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A pure MgO and MgO doped with 2, 4, 6, and 8 mol% of NiOnanoparticles (NPs)were prepared using the solution combustion technique.Several spectral techniques were used to characterize the synthesizedNPs.The XRD analysis revealed theaverage particle size of theMgO-infused NiO nanomaterialwas ranging between 16.28 and 71.26 nm.A distinct plate-like or slice-like quality to the morphology was observed during the SEM analysis. The average energy gap (Eg) value of NiO doped MgONPs(Ni:MgONPs)was found to be 4.29 eV.The preparedNi:MgONPsexhibited good electrochemical characteristics. These nanoparticles were successfully used for the detection of diclofenac molecule using the modified graphite electrodes with 0.1 N HCl as an electrolyte.The results shows an oxidation peak at 0.19 V before diclofenac was added, later it is migrated significantly towards the positive potential (0.07 V) after diclofenac was added. The pure MgO and MgO doped with 2, 4, 6, and 8 mol% of NiOwere used for further studies of photodecolorization of Drimaren blue dye under UV/sunlight irradiation.The reduction in the peak intensity of Drimaren Blue dye was observed. MgO exhibited an enhanced photocatalytic activity of 68.7 % and MgO:NiO exhibited 81.9 %.According to these studies, the 6 mol% NiO doped MgO is a viable choice for the wastewater treatment and electrochemical detection of diclofenac.

The electrical properties of bismuth magnesium tantalate pyrochlore, Bi3.30Mg1.88Ta2.82O13.88 (BMT) were investigated by both inductor-capacitor-resistor (LCR) and impedance spectroscopy techniques covering a broad temperature range of 10–1073 K and a frequency range of 5 Hz - 1 MHz. At below ∼180 K, BMT pyrochlore exhibited interesting relaxor behaviour that showed high dispersion characteristics in its frequency-temperature dependent dielectric constants, ε′ and dielectric losses, tan δ, respectively. The maximum ε′max of ∼77 was obtained at the temperature maximum, Tm of 154 K. The frequency-independent ε′ data above 154 K at a fixed frequency of 1 MHz can be well fitted with the Curie-Weiss law and the relaxation features of Bi3.30Mg1.88Ta2.82O13.88 obeyed the Vogel-Fulcher equation. The dielectric properties of Bi3.30Mg1.88Ta2.82O13.88 relaxor in the low temperature range of 20–320 K could be satisfactorily modeled with different equivalent circuits. In this perspective, a master circuit consisting of a parallel R-C-CPE element in series with a capacitor was required to accurately fit the low temperature data.

Scientific interest in antimicrobial pollutants, such as ciprofloxacin, has increased. Due to spread of antibiotic-resistant bacteria, resistance genes, and their dissemination to the environment. Therefore, their remediation is necessary to ensure ecological sustainability. The current study aimed to optimise the removal of ciprofloxacin from synthetic water using jamun seed (JS) (Syzygium cumini) biochar using a response surface methodology (RSM). Result indicates ciprofloxacin elimination efficiency ranged between 32.46 and 94.95%, indicating the material can be improved and used for remediation of organics. The residual standard error of 4.4% were found for the predicted model, implying that the model is credible and can be used to predict future experimental findings. The R-squarred value for the improved Langmuir model's R2 is 0.9681 which is inclose agreement with the Freundlich isotherm, R2 0.9757. Therefore, JS biochar could be utilized for the remediation of ciprofloxacin from contaminated water and wastewater for ecological safety and sustainability.

