Enhanced Photo/Electrocatalytic Hydrogen Evolution by Hydrothermally Derived Cu-Doped TiO2 Solid Solution Nanostructures.

Highly efficient nanocatalysts with a high specific surface area were successfully synthesized by a cost-effective and environmentally friendly hydrothermal method. Structural and elemental purity, size, morphology, specific surface area, and band gap of pristine and 1 to 5% Cu-doped TiO2 nanoparticles were characterized by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), energy dispersive X-ray analysis (EDAX), inductively coupled plasma mass spectrometry (ICP-MS), liquid chromatography-high resolution mass spectrometry (LC-HRMS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET surface area, Raman spectroscopy, photoluminescence spectroscopy (PL) and UV-visible diffused reflectance spectroscopy (UV-DRS) studies. The XPS and EPR findings indicated the successful integration of Cu ions into the TiO2 lattice. UV-DRS and BET surface area investigations revealed that with an increase in dopant concentration, Cu-doped TiO2 NPs show a decrease in band gap (3.19-3.08 eV) and an increase in specific surface area (169.9-188.2 m2/g). Among all compositions, 2.5% Cu-doped TiO2 has shown significant H2 evolution with an apparent quantum yield of 17.67%. Furthermore, the electrochemical water-splitting study shows that 5% Cu-doped TiO2 NPs have superiority over pristine TiO2 for H2 evolution reaction. It was thus revealed that the band gap tuning with the desired dopant concentration led to enhanced photo/electrocatalytic sustainable energy applications.

Photo/electro catalytic green hydrogen production promoted by Ga modified Co0.6Cu0.4Fe2O4 nano catalysts.

The current work concentrates on the fabrication of Ga doped Co0.6Cu0.4Fe2O4 nanocatalysts via sol-gel auto-combustion (SGA) for the production of green and sustainable source of energy i.e., hydrogen through photocatalytic and electrocatalytic routes. Single-phased cubic crystal structure with Fd3m geometry was observed through XRD patterns. FESEM images show the aggregated and spherical shaped grains with distinct grain boundaries and average grain size of 1.04 and 1.39 µm for the Co0.6Cu0.4Fe2O4, and Co0.6Cu0.4Ga0.02Fe1.98O4 nanomaterials. Soft magnetic behaviour with a coercivity (Hc) and saturation magnetization (Ms) of 235.32-357.26 Oe and 54.65-61.11 emu/g was obtained for the produced nanomaterials. The estimation of photocatalytic nature for generating H2 was conducted using the sacrificial agents i.e., 0.128 M Na2S and 0.079 M Na2SO3. The analysis focused on measuring the maximum H2 generation was achieved by photocatalysts throughout three consecutive 4-h cycles. Out of all compositions, Co0.6Cu0.4Ga0.02Fe1.98O4 nanomaterial have the highest photocatalytic activity of 16.71 mmol gcat-1. However, the electrocatalytic behaviour of prepared Co0.6Cu0.4GaxFe2-xO4 (x = 0.00-0.03) electrocatalysts were determined for HER (Hydrogen evolution reaction) reaction. The overpotential values of Co0.6Cu0.4Fe2O4, Co0.6Cu0.4Ga0.01Fe1.99O4, Co0.6Cu0.4Ga0.02Fe1.98O4, and Co0.6Cu0.4Ga0.03Fe1.97O4 catalysts at 10 mA cm-2 were -0.81, -0.85, -1.03, and 1.21 V, correspondingly. Thus, at cathode current density of 10 mA/cm-2, an elevation in overpotential was noted, which indicates that the undoped Co0.6Cu0.4Fe2O4 (x = 0.00) electrocatalyst have remarkable electrocatalytic HER activity. Consequently, owing to photo/electro catalytic water splitting traits, the prepared catalysts are highly efficient for the green hydrogen generation.

Magnetically recoverable sol-gel auto-combustion developed Ni1-xCuxDyyFe2-yO4 magnetic nanoparticles for photocatalytic, electrocatalytic, and antibacterial applications.

Copper and dysprosium doped NiFe2O4 magnetic nanomaterials, Ni1-xCuxDyyFe2-yO4 (x = y = 0.00, 0.01, 0.02, 0.03), was prepared by utilizing sol-gel auto-combustion approach to inspect the photodegradation of methylene blue (MB) pollutant and also, to perform the electrocatalytic water splitting and antibacterial studies. The XRD analysis reveal the growth of a single-phase spinel cubic structure for produced nanomaterials. The magnetic traits show an increasing trend in saturation magnetization (Ms) from 40.71 to 47.90 emu/g along with a decreasing behaviour of coercivity from 158.09 to 156.34 Oe at lower and higher Cu and Dy doping content (x = 0.0-0.01). The study of optical band gap values of copper and dysprosium-doped nickel nanomaterials decreased from 1.71 to 1.52 eV. This will increase the photocatalytic degradation of methylene blue pollutant from 88.57% to 93.67% under natural sunlight, respectively. These findings clearly show that under natural sunlight irradiation for 60 min, the produced N4 photocatalyst displays the greatest photocatalytic activity with a maximum removal percentage of 93.67%. The electrocatalytic characteristics of produced magnetic nanomaterials for both HER and OER were examined with a Calomel electrode taking as a reference in a 0.5 N H2SO4 and 0.1 N KOH electrolyte. The N4 electrode demonstrated considerable 10 and 0.024 mA/cm2 of current density, with onset potentials of 0.99 and 1.5 V for HER and OER and also, have tafel slopes of 58.04 and 295 mV/dec, respectively. The antibacterial activity for produced magnetic nanomaterials was examined against various bacteria (Bacillus subtilis, Staphylococcus aureus, S. typhi, and P. aeruginosa) in which N3 sample produced significant inhibition zone against gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) but no zone of inhibition against gram-negative bacteria (S. typhi and P. aeruginosa). With all these superior traits, the produced magnetic nanomaterials are highly valuable for the wastewater remediation, hydrogen evolution, and biological applications.

