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This study presents a novel approach to address synthetic dye pollution in wastewater by introducing a novel ZnO/CuO/Cu2MgO3 nanocomposite (NC) synthesized using a green method involving Common Rue plant extract. Through a series of meticulous experimental procedures, the synthesized materials exhibited remarkable properties. The ZnO/CuO/Cu2MgO3 NC exhibits a moderate band gap energy of 1.5 eV, confirming its semiconductor nature. XRD analysis revealed crystallite sizes of 29 nm. FTIR analysis provided insights into chemical compositions. SEM reveals well-defined, spherical nanocomposite particles. The research aims to investigate the photocatalytic degradation efficiency of this nanocomposite, with a focus on removing Bromocresol Green (BCG), a recalcitrant synthetic dye in wastewater. Photocatalytic degradation experiments demonstrate an impressive 99.66% BCG removal efficiency through adsorption within 75 min of solar irradiation with a rate constant of 0.091 min−1. The nanocomposites exhibited excellent recyclability, maintaining their photocatalytic activity over five consecutive cycles. This study introduces an eco-friendly nanocomposite and synthesis approach, offering a rapid and efficient solution for BCG degradation and addressing the challenges posed by synthetic dye pollutants in wastewater. [ABSTRACT FROM AUTHOR]

In the present research work, we have explored amperometric sensing properties of carbon nanospheres (Cx) (5%, 8%, and 15%) decorated over Sm2O3/Co3O4 nanocomposites (NC) that are synthesized by microwave-assisted method. The synthesized electrode materials are characterized by the techniques of X-ray diffraction (XRD), scanning electron microscopy (SEM), SEM-EDAX (energy-dispersive X-ray spectroscopy), BET (Brunauer–Emmett–Teller), XPS (X-ray photoelectron spectroscopy), and UV–visible. Phase analysis revealed mixed monoclinic crystal structure and crystallite size decreases from 32 to 22 nm. Plate/flake-like morphology resulted upon the incorporation of Cx on Sm2O3/Co3O4 crystal lattice. Redshift in the optical absorption peak resulted with an increase in Cx concentration on Sm2O3/Co3O4 NC and the optical band gap (Eg) decreases from 3.26 to 2.61 eV. The sensitive and selective determination of hydrogen peroxide (H2O2) is very important because it is a product of reactions catalyzed by oxidase enzymes, a powerful effector of redox signaling, versatile biomarker, and is widely used in the food industry. H2O2 is known to cause toxicity and they form hydroxyl radicals. The accurate detection of H2O2 can indicate the presence of enzyme activity, explosives, and cell signaling pathways. Additionally, H2O2 has become a signal propagator within signal amplification methodologies used to enhance selectivity of the diagnostic assays. The developed modified sensor (C15%:Sm2O3/Co3O4) showed amperometric detection of H2O2 with 96% steady current within 3–4 s, linear range was found to be 0.2 µM to 6 µM, limit of detection (LOD) 0.04 µM, and having a sensitivity of 0.483 µA/µM (R2 = 0.996). Further, sensitivity and selectivity were detected with glucose, dopamine, ascorbic acid, and uric acid at + 0.36 V and no current response was observed. The modified electrode material possess high selectivity, less response time, high stability, reusability, and high repeatability and can find applications in the field of real-time monitoring of hazardous materials, fabrication of biosensors, H2O2 sensors, and in optoelectronics. [ABSTRACT FROM AUTHOR]

Pollution of water has become the main problem around the world; chromium (Cr) has several industrial applications. However, Cr is considered very toxic pollutant, because of its carcinogenicity and high toxicity. The existing methods for the treatment of heavy metals are not economical, difficult to operate, and not eco-friendly. The biosorption process is easy to operate, cost effective as well as eco-friendly for the elimination of the toxic metal. In the present work, a zirconium oxide/date stones biochar bio-nanocomposite (ZrO2BNC) was utilized as low-cost biosorbent to remove the toxic Cr (VI). The modification of the activated bio-nanocomposite was confirmed using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), UV–Vis and Fourier-transform infrared (FTIR) spectroscopy. Optimized condition of various parameters for removal of chromium ion by zirconium oxide bio-nanocomposite (ZrO2BNC) was observed at the pH = 5, contact time 120 min, initial concentration 100 ppm, while 0.1 g sorbent dose. The results showed that the sorption process optimally correlated with Langmuir and 1st kinetic models with R2 value of 0.999. The percentage removal of Cr (VI) ions was checked by atomic absorbance spectrophotometer subsequently before and after the process of adsorption. These findings demonstrated that produced ZrO2BNC can be a cost effective, potential, and novel adsorbent for removel of contaminated chromium metal ions from the aqueous environment. [ABSTRACT FROM AUTHOR]

