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A novel, highly efficient, reusable heterostructured nanocomposite photocatalyst and antibacterial agent was prepared successfully by combustion method. The structural and crystallinity of synthesized nanocomposites were well characterized by Powder X-ray diffraction (P-XRD) which confirms the purity and phase formation by diffraction peaks related to CuO, Cu 2 O, metallic Cu of nanocomposites. The proximity of Fe directly affects the crystallinity of Cu 2 O/CuO/Cu (CCC) and changes the morphology with observable voids and pores in Scanning Electron Microscopy (SEM). In addition, X-Ray Photoelectron Spectroscopy (XPS) results indicated the existence of doped Fe as Fe3+ and Fe2+ ions within the CCC nanocomposite lattice. The UV–Visible absorption spectroscopy illustrates a decrease in the band gap energy for the nanocomposites CCC (1.9 eV) and CCC-Fe (1.7 eV) which proves the dopant Fe hinders the recombination of e-–h+ pairs by trapping electrons and holes, causing an enhancement in this degradation process. This depicts the ability of Fe-doped CCC as a better photocatalyst under Sunlight irradiation than CCC. This was confirmed by the obtained results of photocatalytic performance of Fe doped CCC (5 mol%) on Methylene Blue (MB) and Rhodamine B (RhB) dyes. The degradation was found to be 93% and 81% respectively under irradiation of Sunlight for 60 min, whereas for CCC, the obtained result was 65% (MB) and 60% (RhB) under same condition. The CCC-Fe nanocomposite also shows considerable specific capacitance with 84.55 F/g from cyclic voltamogram and 83 F/g from charge discharge studies with durability of 2000 cycles ascertains the supercapacitor nature. Further, the remarkable antibacterial activities of Fe-doped CCC nanocomposites against E. coli and S. Aureus (100 μg/mL) were discussed. The excellent results of Fe-doped CCC nanocomposite showed a prominent multifunctionality in suppressing organic pollutants and bacteria in the environment. [ABSTRACT FROM AUTHOR]

This research deals with the facile combustion synthesis of manganese ferrite (MFO) nanoparticle with different cerium concentration and their potential application as an efficient photocatalyst and chemical sensor. The concentration of introduced cerium affects the size, structure, compositional, morphological, optical, photoluminescence and magnetic properties of the ferrite nanoparticle. The X-ray diffraction pattern affirmed the arrangement of cubic spinel structure with the formation of secondary phase CeO 2 as the cerium concentration exceed 3 mol%. SEM micrographs revealed irregular morphology with more number of pores and voids. HRTEM along with SAED pattern revealed the crystalline cubic nature. The optical band gap deduced from UV–Vis-DRS spectra was observed to be in the range 2.3–2.8 eV. PL studies indicated a significant minimization in combination of electrons & holes in MnFe 2 O 4 on addition of Ce dopant. VSM investigation demonstrated the soft magnetic nature of the prepared sample with moderate magnetization value. An excellent photocatalytic performance of Cerium doped MFO (3 mol%) towards MB and AR dye degradation was found to be 1.5 and 1.67 times more compared to host matrix under Sunlight irradiation that correlated to reduced band gap, Ce dopant and efficient separation of charge carriers. Cerium doped MFO (3 mol%) have high specific capacitance value of 471.7 and 1546.8 Fg-1 for NaNO 3 and HCl electrolytes respectively, indicating the pseudo capacitance nature due to which it can be used as a supercapacitor. The synthesized nanoparticles can sense d -Glucose and Paracetamol even at a lower concentration varying from 1 to 10 mM. The synthesized Ce-doped MnFe 2 O 4 nanomaterials have great potential to be used in the future production of promising active photocatalysts and sensitive chemical sensors for the identification and degradation of toxic industrial dyes for improved safety in the fields of environment and health care. [ABSTRACT FROM AUTHOR]

