Use of renewable waste material for water treatment is an area of interest. An attempt has been made for preparation of Dairy industry waste Ghee residue (GR) based biogenic adsorbent for removal of dye present in water/waste water. This novel approach contributes in valorisation of dairy industry by- product Ghee residue. The ghee residue was first converted into carbon and processed with the titanium precursor and rare earth metal. This combination yields GR-C/TiO2/Eu3+ adsorbent. A series of adsorbing material was prepared by differing loading of Eu3+ keeping ratio of RG-C and TiO2 constant. Synthesized adsorbents were subjected to characterization studies such as X-Ray Diffraction (XRD) spectroscopy, Brunauer Emmett Teller-Surface Area (BET-SA), Scanning Electron Microscopy (SEM), Fourier Transformed Infra Red spectroscopy (FTIR) etc. XRD pattern shows formation of crystalline anatase phase of TiO2 with average particle size of 34.9494 nm. SEM image also confirms irregular morphology with particles in nanometer range. BET-surface area of GR-C/TiO2/Eu3+ (1

This paper presents a comprehensive review of the challenges, advancements, and prospects in the synthesis, characterization, and fabrication of white light phosphor matrices for energy-efficient lighting applications. The research in this field has experienced rapid growth, with a focus on innovating phosphor materials possessing enhanced properties such as cost-effectiveness, color purity, chemical and thermal stability, and quantum efficiency. Emphasizing the problem of white light generation using inorganic phosphors, the study explores structure-property relationships across a diverse range of phosphor materials. Additionally, it provides insights into radiative and non-radiative relaxation mechanisms. Various phosphors emitting light across different colors (blue, green, yellow, and red) are systematically categorized based on their host matrices, including phosphates, aluminates, borates, silicates, and non-oxide hosts. White light phosphor matrices hold promising prospects for the development of future energy-saving solid-state lighting sources, owing to their inherent advantages such as low driving voltages, exceptional efficiency and brightness, and large area coverage. While commercialization efforts have garnered significant attention from both industrial and academic sectors, this study underscores the importance of advancing competent phosphors to meet the evolving demands in this field.

Metal nonoparticles stabilized by polymers is emerging as a new class of materials having entirely new physico-chemical properties as that of bulk and atom both. Stabilizers play important role in protecting the nanoparticles and also contributes in improvising the overall surface area. Chitosan, a natural polymer is selected as a stabilizer for the synthesis of iron containing nanoparticles. These nonoparticles are thoroughly characterized by using BETsurface area, FTIR, TEM and XPS. TEM image is showing well dispersed nanofibers with average size of 13nm. XPS data supports the formation of Fe2O3 type structure with O1s binding energy at 534.5 eV and Fe 2P3/2 and Fe 2P1/2 binding energies at 712eV and 723.2 eV. BET Surface area value is 36.72m2 /g with pore size of 145.16 and pore volume of 0.1332 cm3 /g. This synthesized nanomaterial was evaluated for photocatalytic hydrogen generation via water splitting reaction. Iron containing nanoparticles are showing excellent photocatalytic activity with hydrogen generation yield of 55.5 mmoles h-1g -1 of photocatalyst. The nanoparticles are magnetically retrievable and hence can be separated effectively from heterogeneous system.

Rare earth-activated fluoride phosphors have generated attention in recent years in the field of solid-state lighting and solar cell efficiency enhancement.

In this study, we have reported thermoluminescence (TL) properties and trapping parameters of Eu3+ and Dy3+ - doped K3Ca2(SO4)(3)Cl phosphors. The host materials have been prepared by a simple cost-effective wet chemical method. The TL glow curves of gamma-irradiated halo-sulfate phosphors are observed at a constant heating rate of 5 degrees C/s and a dose rate of 0.3712 kGy/hr for 3Gy dose. The TL glow curve of synthesized phosphor samples has a simple glow curve with an isolated peak. K3Ca2(SO4)(3)Cl:Eu3+ phosphors show TL response linearity in the range of 12Gy-62Gy. But, K3Ca2(SO4)(3)Cl:Dy3+ phosphors show TL response linearity in the range of 12Gy-87Gy. In this work, we have also calculated the trapping parameters of synthesized phosphors by different methods, such as Chen's peak shape method, Initial Rise (IR) Method, Ilich method, E-Shape glow curve method, E-Luschik methods, E-Halperin and Braner method. An easy method of synthesis, simple glow curve with isolated peak, efficient dose response, low value of activator concentration and low fading suggests that these phosphors may be potential candidates for thermoluminescence dosimetry and image storage.