Previous studies have shown that co-doping of BST resulted in enhanced dielectric properties of BST. Meanwhile, no work was reported about effect of Mo, Se on the dielectric properties of Barium strontium titanate (BST). Hence, this report was expected to contribute on the ways of enhancing the dielectric activity of BST through doping. The purpose of the research was to investigate the microstructural, morphological as well as the dielectric properties of BST and Mo, Se co-doped BST following their slow injection sol–gel synthesis and calcined at 800 °C. The effective synthesis of cubic Ba0.6(Sr0.4-xSex)(MoyTi1-y)O3 nanopowder has been confirmed using FT-IR, Raman spectroscopy, EDS, and XRD techniques where the presence of every element and the empirical formula matched with the predicted ones. The average crystallite size of BST increased from 23.97 nm to 26.18 nm after doping. Likewise, the average grain size elevated from 40.13 nm to 53.27 nm accompanied by the elevation of the number of agglomerated crystallites in a grain per SEM particle (1.98 to 3.55). The average particle size of Mo and Se co-doped BST was found as 26.63 nm. The lowering of pore size as well as pore volume of BST was also observed after doping. All these properties led to the elevation of dielectric constant (from 248.8 to 953.00) and lowering of the dielectric loss (from 0.1620 to 0.0928). Therefore, the Mo, Se co-doped BST possessed such varied properties from BST which makes it to be effectively utilized in capacitive applications such as supercapacitors.

La10Si6O27: Tb3+ (1–9 mol%) materials were synthesized by the combustion method and characterized by PXRD, PL, CV, EIS and UV–Vis spectroscopy to explore its photoluminescent, electrochemical and photocatalytic properties. These materials exhibited crystalline and single phases even after doping Tb3+ ions into the lattice of La10Si6O27. PL analysis confirms a tunable and maximum emission for optimized concentration. Electrochemical analysis shows La10Si6O27:Tb3+ (9 mol%) electrode as a paracetamol and penegra sensing material. The average specific capacitance of this electrode at 10 mVs−1 was found to be 262 Fg−1. A Photocatalysis study was performed using La10Si6O27:Tb3+ (5 mol%) material as a photocatalyst for the degradation of direct green dyes. Therefore, La10Si6O27:Tb3+ can be used as a multifunctional material for photoluminescence, photocatalysis, and electrochemical sensing applications.

Montelukast Sodium (MK) is a leukotriene receptor antagonist, an oral drug generally prescribed to control chronic asthma symptoms. This research aims to provide the transdermal delivery of this drug in a controlled release profile as a better mode of drug delivery, specifically for the pediatric and elderly population. Transdermal delivery of the drug not only improves the drug's bioavailability but also maintains the concentration of the drug in the plasma without increasing the frequency of the drug dosage. Transdermal film formulations were developed using sodium alginate (SA) and lignosulphonic acid (LS) as the matrix and PEG-400 or Glycerine (Gly) as the plasticizers. Various physiochemical characteristic evaluations of the formulated films were conducted, revealing that the formulation with Glycerine as the plasticizer had a smooth surface and was flexible. It was observed that this formulation had the highest moisture uptake capacity and the lowest moisture loss capacity when compared with the other two formulations. It was also observed that the barium chloride cross-linked formulation had a higher swelling index when compared with calcium chloride cross-linked films. The surface pH of all the formulations was monitored to be around 7.5. In the in vitro release studies, the cross-linked films showed a controlled release over 36 h compared with the non-cross-linked films. Based on the observations and results, the cross-linked film formulation showed a better-controlled release of the drug and could potentially increase its bioavailability. TGA analysis of the polymeric mixture demonstrated the thermal stability of the SA blends, which enhanced the flexibility of the SALS blend with Glycerine. XRD of samples confirmed the amorphous nature of SALS blends with Gly, which influences the flexibility of the blend. The blends are further investigated for morphology using SEM to test their compatibility with the drug.

In this paper, we report on the synthesis of strontium oxide nanoparticles (SONPs) using a novel probe sonication method. Powder X-ray diffraction (PXRD) was used to characterize the physicochemical properties of the prepared materials, which confirmed that the average SrO crystallite size was 43 ​nm. The Kubelka-Monk function of diffuse reflectance spectroscopy (DRS) was used to confirm the average energy gap of SONPs (4.06 ​eV). SONPs have been successfully used in conjunction with inventive photocatalysts to remove dyes such as Methylene Blue (MB) and Acid Green (AG). MBand AG dyes were used as standard dyes to investigate the photocatalytic properties of NPs when exposed to UV light and sunlight.These nanometal oxides photodegrade methylene blue (87.70%) and acid green (71.20%) dyes with remarkable efficiency when exposed to UV light. These nanometal oxides demonstrated superior sensitivity when paracetamol was used as an analyte in cyclic voltammetry tests at various scan speeds (10 ​mV/s to 50 ​mV/s). As a result, SONPs may be useful in photocatalytic activity and electrochemical sensor applications.