Photocatalytic activity of (CuO-Cu 2 O)Cu/ZnO hetero-junction nanocomposites along with their luminescent, biological applications in the progress of anticancer and antibacterial agents is investigated. The Cu and Zn bi-components modified (CuO-Cu 2 O)Cu/ZnO nanocomposites were synthesized via facile combustion route in the presence of controlled fuel to oxidizer ratio and were characterized by X-Ray Diffraction (XRD) patterns, Transmission electron microscopy (TEM), High resolution Transmission electron microscopy (HRTEM), Scanning Electron Microscopy (SEM), X-ray photoelectron Spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) and energy dispersive X-ray (EDX) analysis. The PL and UV–Visible diffused reflectance spectral (UV–Vis-DRS) techniques were used to measure the optical sensitivity and tuning of band gap in the samples. The excellent photocatalytic degradation of Methylene Blue and industrial waste water under Sunlight irradiation depends on the mass ratios of Cu/Zn. The findings show that the addition of a certain proportion of CuO, Cu 2 O, ZnO, and Cu can promote efficiency in Sunlight harvesting and separation of charge carriers. Process parameters namely catalyst quantity, dye concentration and a proposal for the mechanism of degradation pathway, experiments for trapping and enhancer are investigated. The study of photoluminescence, CIE and CCT calculations suggests that the present nanocomposite may find applications as phosphor material in warm white LEDs. The second segment of this study deals with the investigation of antibacterial performance of composites upon Gram-negative and Gram-positive bacteria. The results indicate that nanocomposites can be used in antibacterial control systems and as an important growth inhibitor in various microorganisms. The cytotoxic effect of the (CuO-Cu 2 O)Cu/ZnO (CCCZ11) nanocomposite was determined by colorimetric and flow cytometric cell cycle analysis. Our experimental results show that the nanocomposite can induce apoptosis and suppress the proliferation of HeLa cells. The applications of nanocomposites based on Cu, an abundant and inexpensive metal has created much interest in various multifunctional applications. [ABSTRACT FROM AUTHOR]

This work majorly aims to synthesize and also investigate the structural, optical, magnetic and optical features of ZrO 2 /ZnFe 2 O 4 nanocomposite. Here, different ratios of novel hetero-junction ZrO 2 /ZnFe 2 O 4 were synthesized by simple and fast solution combustion route. The X-ray diffraction results showed the formation of ZrO 2 and ZnFe 2 O 4 nanoparticles and ZrO 2 /ZnFe 2 O 4 nanocomposites without any impurity. The formation of hetero-junction effectively inhibits the photo-generated charge carrier recombination. The degradation of Indigo Carmine dye by ZrO 2 /ZnFe 2 O 4 photocatalyst was achieved through synergistic effects with 98% degradation and removal of 77% COD from the industrial dye waste water under Sunlight irradiation. Mixing of ferrites with zirconia greatly improves the photocatalytic activity that has been clearly proposed with the help of mechanism. ZZFO 12 NC exhibits better photocatalytic activity due to the combined facets of photo and Fenton activity. The exposure and enhancement of fingerprints in various surfaces are achieved by a modest, extremely sensitive and eco-friendly method. ZZFO12 NC offer great potential as an active photocatalyst for degradation of 54% of organic pollutant present in industrial waste water under natural Sunlight. [ABSTRACT FROM AUTHOR]