Effect of photodeposition of AuNPs (gold nanoparticles) on TiO2, CeO2, Cu2O and Fe3O4 supports has been illustrated on sacrificial donor based hydrogen evolution. The synthesized samples were characterized by diffuse reflectance spectroscopy (DRS), and transmission electron microscopy (TEM). Highest photocatalytic activity was exhibited by Au/TiO2 followed by Au/Fe3O4, Au/CeO2 and Au/Cu2O. Au/TiO2 under optimized conditions has shown significantly high photocatalytic activity under both UV visible and visible radiation. Au/TiO2 shows hydrogen evolution rate of 920 mu mol h(-1) and 32.4 mu mol h(-1) under UV-visible and visible radiation, respectively. Significant enhancement in hydrogen evolution rate under visible light is very encouraging and may be attributed to polydispersed nature of AuNPs wherein larger particles facilitate light absorption and the smaller function as catalytic sites. Further studies are in progress to study the influence of various parameters on photocatalytic activity of Au/TiO2. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

In the present study, we have synthesised carbon nanoparticles (CNPs) through a relatively simple process using a hydrocarbon precursor. These synthesised CNPs in the form of elongated spherules and/or agglomerates of 30–55 nm were further used as a support to anchor platinum nanoparticles. The broad light absorption (300–700 nm) and a facile charge transfer property of CNPs in addition to the plasmonic property of Pt make these platinized carbon nanostructures (CNPs/Pt) a promising candidate in photocatalytic water splitting. The photocatalytic activity was evaluated using ethanol as the sacrificial donor. The photocatalyst has shown remarkable activity for hydrogen production under UV-visible light while retaining its stability for nearly 70 h. The broadband absorption of CNPs, along with the Surface Plasmon Resonance (SPR) effect of PtNPs singly and in composites has pronounced influence on the photocatalytic activity, which has not been explored earlier. The steady rate of hydrogen was observed to be 20 mmol h�1 with an exceptional cumulative hydrogen yield of 32.16 mmol h�1 g�1 observed for CNPs/Pt, which is significantly higher than that reported for carbon-based systems.

Nanocrystalline PrFeO3 perovskite type orthoferrite was synthesized at 700°C by using three different synthesis methods, namely sol–gel, template and combustion method. The synthesized materials were characterized by XRD, BET-SA, SEM, HRTEM, XPS, FTIR and UV-DRS techniques to understand their physico-chemical properties. Characterization data reveal the formation of nanocrystalline PrFeO3 perovskite composition with improved physical properties, possibly due to lower synthesis temperature used. PrFeO3 synthesized by sol–gel method consists of crystallite size of about 20 nm with absorption maxima at 595 nm wavelength in visible light range. This photocatalyst shows hydrogen generation of about 2847 μmol.g−1.h−1, under visible light irradiation in ethanol–water system. The photocatalyst was further investigated for various operational parameters such as photocatalyst dose variation, illumination intensity, time, etc. in a view to optimize the hydrogen generation as well as to understand mechanistic aspects. This material appears to follow a semiconductor type mechanism for ethanol-assisted visible light photocatalyic water-splitting and can also be an interesting candidate to develop hetero-junction type photocatalysts.

Titanium dioxide was supported on mesoporous silica and promoted with Pt and Ru. The supported photocatalysts show high surface area and better photocatalytic activity in visible light as compared to the benchmark Degussa P25. These photocatalysts were characterized using XRD, BET-SA, and UV-DRS techniques. The surface area of supported photocatalyst was 140.6 m(2)/g which is higher than Degussa P-25. Supported photocatalyst was evaluated for hydrogen evolution via water splitting reaction using ethanol as a sacrificial donor. Hydrogen yield observed is 4791.43 mu mol/h/g of TiO2 and that for P-25 is 161 mu mol/h/g of TiO2 under visible light irradiation. The value is 30 times higher than benchmark material Degussa P-25. This photocatalyst is also found stable up to 24 h without replenishing with sacrificial donor ethanol. However silica gel/TiO2/Ru does not show any exciting result for hydrogen generation. The effect of various operating parameters like photocatalyst loading, Illumination time and intensity of light on supported photocatalyst also has been studied. (C) 2013 Elsevier Ltd. All rights reserved.

Carbonic anhydrase (CA) has been immobilized on chitosan stabilized iron nanoparticles (CSIN) for the biomimetic carbonation reaction. CSIN was characterized using scanning electron microscope, energy dispersive X-ray, X-ray diffraction spectroscopy, and Fourier transform infrared analysis. The effect of various parameters such as pH, temperature and storage stability, on immobilized CA was investigated using a p-NPA assay. Kinetic parameters of immobilized and free CA (K m and V max values) were also evaluated. The K m and V max for immobilized CA was 1.727 mM and 1.189 μmol min−1 ml−1, respectively, whereas for free enzyme the K m and V max was 1.594 mM and 1.307 μmol min−1 ml−1, respectively. It was observed that the immobilized enzyme had longer storage stability and retained 50 % of its initial activity upto 30 days at room temperature. CA immobilized on CSIN has been used for hydration of CO2, and the results were validated by using a gas chromatographic method. Proof of concept has been established for the biomimetic carbonation reaction. Immobilized CA show reasonably good CO2 sequestration capacity of 21.55 mg of CaCO3/mg of CA as compared to CO2 sequestration capacity of 34.92 mg of CaCO3/mg of CA for free CA respectively, under a limiting concentration of CO2 (14.5 mg of CO2/10 ml).