Hybrid nanostructured materials currently offer a potential approach for a variety of applications due to improvements in their physio-chemical characteristics. Techniques for XRD, TEM-HRTEM, SAED, and UV-DRS were used to characterize the Cu2ZnAl2O4 (CZA) material. Without any secondary phases and with an average crystallite size of 40 ​nm, X-ray diffraction pattern examination demonstrates the increased crystalline structure. A highly crystalline, polydisperse CZA nanostructure was visible using TEM-HRTEM and SAED. The CZA nanostructure's light-absorbing behavior is presented by UV-DRS analysis, which found that the predicted bandgap energy was 5.0 ​eV. In this article, we describe an easy chemical synthesis of a hybrid CZA nanostructure that works well as a catalyst to break down the acid red 88 (AR-88) dye under UV, sunlight, and low light conditions. Additionally, it was studied to determine how to modify the working electrode's surface to enable the detection of lead and tin metal ions. With 93.1% of degradation and comparison work on decolorizing AR-88 dye in the presence of both sunlight and darkness, CZA nanostructure was looked at as a potential catalyst for the decolorization of AR-88 dye. By using graphite electrode paste and cyclic voltammetry to analyze the synthesized sample in 1 ​N KCl, it was discovered that it had outstanding redox reaction and lead and tin detection capabilities.

Nanocrystalline titanium oxide nanoparticles (TiO2 NPs) were synthesized by using a low-cost sonochemical method. TiO2 NPs exhibited anatase phase and an average crystallite size of 40.64 ​nm, according to a powder X-ray diffraction (PXRD) investigation. SEM and TEM images revealed spherical shape, with asymmetric geometries for TiO2 NPs. The micrographs thoroughly corroborated the plate-like structure for the NPs. In order to confirm the average energy gap of TiO2 NPs, diffused reflectance spectroscopy (DRS) via Kubelka-Monk function was applied (3.66 ​eV). Navy blue dye was used to study the photocatalytic properties of NPs and discovered to be triggered at 590.9 ​nm. The photodegradation rate of NB dye decolorized up to 74.04% after 120 ​min of UV light exposure. The first order kinetics was indicated by a linear relationship between log C/Co and k. The demonstrated rates of photodecoloration for NB under UV light in the presence of scavengers AgNO3, ethanol, and ethylenediamine tetraacetic acid (EDTA), were found to be 65.50%, 61.46%, and 57.33%, respectively. Using the carbon paste electrodes and cyclic voltammetry (CV) in 0.1 ​N HCl solution, the electrochemical characteristics of the obtained sample were studied. The carboxymethyl cellulose sensor made from TiO2 NPs demonstrated a remarkable sensitivity of 0.08 A. The results showed a high recovery for lead with low% of RSD values. The TiO2 electrode is a promising electrode material for sensing applications due to its outstanding electrochemical performance.

The present work deals with the synthesis of cerium oxide (CeO2) nanoparticles (CONPs) using sodium hydroxide and cerium nitrate as precursors via Sonochemical route. As synthesized, cerium oxide nano powders were calcined at 1000 °C to 1100 °C for 2 hrs. The obtained CONPs were characterised by using the advanced analytical methods. XRD (X-ray diffraction) analysis confirmed the pristine cubic fluorite structure for CeO2 NPs. The FTIR spectrum shows a strong broad band around 800 to 900 cm−1, for Ce-O stretching vibration to confirm the formation of pure CeO2. The particle size of CONPs was found to vary between 35 and 38 nm. Under UV light irradiation of the commercial dye methylene blue, these nano metal oxides demonstrated significant efficiency in photo degradation. A specific capacitance value of 59.78 Fg−1 was obtained from the cyclic voltammograms of the CeO2 electrode in 0.1N HCl solution with a scan rate of 10 to 50 mV/s. These electrodes have proved to be very sensitive towards the detection paracetamol. These findings revealed that CeO2 is an effective photocatalyst and a suitable electrode material for detecting paracetamol with high electrode reversibility.