In this study, zinc vanadate/reduced graphene oxide (Zn3V2O8/rGO) composite has been synthesized via a simple approach. Advanced characterization techniques (powder X-ray, scanning electron microscopy, energy dispersive X-ray spectroscopy and ultraviolet-visible (UV-vis) spectroscopy) have been used to authenticate the formation of Zn3V2O8/rGO composite. Subsequently, Zn3V2O8/rGO was applied as photo-catalyst for hydrogen generation using photo-catalysis. The Zn3V2O8/rGO photo-catalyst exhibited a good hydrogen generation amount of 104.6 µmolg−1. The Zn3V2O8/rGO composite also demonstrates excellent cyclic stability which indicated better reusability of the photo-catalyst (Zn3V2O8/rGO). This work proposes a new photo-catalyst for H2 production application. We believe that the presence of synergistic interactions was responsible for the improved photo-catalytic properties of Zn3V2O8/rGO composite. The Zn3V2O8/rGO composite is an environmentally friendly and cost-effective photo-catalyst and can be used for photo-catalytic applications. [ABSTRACT FROM AUTHOR]

Z-scheme photocatalytic reaction is considered an effective strategy to promote the photogenerated electron-hole separation for significantly improving the efficiency of photocatalytic hydrogen precipitation from splitting water. In this study, a heterojunction nanocomposite material based on Zn3V2O8 (ZV) with MWCNT was prepared by a hydrothermal process. The photocatalysts were characterized by X-ray diffraction, scanning electron microscopy (SEM), Fourier transform infrared (FTIR), UV-visible absorption spectroscopy, and transmission electron microscopy (TEM) to understand crystal structure, morphology, and optical properties. The efficiency of the samples was evaluated for the photocatalytic H2 production under visible solar radiation using water glycerol as a sacrificial reagent. The obtained results suggest that, between ZV and ZV@MWCNT, the latter shows higher efficiency for H2 production. The maximum H2 production efficiency was found to be 26.87 μmol g−1 h−1 for ZV and 99.55 μmol g−1 h−1 for ZV@MWCNT. The synergistic effect of MWCNT to ZV resulted in improving the efficiency of charges and light-absorbing capacity, resulting in enhanced H2 production in the heterojunction nanocomposite material. The nanocomposite was stable and highly efficient for H2 production of six or more cycles. Based on the outcomes of this study, it can be observed that forming the heterojunction of individual nano systems could result in more efficient material for H2 production under visible solar energy. [ABSTRACT FROM AUTHOR]

In the present study, pristine ZnWO4, CoWO4, and mixed metal Zn0.5Co0.5WO4 were synthesized through the hydrothermal process using a Teflon-lined autoclave at 180 ℃. The synthesized nanomaterials were characterized by various spectroscopic techniques, such as TEM, FTIR, UV–vis, XRD, and SEM-EDX-mapping to confirm the formation of nanocomposite material. The synthesized materials were explored as photocatalysts for the degradation of xylenol orange (XO) under a visible light source and a comparative study was explored to check the efficiency of the bimetallic co-doped nanocomposite to the pristine metal tungstate NPs. XRD analysis proved that reinforcement of Co2+ in ZnWO4 lattice results in a reduction in interplanar distance from 0.203 nm to 0.185 nm, which is reflected in its crystallite size, which reduced from 32 nm to 24 nm. Contraction in crystallite size reflects on the optical properties as the energy bandgap of ZnWO4 reduced from 3.49 eV to 3.33 eV in Zn0.5Co0.5WO4, which is due to the formation of a Z-scheme for charge transfer and enhancement in photocatalytic efficiency. The experimental results suggested that ZnWO4, CoWO4, and Zn0.5Co0.5WO4 NPs achieved a photocatalytic efficiency of 97.89%, 98.10%, and 98.77% towards XO in 120 min of visible solar light irradiation. The kinetics of photodegradation was best explained by pseudo-first-order kinetics and the values of apparent rate const (kapp) also supported the enhanced photocatalytic efficiency of mixed metal Zn0.5Co0.5WO4 NPs towards XO degradation. [ABSTRACT FROM AUTHOR]