In recent years, key study was designing nanomaterials (NMs) with tunable properties in order to obtain high functional materials. For this purpose, an attempt with great effort has been put forward to synthesize ZrO 2 :Eu:Li (1–11 mol%) NM with varying concentration of Li+ ion that can have a control over phase, size, morphology, crystallinity, band gap and surface chemistry. More importantly, addition of Li as codopant influences the phase and crystallinity change with the change in concentration. However important challenges faced by this work was to understand the phase change, crystallinity, structural change and photocatalytic activity which has to be still explored. The synthesized NMs possess mixed phase and cubic phase with change in concentration of codopant which may be attributed to presence of defect states, micro strain, distortion of lattice. The energy band gap was found to decrease for 7 mol% NM attributed to the change in the phase. Porous morphology with variation in pore length was observed. Enhanced luminescence intensity with intense orange red emissions consistent to 5D 0 →7F j (j = 0 to 4) intra configurational f-f transitions was observed for ZrO 2 :Eu:Li+(1–11 mol%) nanophosphor excited at 394 nm. The visualization of latent fingerprints using ZrO 2 : Eu: Li+ 7mol% nanophosphor on several surfaces, the powder dusting technique was adopted. The enhanced fingerprint under UV light provides well resolved ridge patterns for the identification of individual latent finger prints using ZrO 2 :Eu:Li (7 mol%) with clear resolution. Lower charge transfer resistance with enhanced photocatalytic activity for decolourization of Rhodamine B with high pore length to allow multiple reflections under UV light irradiation for 7 mol% NM with reduced band gap and optimum luminescence intensity was observed. Hence, the synthesized ZrO 2 :Eu:Li (7 mol%) can be employed in forensic science towards latent fingerprint development, as a photocatalyst for environmental remediation and as luminescent material in display applications. [ABSTRACT FROM AUTHOR]

The goal of this research is to prepare novel, inexpensive, environment friendly and efficient crystalline CuO samples by green mediated combustion and co-precipitation routes towards environmental remediation and biomedical applications. The influence of preparation routes and Aloe barbadensis miller (Aloe vera) gel on the morphology, size, crystallinity, band gap, defects, photocatalytic, antibacterial, haemolytic and anticancer behaviour of CuO samples were explored. The PXRD, XPS, SEM, TEM, HRTEM and FT-IR were performed to confirm the formation of CuO samples. FTIR studies showed all possible bands of Aloe barbadensis miller gel. FTIR displaying the occurrence of new peaks and peak shifts in the CuO synthesized by green mediated combustion route compared to co-precipitation route is an evidence of the effective interactions between CuO and Aloe vera gel. The PL and UV–Vis-DRS techniques measured the optical sensitivity and tuning of band gap of the CuO samples. The crystallinity and surface properties dependent photocatalytic activities for decolourization of MB and RhB under both UV and Sunlight irradiation were investigated. The results indicated that green mediated synthesized CuO sample displayed high photocatalytic activity compared with co-precipitation route synthesized CuO sample, which mainly resulted from the low crystallinity and crystallite size (6 nm), narrow band gap (1.73 eV) and lower recombination of charge carriers. These synthesized CuO samples also demonstrate excellent antibacterial activity against the bacteria Gram-positive (S. aureus) and Gram-negative (E. coli). The present study probes into the cytotoxicity of CuO samples employing root cells of Allium cepa. In addition, we report the haemolytic activity on goat and human blood along with the implementation of green synthesized CuO sample using an Aloe barbadensis miller extract for the evaluation of anticancer activity in human cervical cancer (HeLa) cells with IC50 value of 310.1 μg/ml. Our studies focus on developing biosynthesized nanomaterials for environmental remediation and biomedical applications. [ABSTRACT FROM AUTHOR]