In order to explore an alternative photocatalyst for environmental remediation, we report the sol-gel process for the synthesis of strontium titanate (SrTiO3) nanoparticles (STNPs). The as-synthesized STNPs were found to poses cubic perovskite-type crystal structure with an average crystallite size of 22 nm were well-characterized by X-ray diffraction (XRD). The agglomerated and cubic like morphologies were identified by using scanning electron microscopy (SEM). The elemental analysis by energy dispersive X-Ray spectroscopy (EDAX) confirmed the composition of STNPs. The synthesized nanoparticles were further characterized by Fourier transform infrared (FTIR) analysis. STNPs displayed good photocatalytic degradation activity for malachite green (MG) and rhodamine blue (Rh–B) dye pollutants under UV light irradiation in the time duration of 120 min. Furthermore, cyclic voltammetric studies revealed that the STNP electrode, because of its increased surface area, produced maximal specific capacitance of 208.47 Fg−1 at 1 mA/cm2 with a high cycle stability of 1500 cycles. The superior supercapacitance behaviour of SrTiO3 electrode materials strengthens its stance to be developed as a highly promising material for energy related applications. In addition, STNPs can serve as better materials for the environmental remediation of pollutant dyes.

The word ‘Nano’ received great attention of world, due to their fabulous and novel applications in numerous fields. Cadmium sulphide nanoparticles (CdS NPs) are unique in their properties due the size and shape, and are popular in the area of biosensor, bio-imaging, nano-medicine, molecular pathology, antimicrobial activities, photovoltaic cells, semiconductor, and drug delivery, etc. Due to its fascinating applications, it was synthesized using several methods and explored for its all possible applications. The most affordable, efficient, friendly and biocompatible way of creation of CdS NPs is biogenic synthesis using microorganisms such as bacteria, fungus, algae, enzymes, proteins and parts of plants. In biogenic synthesis of CdS, cadmium undergoes bio-reduction by the variety of natural products present in microorganism as well as in plants. In present review, inclusive study was piloted on the nano-synthesis, characterization and various applications of CdS NPs made using different plant sources and microorganism.

Lanthanum oxide (La2O3) nanoparticles (NPs) were prepared by the facile green combustion method using the leaf powders of Centella asiatica and Tridax plants (C-La2O3 and T-La2O3 NPs). Various analytical and electrochemical techniques were employed to understand the morphology, crystallinity, and band gap of La2O3 NPs. X-ray diffraction (XRD) studies revealed that the NPs exists in a hexagonal crystal structure with a crystallite size of 20 nm. The morphological studies (SEM and TEM) revealed La2O3 clusters with porous structures. UV-DRS (diffuse reflectance) spectra was used to arrive at the band gap of 5.44 eV and 5.61 eV for C-La2O3 and T-La2O3 NPs. The thermogravimetric studies showed a 2-step decomposition process involving La(OH)3. Electrochemical and photocatalytic studies were conducted to explore the efficiency of C-La2O3 and T-La2O3 NPs. The better photocatalytic degradation was observed for T-La2O3 NPs with 60% efficiency. In addition, La2O3 NPs also exhibited good antimicrobial activities.

The vast improvements made by the human species in household, scientific, and commercial spheres come at the expense of environmental pollution. Due to its direct connection to all living forms, aquatic pollution is a severe issue. Tons of home and industrial contaminants enter aquatic systems every year; their proficient removal and degradation is crucial for a sustainable future. A new and promising technology for the efficient removal of aqueous contaminants is photodegradation. Carbon dots (CQDs) have recently emerged as one of the most effective materials that may be used to generate a variety of chemical processes that are driven by the sun. Outstanding physicochemical characteristics, including light-harvesting, photosensitizers, and redox characteristics, are present in CQDs. A simple and affordable photocatalyst for the oxidation of aqueous pollutants is CQDs. The most recent developments in the field of photodegradation of aquatic contaminants with the assistance of carbon quantum dots (CQDs) alone and with dopant are summarized in this mini-review.

