary and ternary nanocomposites to enhance photo degradability and maintain metal-free properties. This work describes the preparation of a novel NiO@Bi2MoO6–MoS complex ternary heterostructure using a simple solvothermal technique that possesses excellent photo activities for the removal of toxic Indigo carmine (InCa) dye from wastewater using a visible-illumination source. The prepared composites were characterized using various physicochemical techniques such as UV–Visible spectra, X-ray diffraction (XRD) techniques, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transforms infrared (FTIR) spectroscopy, elemental disperse X-ray (EDX) analysis, BET surface area, photoluminescence (PL), electron spin resonance (ESR) spectroscopy, and LC-MS analysis. The UV–Visible spectrophotometer confirmed that the absorption performance of the ternary NiO@Bi2MoO6–MoS composite is comprehensive in the visible light regions. NiO@Bi2MoO6–MoS exhibited the characteristic diffraction peaks of NiO and Bi2MoO6–MoS with a band gap energy (Eg) of 3.03 eV. SEM images confirmed that the synthesized composites show good phase confirmation, with particle sizes of ∼25 nm and morphologies of nanoflakes (Bi2MoO6–MoS) and nanorods (NiO@Bi2MoO6–MoS). The PL intensity of NiO@Bi2MoO6–MoS is much lower than that of Bi2MoO6 and Bi2MoO6–MoS composites, indicating a much more effective separation of photo-generated electrons and holes at the interface which in turn leads to the expected photocatalytic performance. The photocatalytic activity results showed that the degradation efficiency of NiO@Bi2MoO6–MoS for InCa dyes was 98.8%within 120 min, which is significantly superior to the binary composite Bi2MoO6–MoS (73.2%).The enhanced photo degradability of NiO@Bi2MoO6–MoSis a result of the hierarchical superstructure, enhanced visible light absorption, efficient charge transfer, and synergistic interaction between NiO, MoS, and Bi2MoO6 nanoparticles. Synergistic adsorption, effective double Z-scheme, and S-scheme mechanisms were efficient for the degradation of InCa dye into CO2, H2O, inorganic ions, and simpler products that showed excellent recyclability over five consecutive cycles.

Superior resistive switching performance in SnO2 nanoparticles embedded TiO2 nanorods-based thin films

Resistive random-access memories are ideal candidates for next-generation non-volatile memories due to their simple structure, fast response, and low power consumption. One-dimensional nanostructured memories are of particular importance owing to their electron transport confinement in individual components (such as nanorods/nanowires) that can provide extra control to finely tune the electrical performance for stable and reliable memory operations. In this work, vertically oriented one-dimensional TiO2 nanorods were fabricated via a simple and facile solvothermal technique. Besides, SnO2 nanoparticles were embedded on TiO2 nanorods matrix (to form a nanocomposite) and their resistive switching characteristics were evaluated and compared. Although, both devices expressed good resistive switching behavior. However, the nanocomposite device showed superior switching performance than the control (TiO2 nanorods) one. Moreover, the nanocomposite device demonstrated additional features of multilevel data storage and the prediction of switching probabilities at lower potentials to be applied in neuromorphic computing. The governing resistive switching mechanism was explored, and the role of oxygen vacancies was identified as critical for the switching and charge transport mechanism in the investigated devices.

Construction of various morphological ZnO-NiO S-scheme nanocomposites for photocatalytic dye degradation

The textile industry has a global environmental impact because of its discharge or dumping of wastewater into rivers, which has a significant impact on water resource quality. The removal of pollutant dyes from water using simple and efficient procedures is gaining interest worldwide. Hence, herein, a simple one-pot solvothermal technique is used to create various types of ZnO/NiO hierarchical nanostructures for photocatalytic dye degradation. Alcoholic solvents, such as ethanol, methanol, and propanol, were utilized for the formation of these nanostructures. The production of porous, marigold-like structures was observed through a morphological investigation. Appropriate characterization techniques were used to investigate the absorptivity, chemical composition, elemental state, crystallinity, and recombination rate. The porous flower-like structure with unique exciton acquisition demonstrated 82 % azo dye degradation, which was ∼ 3 and 2.5 times greater than those using pure ZnO and NiO structures, respectively. Reduced charge carrier recombination, rapid migration of produced electrons to the catalyst surface, and a mounted heterojunction across the interface contributed to this outstanding performance. Furthermore, the composite demonstrated remarkable reusability, retaining a dye degradation efficiency of 74 % after ten cycles. The nanostructure and remarkable dye-degrading capability of the synthesized composites demonstrate that they are suitable for photocatalysis applications.