Chemical fabrication, structural characterization and photocatalytic water splitting application of Sr-doped SnO2nanoparticles.

Semiconductor photocatalysis has gained considerable attention in recent years due to their enabling nature to convert solar energy into fuels of renewable hydrocarbon. However, many of them suffer from some drawbacks like the inability to visible light irradiation and wide band gaps. Herein, we have synthesized monophasic strontium (Sr) doped SnO2nanoparticles by a cost-effective and environmental friendly hydrothermal method. As-synthesized nanoparticles showed rutile crystalline structure with irregular and rough cubical shape and no other elemental impurities. Sr-doped SnO2nanoparticles show a constant decrease in bandgap with increasing dopant concentration, which is estimated for excellent photocatalytic activity. The photocatalytic water splitting of as-prepared Sr-doped SnO2nanoparticles for H2generation shows a large influence of the increasing dopant concentration related to the narrowing bandgap on H2generation rate. Hence, the tunable bandgap with adjusted dopant concentration indicates that band gap tuning through doping for produced nanostructures may open up a new opportunities for photocatalytic and other optoelectronic applications.

Modified, Solvothermally Derived Cr-doped SnO2 Nanostructures for Enhanced Photocatalytic and Electrochemical Water-Splitting Applications.

Cr-doped SnO2 nanostructures with a dopant concentration ranging from 1 to 5% have been successfully prepared using low-temperature modified solvothermal synthesis. The as-prepared nanoparticles showed a rutile tetragonal structure with a rough undefined morphology having no other elemental impurities. The particle shape and size, band gap, and specific surface area of the samples were investigated by scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, UV-visible diffused reflectance spectroscopy, and Brunauer-Emmett-Teller surface area studies. The optical band gap was found in the range of 3.23-3.67 eV and the specific surface area was in the range of 108-225 m2/g, which contributes to the significantly enhanced photocatalytic and electrochemical performance. Photocatalytic H2 generation of as-prepared Cr-doped SnO2 nanostructures showed improved effect of the increasing dopant concentration with narrowing of the band gap. Electrochemical water-splitting studies also stressed upon the superiority of Cr-doped SnO2 nanostructures over pristine SnO2 toward hydrogen evolution reaction and oxygen evolution reaction responses.

Formulation and Optimization of Candesartan Cilexetil Nano Lipid Carrier: In Vitro and In Vivo Evaluation.

PURPOSE: The objective of this study was to formulate and optimize Candesartan Cilexetil (CC) loaded nanostructured lipid carriers (NLCs) for enhanced oral bioavailability. METHOD: Glycerol monostearate (GMS), Oleic acid, Tween 80 and Span 40 were selected as a solid lipid, liquid lipid, surfactant and co- surfactant, respectively. The CC-NLCs were prepared by hot emulsion probe sonication technique and optimized using experimental design approach. The formulated CC-NLCs were evaluated for various physicochemical parameters and further optimized formulation (CC-NLC-Opt) was assessed for in vivo pharmacokinetic and pharmacodynamic activity. RESULTS: The optimized formulation (CC-NLC-Opt) showed particle size (183.5±5.89nm), PDI (0.228±0.13), zeta potential (-28.2±0.99mV), and entrapment efficiency (88.9±3.69%). The comparative in vitro release study revealed that CC-NLC-Opt showed significantly better (p<0.05) release and enhanced permeation as compared to CC-suspension. The in vivo pharmacokinetic study gave many folds increase in oral bioavailability than CC suspension, which was further confirmed by antihypertensive activity in a murine model. CONCLUSION: Thus, the results of ex vivo permeation, pharmacokinetic study and pharmacodynamics study suggest the potential of CC-NLCs for improved oral delivery.

Colloidal drug delivery system: amplify the ocular delivery.

CONTEXT: The ocular perceivers are the most voluntarily accessible organs in terms of location in the body, yet drug distribution to these tissues is one of the most intriguing and challenging endeavors and problematic to the pharmaceutical scientist. The most of ocular diseases are treated with topical application of conventional formulation, i.e. solutions, suspensions and ointment. Typically on installation of these conventional formulations, only <5% of the applied dose penetrates the cornea and reaches intraocular tissues, while a major fraction of the instilled dose is wastage due to the presence of many ocular barriers like external barriers, rapid loss of the instilled solution from the precorneal area and nasolacrimal drainage system. Systemic absorption caused systemic side effects varying from mild to life-threatening events. OBJECTIVE: The main objective of this review is to explore the role of colloidal delivery of drug to minimize the drawbacks associated with them. METHODS: This review provides an insight into the various constraints associated with ocular drug delivery, summarizes recent findings and applications of colloidal delivery systems, i.e. nanoparticles, nanosuspensions, liposomes, niosomes, dendrimers and contact lenses containing nanoparticles have the capacity to distribute ocular drugs to categorical target sites and hold promise to revolutionize the therapy of many ocular perceiver diseases and minimized the circumscription of conventional delivery. CONCLUSION: Form the basis of literature review, it has been found that the novel delivery system have greater impact to maximize ocular drug absorption, and minimize systemic absorption and side effects.