The molybdenum oxide nanoparticles (MoO3 NPs) have been successfully synthesized via green combustion method using Centella asiatica plant powder. The powder x-ray diffraction (PXRD), Fourier transform infrared spectroscopic (FTIR), scanning electron microscopic (SEM) and diffuse reflectance spectroscopic (DRS) techniques were used to characterize the MoO3 nanoparticles. The PXRD patterns of the sample revealed pure hexagonal phase. The Scherrer's method was employed to find the crystallite size of the synthesized material and the result obtained was confirmed by the TEM analysis. The optical energy band gap value (Eg) of the sample was calculated using the Tauc relation, and it was found to be around 3.41 ​eV. The photocatalytic degradation of MoO3 NPs on Direct Green (DG) and Navy Blue (NB) dye was evaluated under UV light irradiation. The electrochemical study of prepared electrode with graphite powder in 0.1 ​M KOH electrolyte solution displayed superior redox potential output as intended by cyclic voltammetric and amperometric studies, where the material was employed for its sensing abilities such as a highly toxic metal like lead.

The rare earth (RE = Eu, Sm, Dy, and Tb) ions doped La10Si6O27 nanophosphor was synthesized by a simple solution combustion method. The prepared La10Si6O27:RE3+ nanophosphors (LNPs) were subjected to diverse technical tools for exploring their structural, optical, morphological, and electrochemical features. The structural analysis using powder X-ray diffraction (PXRD) patterns revealed the hexagonal oxy apatite phase for LNPs with a crystallite size in the range of 25–50 nm, and the equivalent was affirmed by image analysis via transmission electron microscopy (TEM). Utilizing DRS data, the bandgap energy (Eg) values were recorded for LNPs. Cyclic voltametric (CV), electrochemical impedance spectroscopy (EIS), and sensor studies were performed using a modified carbon paste electrode of LNPs. The modified LNP electrodes were found to be highly effective in sensing paracetamol in acidic medium with a quick response time of 3 secs for sensing the drugs at 1 mM concentration. All the RE ions Eu3+, Sm3+, Dy3+, and Tb3+ (5 mol%)-doped LNPs exhibited the most promising electrochemical sensing characteristics.

A moderate pyrochlore solid solution range of 0.00 ≤ x ≤ 0.64 was observed in the Bi3.36Fe2.08+xSb2.56-xO14.56-x (BFS) system prepared by solid-state reaction at 925 °C for 2 days. The overall charge compensation required a one-to-one cationic replacement and oxygen vacancies, i.e. Sb5+ ↔Fe3+ - O2–. BFS cubic pyrochlores showed their refined lattice parameters varying linearly in the range of 10.4284 (8)-10.4513(8), thus obeying the Vegard's rule. The measured crystallite sizes by both Scherrer and Williamson-Hall methods were found to be in the range of 46–67 nm; whilst, the larger grain sizes in the range of 0.2–2.9 μm were calculated using scanning electron microscopy (SEM) analysis. The AC impedance analysis also verified a few electrical responses of BFS pyrochlores: (i) BFS pyrochlores had moderate dielectric constants in the range of 24–35 and dielectric losses in the order of 10−1 at room temperature and 1 MHz, (ii) BFS pyrochlores were not electrically homogeneous with bulk capacitances in the order of 10−12 Fcm−1, (iii) a non-Debye type and temperature-dependent relaxation process were discernible and (iv) the movement of charge carrier were either in the long-range or short-range migration subjected to time availability. In addition, BFS pyrochlore thin films had a good capacitive behaviour and electrochemical reversibility, according to the cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) analyses. All these excellent properties rendered BFS pyrochlores to be a suitable material for Class 1 ceramic capacitors.