Aromatic amines are important chemical intermediates that hold an irreplaceable significance for synthesizing many chemical products. However, they may react with substances excreted from human bodies to generate blood poisoning, skin eczema, and dermatitis disease and even induce cancer-causing high risks to human health and the environment. Metal tungstates have been proven to be highly efficient materials for developing various toxic gases or chemical detection sensor systems. However, the major factors of the sensors, such as sensitivity, selectivity, stability, response, and recovery times, still need to be optimized for practical technological applications. In this work, Ni-doped ZnWO4 mixed metal tungstate nanocomposite material was synthesized by the hydrothermal method and explored as a sensor for the fluorometric determination of p-nitroaniline (p-NA). Transmission electron microscopy (TEM) was used for the elucidation of the optimized particle diameter. Scanning electron microscopy (SEM) was employed to observe the surface morphological changes in the material during the solid-state reactions. The vibration modes of as-prepared samples were analyzed using Fourier-transform infrared spectroscopy (FTIR). The chemical bonding and oxidation states of individual elements involved in material synthesis were observed using X-ray photoelectron spectroscopy (XPS). The PL activities of the metal tungstate nanoparticles were investigated for the sensing of p-nitroaniline (p-NA). The obtained results demonstrated that ZnNiWO4 was more effective in sensing p-NA than the other precursors were by using the quenching effect. The material showed remarkably high sensitivity towards p-NA in a concentration range of 25–1000 μM, and the limit of detection (LOD) value was found to be 1.93 × 10−8 M for ZnWO4, 2.17 × 10−8 M for NiWO4, and 2.98 × 10−8 M for ZnNiWO4, respectively. [ABSTRACT FROM AUTHOR]

The present study was aimed to remove direct violet-51, reactive green-5, reactive red, and acid red dyes by novel bentonite clay nanocomposites prepared using sodium metasilicate and potassium ferricyanide. The effect of temperature, pH, adsorbent amount, contact time, and initial concentration were studied to optimize the removal process. Various adsorption isotherms (Temkin, Freundlich isotherm, Langmuir isotherm, Harkin Jura, and Dubinin Radushkevich models) and kinetic models (pseudo-first order and pseudo-second order) were applied to adsorption data to find out the best fit model, i.e., Freundlich isotherm and pseudo-second order model. The prepared samples of bentonite nanocomposites were characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Bentonite treated with sodium metasilicate and potassium ferricyanide removed 96.6% of direct violet-51 dye, bentonite treated with sodium metasilicate removed 95%, bentonite treated with potassium ferricyanide removed 94%, and pure bentonite removed 80% of the dye from the solution. [ABSTRACT FROM AUTHOR]

The adsorption process combined with electrocoagulation is a highly effective technique for dye removal. Calcinized and non-calcinized composites based on bentonite and sodium zeolite were prepared for adsorptive removal of Foron EBL blue, Terasil brown 2RFL, Torque blue PG, and Orange P3R dyes. Factors affecting the adsorption process, such as contact time, initial dye concentration, and temperature, were also explored in this study. Equilibrium data of natural clay composites was explained by Freundlich, Langmuir, Dubinin Radushkevich isotherm, Harkin Jura, and Temkin isothermal models. Harkin Jura isotherm model best fitted on the adsorption mechanism compared to Langmuir and Temkin isotherm model. Morphology of clay-based adsorbents and functional group arrangement were investigated by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The calcinized nano-composite material exhibited better adsorption capacity than non-calcinized nano-composite and could be employed as a low-cost alternative for dye removal. [ABSTRACT FROM AUTHOR]

In this research work, a simple, efficient, and eco-friendly procedure for the biosorption of Cr(VI) ions was studied. A detailed comparative study was performed to check the adsorption efficiency of agrowaste (banana and potato peels)-based adsorbents. Firstly, mixed biosorbent was washed, dried and ground into powder, secondly, biosorbent was pyrolyzed into biochar and thirdly TiO2 nanocomposite (TiO2 NC) biosorbent was made by sonicating using prepared biochar and TiO2 NPs. Titanium dioxide nanoparticles (TiO2 NPs) were synthesized by a green method using Psidium guajava leaf extract. The synthesized adsorbents were characterized by SEM, EDX FT-IR, XRD and UV-visible analysis. The effect of four different factors, i.e., pH of the synthetic metallic solution, time, concentration and adsorbent dosage was studied. The optimum conditions were time (120 min), pH (3), concentration (10 ppm) and adsorbent dosage (1.0 g). The kinetic modeling showed that the adsorption of Cr(VI) ion follows a pseudo second-order mechanism and the Langmuir isotherm model was found to fit better for this study. Response surface methodology (RSM)-based optimized parameters provided optimal parameter sets that better represent the adsorption rate models. The uptake capacity of Cr(VI) from aqueous solution was found to be biomass (76.49 mg/L) ˂ biochar (86.51 mg/L) ˂ TiO2 NC (92.89 mg/L). It can be suggested that the produced TiO2 NC could possibly be an efficient biosorbent for the removal of Cr(IV). [ABSTRACT FROM AUTHOR]