In this study, nitrogen-doped mesoporous titania was synthesized by templating method using chitosan. This biopolymer chitosan plays the dual role of acting as a template (which imparts mesoporosity) and precursor for nitrogen. BET-SA, XRD, UV-DRS, SEM, and FTIR were used to characterize the photocatalyst. The doping of nitrogen into TiO2 lattice and its state was substantiated and measured by XPS. The photocatalytic activity of the prepared N-doped mesoporous titania for phenol and o-chlorophenol degradation was investigated under solar and artificial radiation. The rate of photocatalytic degradation was observed to be higher for o-chlorophenol than that of phenol. The photodegradation of o-chlorophenol was 98.62% and 72.2%, while in case of phenol, degradation to the tune of 69.25% and 30.58% was achieved in solar and artificial radiation. The effect of various operating parameters, namely, catalyst loading, pH, initial concentration and the effect of coexisting ions on the rate of photocatalytic degradation were studied in detail.

Nano structured metal oxides including TiO2, Co3O4 and Fe3O4 have been synthesized and evaluated for their photocatalytic activity for hydrogen generation. The photocatalytic activity of nano cobalt oxide was then compared with two other nano structured metal oxides namely TiO2 and Fe3O4. The synthesized nano cobalt oxide was characterized thoroughly with respect to EDX and TEM. The yield of hydrogen was observed to be 900, 2000 and 8275 mu mol h(-1) g(-1) of photocatalyst for TiO2, Co3O4 and Fe3O4 respectively under visible light. It was observed that the hydrogen yield in case of nano cobalt oxide was more than twice to that of TiO2 and the hydrogen yield of nano Fe3O4 was nearly four times as compared to nano Co3O4. The influence of various operating parameters in hydrogen generation by nano cobalt oxide was then studied in detail. Copyright (c) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Immobilization of chlorophyll on different functionalized mesoporous materials has been attempted. The replacement of butanediol with monoethanol amine has resulted in increase in chlorophyll loading by a factor of two. The maximum immobilization of chlorophyll was on MCM-41 functionalized with monoethanolamine MCM-41/MEA/Chl) as compared to other mesoporous materials. This material has been characterized using XRD, UV–vis diffuse reflectance spectroscopy, scanning electron microscopy (SEM-EDX) and fluorescence spectroscopy. The photocatalytic reduction of methyl orange (MO) was studied using MCM-41/MEA/Chl as photocatalyst under the visible light. The photocatalytic reduction of MO was 0.396mg/g of MCM-41/MEA/Chl photocatalyst as compared to 0.508mg/g of TiO2 for that of Degussa P-25 photocatalyst. The effect of various operating parameters like catalyst loading, initial concentration and intensity of light has also been studied. Photocatalytic property of chlorophyll-based photocatalytic material indicates that chlorophyll acts as a reaction center, which absorbs visible light and generates electron, which is transferred to different electron acceptors reducing MO into derivative of hydrazine.

N-doped mesoporous titania was synthesized using templating method. Biopolymer chitosan was used as a template and also as a nitrogen source along with ammonium hydroxide. Three different types of N-doped mesoporous titania were synthesized by varying composition of chitosan and titania precursor. These photocatalysts were characterized using XRD, BET-SA, FTIR, UV-DRS, SEM-EDX and XPS analysis. The photocatalytic activity of mesoporous titania was studied by methyl orange (MO) photoreduction reaction. From the experimental results it was observed that the N-doped mesoporous titania (1:2) gives the highest photocatalytic reduction of MO as compared to N-doped mesoporous titania prepared with (1:1) and (1:3) stoichiometry. This could be due to the optimal level of 'N' incorporation in the N-doped mesoporous titania (1:2).Photocatalysts reduce the MO dye into derivative of hydrazine. Photoactivity of N-doped mesoporous titania (1:2) is 1.0721 mg of MO reduced per g of TiO2 vis-a-vis 0.508 mg of MO reduced per g of TiO2 for Degussa P25 photocatalyst. The effect of various operating parameters like photocatalyst loading. initial concentration and intensity of light also has been studied. (C) 2009 Elsevier B.V. All rights reserved.