The present study confirms the application of phytochemicals of Lemon rind (LR) towards the synthesis of activated carbon using a low temperature carbonization method. The structural, morphological, and electrochemical properties of the prepared carbonized flakes epoxy (CFE) electrode has been analyzed using various characterization techniques. The electrochemical double layer capacitance (EDLC) behavior of the LR-activated carbon has been evaluated. The synthesized LR-activated carbon material exhibited flake like structure along with hydroxyl groups as confirmed by studies by scanning electron microscope (SEM), X-ray diffractometer (XRD), and Fourier transform infrared (FTIR) spectroscope. In addition, the band gap energy (Eg) has been estimated using diffused reflectance spectroscopy (DRS-UV-Vis) and found to be 2.06 eV. The electrochemical property of CFE-electrode was studied utilizing cyclic voltammetric (CV) and electrochemical impedance spectroscopic (EIS) techniques. The galvanostatic charge–discharge tests for this prepared carbon flake electrode demonstrated excellent capacitance performance, making it favorable for the fabrication of supercapacitors. These progressive results could be considered for the enlargement of novel assets to scale for power-storage utility using low-cost carbon materials in various energy storage applications as well.

Zinc oxide nanoparticles (ZnO NPs) have proven record of exhibiting multifunctional properties and thus utilized for diversified applications. ZnO NPs were successfully synthesized by chemical and green routes. The Syzygium cumini plant leaf extract was used to synthesize green ZnO NPs. The chemical and green ZnO NPs were characterized by using advanced technical tools to explore their bonding, structural and morphological features. The PXRD (Powder X-Ray Diffraction) patterns confirmed the hexagonal phase of ZnO with wurtzite structure. The scanning and transmission electron microscopic (SEM and TEM) analysis revealed rectangular flake like structures for chemical ZnO whereas spherical structures were found for green ZnO NPs. Maximum antibacterial activity was observed against Pseudomonas aeruginosa bacterial strain with zone of inhibition of 14.5 mm followed by 5 mm for Klebsiellaoxytoca and 4 mm for Escherichia coli for green ZnO NPs. The percentage of inhibition was found to be 85, 29 and 50 for Pseudomonas aeruginosa, Klebsiellaoxytoca and Escherichia coli bacterial strains. The percentage of inhibition of mycelial growth observed during antifungal testing was varied from 5% to 70%. The photocatalytic efficiency of 98 % for Acid Red 88 dye degradation was recorded for ZnO NPs. Green ZnO NPs exhibited better antibacterial and antifungal activities, in addition to superior photocatalytic behaviour.

We report the synthesis of medicinal plant, Vernonia amygdalina Del. mediated green copper oxide nanoparticles (VeA-CuO NPs). The presence of two absorbance maxima, λmax 1 and λmax 2 at 436 nm and 452 nm, respectively confirms a mixture of biomolecules surface amalgamated CuO NPs with different morphological features. The FT-IR spectra of the plant leaf extract and VeA-CuO confirmed the efficient role of biomolecules as capping and stabilising agents. The XRD patterns of NPs approved high crystallinity of CuO. The purity of the NPs was corroborated by SEM-EDAX analysis. The average particle size of the NPs was found to be 19.68 nm. In addition, the combined TEM, HRTEM and SAED analysis substantiated the presence of CuO with a d-spacing value of 0.2854 nm, which conformed to CuO (111). The antibacterial assay revealed that VeA-CuO NPs were synergistic in their influence versus bacterial strains, S. aureus, E. coli, P. aeruginosa, and E. aerogenes. The uppermost zone of inhibition of 15 mm was observed for E. aerogenes. The bioactive compounds capped around the CuO NPs served the effective role in disrupting the cell wall of bacterial strains. The degradation efficiencies for Indigo carmine (IC) and Malachite green (MG) dyes by NPs were found to be 95% and 91%, respectively. The lowest degradation half-life was recorded to be 16.55 min for MG dye. In addition, the better electrode stability revealed by CV and EIS studies, confirms the multi-functional nature of VeA-CuO NPs, these CuO NPs exhibited multifunctional applications.