Excellent photocatalytic performance and dual-band degradation of organic pollutants through Z-scheme photocatalysts

Organic pollutants, particularly nitrogen-rich explosives and carbon-rich dyes are generally degraded by different photocatalysts under either visible or ultraviolet light, leading to substantial waste and cost. Three photocatalysts with Z-scheme structures, Ag@AgBr/Cu2O-1, Ag@AgBr/Cu2O-2, and Ag@AgBr/Cu2O-3, are designed and synthesized employing a simple solvothermal and photoreduction technique to develop advanced photocatalyst materials that can degrade nitro substances under ultraviolet (UV) irradiation and organic dyes under visible-light irradiation. The structural characterization of Ag@AgBr/Cu2O-2 as determined through various spectroscopic techniques (e.g. XPS, XRD and TEM) reveal that the Z-scheme photocatalysts are composed of Ag, Cu2O and AgBr nanospheres with particle size less than 100 ​nm, while nano-Ag and nano-AgBr coupled to the surface of the Cu2O microspheres. Further investigations demonstrate that these photocatalysts exhibit a good UV–visible absorption range (200–800 ​nm) and outstanding photocatalytic degradation activity for two typical organic pollutants. Among them, Ag@AgBr/Cu2O-2 achieve a 100% degradation of trinitrotoluene (a common explosive) in 30 ​min under UV radiation, and a 99.2% degradation of rhodamine B (a typical dye) in 60 ​min under visible-light irradiation in the absence of UV light, demonstrating remarkable dual-band adaptability. Moreover, Ag@AgBr/Cu2O-2 displays superior stability, with a degradation rate of up to 85% after four cycles. The putative photocatalytic reaction mechanism is proposed based on the radical trapping experiment.

Morphological Perspective on Energy Storage Behavior of Cobalt Vanadium Oxide

AbstractCurrently available graphitic‐based anodes for lithium‐ion storage do not meet the present‐day energy requirements. Concerning the upcoming energy demands, it is necessary to discover high‐performance anode materials that are suitable for lithium‐ion energy storage systems. Herein, a CoV2O6 (cobalt vanadium oxide, cobalt vanadate denoted as CV) anode material using a simple solvothermal technique is synthesized. Furthermore, the effects of modifying the molar concentration of the precursor materials are investigated. Interestingly, there is no change in the crystal structure, but there is a morphological evolution in the materials. Due to the morphological variations, the electrochemical performances vary significantly. Among the synthesized materials, the CV‐2 compound performs the best, exhibiting excellent performance for lithium‐ion batteries as an anode. At the end of 500 cycles, the material delivers a specific discharge capacity of 391.03 mAh g−1 with a current density of 500 mA g−1.

A controllable flower-like FeMoO4/FeS2/Mo2S3 composite as efficient sulfur host for lithium-sulfur batteries

As one of the most anticipated energy storage systems, the application of lithium-sulfur batteries is hindered by low conductivity of insoluble sulfur species (S8, Li2S2 and Li2S), the shuttle effect of soluble lithium polysulfides (Li2Sx, 4 = x ≤ 8) and the volume expansion of sulfur species during the cycling. To overcome these barriers, a tunable geometry of flower-like FeMoO4/FeS2/Mo2S3 composite is successfully investigated using simple one-step solvothermal technique. Fe-based sulfides with good conductivity and Mo-based sulfides with the efficient ability of catalytic sulfur species conversion are promising sulfur host for high performance lithium-sulfur batteries (LSBs). It should be noted that this is first time to introduce FeMoO4 as polysulfides anchoring material into the lithium-sulfur system. Consequently, the flower-like composite with 79 wt % sulfur loading exhibits a high initial capacity of 1600 mA h g−1 and a reversible capacity of 781 mAh g−1 after 300 cycles at 1 C. Even at a high rate of 10 C, a capacity of 421 mAh g−1 is maintained after 300 cycles.

Tin oxide nanocatalyst assisted transformation of p-Nitrophenol to p-Aminophenol

We have successfully synthesized the SnO2 nanoparticles by using simple and inexpensive solvothermal technique. XRD pattern of as-synthesized product showed the formation of monophasic tetragonal SnO2 nanoparticles. The morphology of SnO2 was observed by FESEM which show irregular and rough shaped nanoparticles. Elemental and chemical composition analysis of SnO2 nanoparticles was carried out by EDAX analysis which confirms the presence of Sn and O in as-synthesized nanoparticles. The determination of specific surface area of as-synthesized SnO2 nanoparticles was done by BET method and it is found to be 35.5 m2/g. The optical properties of SnO2 nanoparticles were studied by using UV–Visible absorption spectroscopy which gives an optical band gap of 3.34 eV. The catalytic conversion of p-nitrophenol to p-aminophenol was performed to evaluate the efficiency of as-synthesized SnO2 nanoparticles as reducing catalyst. The catalytic reduction reaction was accomplished in presence of NaBH4 and water at room temperature. The observed investigations signpost that as-prepared SnO2 nanoparticles act as an effective nanocatalyst in the process of reduction.