A facile solution combustion synthesis has been adopted to synthesize ZrO 2 /CuO nanocomposite oxides (NCO’s) by utilizing Oxalyl dihydrazide (ODH) as fuel. The X-ray diffraction patterns and TEM analysis reveals the presence of cubic ZrO 2 and CuO in ZrO 2 /CuO NCO’s. The NCO’s synthesized by simple, fast, highly sensitive and low-cost method is found to be an alternate to traditional luminescent powders for the detection and enhancement of finger marks in a broad range of surfaces. The photoluminescence analysis indicates that the present NCO is an effective blue component in display applications. The synthesized ZrO 2 /CuO (2:1) composite exhibited excellent photocatalytic activity towards the degradation of various dyes under Sunlight. In particular, Indigo carmine dye was chosen to explore the photocatalytic performance of prepared NCO’s under Sunlight illumination. It was found that ZrO 2 :CuO (2:1) NCO showed enhanced photocatalytic activity of 97% which was found to be 3.3 times 2.4 times and 1.5 times higher than that of pure ZrO 2 , CuO and commercial P25. This can be mainly attributed to the balance between the parameters, band gap, nature of morphology, crystallite size, defects and surface area which causes a slow electron-hole pair recombination rate with fast electron transfer ability. It opens new window to use this simple method to synthesize multifunctional character ZrO 2 -based composite materials in the area of photocatalysis particularly waste water treatment, display applications as well as a labeling agent to enhance latent fingerprints. [ABSTRACT FROM AUTHOR]

Eco-friendly, cost effective and bio template route was used for the preparation of cubic Gd 2 O 3 :Eu 3+ nanophosphors using Euphorbia tirucalli ( E. tirucalli ) plant latex as fuel. As – formed Gd 2 O 3 :Eu 3+ (7 mol%, 1–7 ml), calcined Gd 2 O 3 :Eu 3+ (7 mol%, 1–7 ml) and Gd 2 O 3 :Eu 3+ (1–11 mol%, 7 ml) samples were characterized using XRD, SEM and UV–Vis absorption spectrophotometer. With increase in latex concentration, the nanophosphor gets transformed from nano plates to rose – like nanoflowers with size varying from 20 to 30 nm. X-ray diffraction pattern of as – formed product shows hexagonal Gd (OH) 3 : Eu 3+ phase and it converts to pure cubic phase of Gd 2 O 3 :Eu 3+ on calcination at 600 °C for 3 h. Rietveld refinement of Gd 2 O 3 :Eu 3+ (7 mol%, 7 ml) revealed the presence of cations in the 8 b (0.25, 0.25, 0. 25) and 24 d positions (−0.0287, 0.00, 0. 25) and the anions in the 48 e positions (0.39, 0.15, 0. 37) with space group Ia -3(206). The photoluminescence intensities of transitions between different J levels depend on the symmetry of the local environment of Eu 3+ ion activators and the high ratio of intensity of ( 5 D 0 → 7 F 2 ) and ( 5 D 0 → 7 F 1 ) provides the conclusion that Eu 3+ ion occupies sites with a low symmetry and without an inversion centre. The chromaticity and the CIE coordinates were very close to the standard red color region. The absorption observed in the excitation spectra shows the suitability of the nanophosphor obtained in this study for getting excited in UV, NUV and visible regions for variety of display applications. Further, the Gd 2 O 3 :Eu 3+ (7 mol%, 1–7 ml) samples were experimented towards the photocatalytic behavior on Congo red (CR) and correlated with emission of PL intensity. The decolorization of dye was found to decreased from 83 to 54% with increase in the plant latex concentration. [ABSTRACT FROM AUTHOR]

The Present work involves the production of Eu3+ (1–11 mol %) doped MgNb 2 O 6 nanophosphors (NPs) by combustion technique using ODH as a fuel for the first time and well characterized. The average crystallite and the energy gap of the samples were found to be in the range of 20–45 nm and 4.65–5.66 eV respectively, TEM results reflects the same crystallite size values. The effect of doping was confirmed by the characteristic emission peaks recorded at ~535, 590, 614, 642 and 698 nm may be attributed to the 4f–4f intra shell transitions (5D 0 →7F j=0,1,2,3,4) of Eu3+ cations when bombarded at 395 nm energy. Judd–Ofelt parameters (Ω 2 , Ω 4), transition probabilities (A T), quantum efficiency (η), luminescence lifetime (τ rad) are discussed in detail. From the emission spectra, CIE (Commission International de I' Eclairage) chromaticity co-ordinates and Correlated color temperature (CCT) were estimated. Langmuir-Hinshelwood model was used to study the photocatalytic degradation of AR-88 dye. The above results confirmed that the present phosphor can be potentially used for display and photocatalytic applications. [ABSTRACT FROM AUTHOR]