Graphene has been a prominent choice as a base material for supporting varieties of inorganic and organic materials in scientific research and innovation due to its superior physico-chemical properties. Electrochemical sensors have been prepared by the use of a variety of nanoparticles and based on graphene which effectively supported on the surface of glassy carbon electrode through different methods. Graphene supported sensors have been utilized to detect and determine different electroactive species in samples. Many characterization techniques such as Powder X-ray diffraction (XRD), Energy dispersion spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), UV–Vis spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, High-resolution transmission electron microscopy (HRTEM), Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) have been successfully applied to explore the properties of graphene supported nanomaterials. Applications of the sensors have been assessed using signals from electrochemical measurements such as: cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Differential pulse voltammetry (DPV). The results obtained from these measurements have data of wide liner range with small detection limit. Most of the results also clarified that the sensors were used to detect respective species with high sensitivity, and good stability. The electrochemical sensing of H2O2, hydrazine, dopamine, sunset yellow, flavonoids, caffeine, glucose, L-lactic acid, chrysophanol, etc., by graphene and graphene oxide-based nanomaterials has also been discussed in detail. This fact proved that there is a bright future for the development of portable sensors used in a variety of applications. The present review is focussed on exploring the synthetic methods, characterization and sensor applications of various graphene supported nanomaterials.

The zinc oxide nanoparticles (T-ZnO NPs) were synthesized successfully by the application of leaf, stem and callus extracts of Tabernaemontana heyneana Wall. via the green combustion method. The structural, bonding and morphological features of T. heyneana mediated ZnO NPs (T-ZnO NPs) were explored using XRD (X-ray powder diffraction), UV–Vis (Ultra-violet visible spectroscopy), FESEM-EDS (Field Emission-SEM and energy-dispersive X-ray spectra), DLS (Dynamic light scattering) and FTIR (Fourier transform infrared) techniques. UV–Vis spectra revealed the presence of a band in the region between 370 and 376 nm approving the presence of T-ZnO NPs. XRD, FESEM-EDS, TEM and DLS analysis confirmed the formation of nanosized, spherical shaped, highly stable and pure crystalline wurtzite T-ZnO NPs. FTIR spectra revealed the presence of most probable phytochemicals from plant extracts involved in the processes of reduction and stabilization of T-ZnO NPs. The T-ZnO NPs could effectively inhibit the activity of DPPH (1, 1-Diphenyl-2-picrylhydrazyl) radical (IC50 value between 467.7 and 752.3 µg/ml) exhibiting potent radical scavenging activity. The T-ZnO NPs exhibited strong anti-inflammatory (membrane stabilization) activity. The antidiabetic potential of T-ZnO NPs was assessed and found to exhibit excellent α-glucosidase (IC 50 at 16.3 µg/ml) and α-amylase (IC 50 at 42.3 µg/ml) activity. The cytotoxic effect of T-ZnO NPs was investigated against A549 cell line (human lung cancer) by MTT assay which showed dose dependent response. IC50 values were found to be in the range of 89.47–185.8 µg/ml demonstrating their higher cytotoxic efficacy. AO/EB staining indicated the presence of early apoptotic cells. The percentage degradation of carcinogenic methylene blue dye was studied and an outstanding catalytic activity of 87–100% was recorded by ZnO-NPs within 160 min. Hence, T-ZnO NPs proved to be better candidates for futuristic biomedical and industrial applications.

In this study, calcium magnesium aluminate (Ca3MgAl10O17) nanomaterials (CMA NMs) have been synthesized via a simple and cost-effective chemical combustion method using urea as a fuel for the first time. The orthorhombic crystal structure of CMA NMs was confirmed during X-ray diffraction analysis. The lattice grain size of CMA was found in the range of 20 to 25 nm. Kubelka–Munk function was utilized to study diffuse reflectance spectra and the band gap of the nanoparticles was determined to be 5.42 eV. HRTEM-SAED analysis revealed that the CMA NMs were nearly spherical in shape with interplanar spacing value of 0.19 nm. Acid orange-88 (AO-88) dye was used as a model dye to study the photocatalytic properties of the NMs under ultraviolet light irradiation. The degradation study on CMA NMs conformed superior AO-88 dye degradation with 92.25% efficiency proving these NMs to be excellent photocatalysts. The EIS measurements revealed the low charge transfer resistance (Rct) and high capacitance (C) values of 35.36 Ω and 2.815 × 10-3 F respectively, for the prepared CMA electrode. For sensor-based applications, dextrose and metal ions like arsenic, lead, mercury and tin were chosen as analytes. The modified carbon paste electrode of CMA NMs exhibited decent charge transfer properties with an efficient dextrose sensing ability in KCl electrolyte and metal sensing ability in alkaline medium. These results corroborated that the CMA NMs can be a promising electrode material for sensing dextrose and few selected metals with high electrode reversibility. The synthesized CMA NMs are expected to offer significant futuristic opportunities towards multifunctional applications for environmental remediation.