The composite of ceria has been widely studied as an electrode material for supercapacitors applications due to its high energy density. Herein, we synthesize CeO2/NiO nanocomposite via a hydrothermal route and explore its different aspects using various characterization techniques. The crystal structure is investigated using X-ray diffraction, Fourier transform infrared, and Raman spectroscopy. The formation of nanoflakes which combine to form flower-like morphology is observed from scanning electron microscope images. Selected area scans confirm the presence of all elements in accordance with their stoichiometric amount and thus authenticate the elemental purity. Polycrystalline nature with crystallite size 8–10 nm having truncated octahedron shape is confirmed from tunneling electron microscope images. Using X-ray photoelectron spectroscopy the different oxidation states of Ce and Ni are observed which play the role of active sites in the electrochemical performance of this nanocomposite material. Cyclic Voltammetry(CV) measurements at different scan rates and Galvanic Charge Discharge (GCD) measurements at different current densities are performed to probe the electrochemical response which revealed the potential of CeO2/NiO nanocomposite as an electrode material for energy storage devices. [ABSTRACT FROM AUTHOR]

CeO2 and CeO2:Ag nanocomposite were synthesized using succinic acid as a fuel by a simple solution combustion method. This method neither demands surfactants nor long reaction time. Synthesized materials were identified through several analytical tools such as photoluminescence spectroscopy, Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, scanning electron microscopy and x-ray diffraction. The photocatalytic activity of prepared nanomaterials were investigated by the photodegradation of trypan blue dye by varying the initial dye concentration and catalyst dosage. The result revealed that CeO2:Ag nanocomposite have shown the better photocatalytic activity than the CeO2 nanoparticle at pH 5 under ultraviolet light irradiation. Furthermore, CeO2:Ag nanocomposite is immobilized and electrically wired via immobilization upon glassy carbon electrodes to permit the creation of CeO2:Ag nanocomposite electrochemical sensor, which has been successfully evaluated for sensing Hg(II) at nano-molar (nM) levels in model aqueous solutions across dissimilar pulse anodic striping voltammetry. [ABSTRACT FROM AUTHOR]

Herein, a facile green synthesis route was reported for the synthesis of Ag–ZnO nanocomposites using potato residue by simple and cost effective combustion route and investigated the photocatalytic degradation of methylene blue (MB) dye. In the preparation potato extract functioned as a biogenic reducing as well as stabilizing agent for the reduction of Ag + , thus eliminating the need for conventional reducing/stabilizing agents. Ag–ZnO nanocomposites with different Ag mass fractions ranging from 2 to 10% were characterized by using XRD, FT-IR, XPS, SEM, TEM, and UV–Vis spectroscopy. XRD analysis revealed that the as prepared Ag–ZnO nanocomposites possessed high crystallinity with hexagonal wurtzite structure. TEM and SEM images showed that the Ag–ZnO nanocomposites in size ranging from 15 to 25 nm have been obtained, and the particle size was found to increase with the increase in percentage of Ag. FTIR results confirmed the characteristics band of ZnO along with the Ag bands. XPS analysis revealed a pair of doublet with peaks corresponding to Ag and a singlet with peaks corresponding to ZnO. With the increase of concentration of Ag in ZnO, the intensity of NBE emission in the PL spectra was observed to be decrease, resulted to the high photocatalytic activity. Photocatalytic properties of Ag–ZnO nanocomposites evaluated against the MB dye under visible-light irradiation showed superior photodegradation of ~ 96% within 80 min for 2% Ag–ZnO nanocomposites. The apparent reaction rate constant for 2% Ag–ZnO nanocomposites was higher than that of other nanocomposites, which proved to be the best photocatalyst for the maximum degradation of MB. Furthermore, various functional parameters such as dosing, reaction medium, concentration variation were performed on it for better understanding. The enhancement in photocatalytic degradation might be due to the presence of Ag nanoparticles on the surface of ZnO by minimizing the recombination of photo induced charge carriers in the nanocomposites. [ABSTRACT FROM AUTHOR]