We have reported Caralluma fimbriata extract induced simple single step green synthesis of pure and Gd loaded ZnO nanostructures towards the improvement of photocatalytic performance under both UV and Sunlight irradiation. Band gap of 2.97 eV and 95 Ω of charge transfer resistance displayed highest decolorization effectiveness of 90 and 98% underneath UV and Sunlight irradiation respectively for Gd loaded ZnO (1 mol%). The reason for the enhancement ascribed to electron trap generated by the special 7f electronic configuration of Gd 3+ which could increase the separation of the photo induced electron hole pairs and promoted charge transfer within the nanostructures. The photoluminescence spectrum consists of peak at ∼363 nm, ∼452 nm and ∼545 nm, color co-ordinates (0.14665, 0.31283) and average correlated color temperature ∼28465 K. Therefore, Gd-loaded nanostructures can be exercised as prospective photocatalyst as well as phosphors in display applications. [ABSTRACT FROM AUTHOR]

MgO:Fe 3+ (0.1–5 mol%) nanoparticles (NPs) were synthesized via eco-friendly, inexpensive and simple low temperature solution combustion route using Aloe vera gel as fuel. The final products were characterized by SEM, TEM and HRTEM. PXRD data and Rietveld analysis revealed the formation of cubic system. The influence of Fe 3+ ion concentration on the structure morphology, UV absorption, PL emission and photocatalytic activity of MgO:Fe 3+ NPs were investigated. The yellow emission with CIE chromaticity coordinates (0.44, 0.52) and average correlated color temperature value was found to be 3540 K which corresponds to warm light of NPs. The control of Fe 3+ on MgO matrix influences the photocatalytic decolorization of methylene blue (MB) under UV light. The enhanced photocatalytic activity of MgO:Fe 3+ (4 mol%) was attributed to dopant concentration, effective crystallite size, textural properties, decreased band gap and capability for reducing the electron–hole pair recombination. Further, the trends of inhibitory effect in the presence of different radical scavengers were explored. These findings open up new avenues for the exploration of Fe-doped MgO in eco-friendly water applications and in the process of display devices. [ABSTRACT FROM AUTHOR]

Facile and green route was employed for the synthesis of Y 2 O 3 :Dy 3+ (1–11 mol%) nanostructures (NSs) using Aloe vera gel as fuel. The formation of different morphologies of Y 2 O 3 :Dy 3+ NSs were characterized by SEM, TEM and HRTEM. PXRD data and Rietveld analysis evident the formation of single phase Y 2 O 3 with cubic crystal structure. The influence of Dy 3+ ion concentration on the structure morphology, UV absorption, PL emission and photocatalytic activity of NSs were investigated. NSs exhibited an intense warm white emission with CIE chromaticity coordinates (0.32, 0.33) and average CCT value ∼5525 K which corresponds to vertical day light. The control of Dy 3+ ion on Y 2 O 3 matrix influences the photocatalytic decolorization of Metanil Yellow as a model compound was evaluated. The enhanced photocatalytic activities of core shell structured Y 2 O 3 :Dy 3+ (1 mol%) was attributed to co-operation effect of dopant concentration, crystallite size, textural properties and capability for reducing electron–hole pair recombination. Further, the recycling catalytic ability of Y 2 O 3 :Dy 3+ (1 mol%) nanostructure was also evaluated and found promising photocatalytic performance with negligible decrease in decolorization efficiency even after sixth successive cyclic runs. Considering its green, facile synthesis and recyclable feature from an aqueous solution, the present Y 2 O 3 :Dy 3+ (1 mol%) nanophosphor can be considered as one of the ideal photocatalyst for various potential applications. [ABSTRACT FROM AUTHOR]