For the first time, Tb3+ ions were successfully doped into La10Si6O27 by using low temperature initiate solution combustion method. The resulting Tb3+ doped lanthanum nanophosphors (LNPs) were characterized by PXRD, FTIR, TEM and UV-DRS techniques. The PXRD patterns of calcined sample show a pure hexagonal oxy apatite phase. The crystallite size was found to be within a range of 25–40 nm and it is matched with TEM results. The energy band gap (Eg) was found to vary from 5.64 eV to 5.77 eV. The photocatalytic degradation of Disperse Orange (DO) and Fast Blue (FB) dyes by La10Si6O27:Tb3+ was tested under the irradiation of UV light. La10Si6O27: Tb3+ NPs showed enhanced degradation for Disperse orange and Fast blue dyes under UV light. La10Si6O27:Tb3+ (5 mol %) electrode exhibited reversible electrode reaction with low charge transfer resistance and high capacitance value. All the above findings confirm that the synthesized LNPs is a potential candidate for waste water treatment and sensor applications.

The current work involves the synthesis of a series of Eu3+ (1–11 mol%) doped La10Si6O27 nanophosphors (ELNPs) by solution combustion method using oxalyl dihydrozil (ODH) as a fuel for the first time. The PXRD studies revealed the average crystallite size in the range 15–35 nm for ELNPs. DRS studies revealed the energy gap of Eu3+ (1–11 mol %) doped La10Si6O27 is ~5.4 eV. The Photoluminescence (PL) studies of the ELNPs showed all the characteristic emission of Eu3+ cations and optimal emission intensity was observed for 5 mol % concentration of Eu3+ ions. The excitation maxima detected at 360 nm, 379 nm, 391 nm, 400 nm, 413 nm and 462 nm were conformed to transitions from 7F0→5G3, 5G4, 5L6, 5D4, 5D3 and 5D2 states of Eu3+ ions respectively. The observed intensities of PL transitions clearly indicated great potentiality for the fabrication of blue/near UV-LED excited phosphor for WLEDs. The calculated CIE chromaticity coordinates confirm the red emission and were depicted in the CIE diagram. The paracetamol and penegra materials were effectively sensed by the prepared carbon paste electrode of Eu3+ (3 mol %) doped La10Si6O27 as revealed by cyclic voltammetric and EIS studies. All the above results show that the synthesized ELNPs can be a potential candidate for display and electrochemical sensor applications.

The preparation, characterization, and application of Nickel oxide (NiO)–Copper oxide (CuO)–Zinc oxide (ZnO) transition nanometal oxides have significantly enhanced their tunable properties for superior multifunctional performances compared with well-known metal oxides. NiO–CuO–ZnO nano transition metal oxides were synthesized by a simple eco-friendly solution combustion method. X-ray diffraction studies revealed distinct phases such as monoclinic, cubic, and hexagonal wurtzite for CuO, NiO, and ZnO, respectively, with NiO having the highest composition. The particle sizes were found to be in the range between 25 and 60 nm, as determined by powder X-ray diffraction. The energy bandgap values were found to be 1.63, 3.4, and 4.2 eV for CuO, ZnO, and NiO, respectively. All metal oxides exhibited a moderate degradation efficiency for AR88 dye. The results of ultraviolet–visible absorption spectra helped identify the bandgap of metal oxides and a suitable wavelength for photocatalytic irradiation. Finally, we concluded that the electrochemical studies revealed that the synthesized materials are well suitable for sensor applications.