• First reports on hydrothermal synthesis of Ag/rGO@CTFE nanocomposite using Chamomile Tea Flowers Extract (CTFE). • Characterization of Ag/rGO@CTFE nanocomposite was done by Raman spectroscopy, XRD, FE-SEM with EDS, HR-TEM and FTIR analyses. • Hydrothermal synthesis of Ag/rGO@CTFE nanocomposite exhibited notable photo-catalytic action in carcinogenic organic dyes. The present study reports a green synthesized via eco-friendly hydrothermal treatment of silver-reduced graphene oxide (Ag/rGO) nanocomposite using chamomile tea flowers extract (CTFE). Initially, the synthesis of Ag/rGO@CTFE nanocomposite was confirmed by the formation of greyish black color. The synthesized Ag/rGO@CTFE nanocomposite was characterized by Raman spectroscopy, XRD, FE-SEM with EDS, HR-TEM and FTIR analyses. Spherical shape of the synthesized Ag/rGO@CTFE nanocomposite with varied sizes of 55-60 nm was observed by HE-TEM analysis. Face centered cubic crystalline structure of synthesized Ag/rGO@CTFE nanocomposite was confirmed by XRD analysis. In addition, Ag/rGO@CTFE nanocomposite exhibited 97% of Rhodamine B (Rh B) and 87% of Evans blue (EB) dye degradation activity under visible light irradiation. Ag/rGO@CTFE nanocomposite exhibited notable photo-catalytic activity in carcinogenic organic dyes. Hence, it's a first reports on hydrothermal treatment of Ag/rGO@CTFE nanocomposite using CTFE for photo-catalytic application. Image, graphical abstract [ABSTRACT FROM AUTHOR]

In this study, we report the fabrication of graphitic carbon nitride doped zinc oxide nanocomposites, g-C3N4/ZnO, (Zn-Us) by using different amount of urea. They were further characterized by X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Raman, UV-vis, Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM) techniques. The prepared nanocomposites were used as photocatalysts for the mineralization of the light sensitive dyes Methylene Blue (MB) and Rose Bengal (RB) under UV light irradiation, and corresponding photo-mechanism was proposed. Benefiting from these photocatalytic characteristics, urea derived g-C3N4/ZnO photocatalysts have been found to have excellent photodegradation activity against the MB and RB for 6 h and 4 h, respectively. Under the given experimental conditions, the degradation percentage of fabricated Zn-Us were shown ~90% for both model dyes. Compared to cationic MB dye, anionic RB dye is more actively degraded on the surface of prepared photocatalysts. The results obtained can be effectively used for future practical applications in wastewater treatment [ABSTRACT FROM AUTHOR]

Boroncarbonitride (BCN), a two-dimensional material has been successfully wrapped around a conductive polymer, polyaniline (PANI) through simple insitu polymerization method. X-ray diffraction (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), Tunneling Electron Microscopy (TEM) and Fourier Transform Infrared (FTIR) studies confirm the functionalization of PANI with BCN. PANI, BCN, and PANI/BCN nanocomposite materials have been evaluated and compared their electrochemical performance for supercapacitors in a system containing three electrodes. Using cyclic voltammetric (CV) technique, the specific capacitance value of PANI has been greatly improved upon functionalization of BCN and achieved 951 Fg-1, which is very high on comparing the specific capacitance value of PANI (376 Fg-1) and BCN (487 Fg-1) at a scan rate of 2 mVs−1. The same trend of improved specific capacitance has also been observed in chronopotentiometric (CP) technique. To further evaluate the electrochemical property of the synthesized materials, two-electrode system asymmetric supercapacitor device fabrication has been carried out using PANI/BCN nanocomposite as anode material and achieved the specific capacitance of 67.1 Fg-1 at a scan rate 5 mVS−1 for PANI/BCN nanocomposite. The obtained electrochemical performance of all the three materials synthesized, could serve as an alternative material for asymmetric supercapacitor devices. Image 1 • Polyaniline functionalized with boroncarbonitride by insitu polymerization. • Homogenous functionalization resulted in wrapping of BCN around PANI. • Enhanced electrochemical performance of PANI/BCN nanocomposite compared to pure PANI and BCN. • Fabrication of PANI/BCN composite for asymmetric supercapacitor device. [ABSTRACT FROM AUTHOR]