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In this study, an accurate, simple, economical and precise Reversed-Phase High Pressure Liquid Chromatography (RP-HPLC) method was developed for the simultaneous estimation of Ozenoxacin and Benzoic Acid in a pharmaceutical cream formulation, according to the International Conference on Harmonisation (ICH) guidelines. Chromatographic separation was achieved by gradient elution, on RP-HPLC Instrument, equipped with column C8 (150 mm × 4.6 mm, 5 μm particle size) using Ultra Violet (UV) detector at 235 nm wavelength, by using Mobile Phase A: triethylamine, trifloroacetic acid and water (1:1:1000) and Mobile Phase B: methanol and Diluent: water, acetonitrile and triethylamine (500:500:1), at flow rate 0.8 mL min−1; injection volume of 20 μL; column oven temperature 45 °C and sample temperature: 25 °C; Run time: 15 min. All the validation parameters were within the acceptance criteria, as per ICH requirements, for Ozenoxacin and Benzoic acid. Consequently, this method has found to be validated, simple, rapid and successfully applicable, to the simultaneous estimation of Ozenoxacin and Benzoic acid by RP-HPLC, for routine analytical testing in quality control, with a run time of 15 min and for future research studies. Forced degradation of Ozenoxacin cream 1% w/w formulation was performed and found that validated method has stability indicating potential that needs to be further studied.

Graphene oxide (GO) synthesized via modified Hummers method was studied for adsorption of methylene blue (MB) and malachite green (MG) dyes from aqueous solutions. It is hypothesized that electrostatic interactions between dye molecules and surface of GO will facilitate charge carrier movements and degrade the dye in an efficient way. The as synthesized GO was characterized using various characterization techniques such as XRD, Raman, FTIR, UV–Vis, SEM and EDAX. The experimental results suggest that dye removal percentage will increase with increase in adsorbent dosage, time as well as solution pH and the process was exothermic in nature. The adsorption data at 293 K could be fitted by Langmuir equation with a maximum adsorption amount of 119.04, 102.4 mg/g and Langmuir adsorption equilibrium constant of 1.58, 0.867 L/mg for MB and MG dyes, respectively. The outcomes of present article will help not only to understand the adsorption characteristics of GO on MB and MG dyes but also paves path towards development of highly oxidized GO surface for degradation of complex dyes.

Nanocrystalline zinc oxide (ZnO) photocatalyst has been synthesized by a simple solution combustion method using zinc nitrate as the oxidizer and urea as the fuel. Effect of fuel to oxidizer ratio and ignition temperature on the mechanism of combustion synthesis, crystallinity, morphology, surface area, and optical properties were investigated by thermal analysis, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Diffuse reflectance UV–Visible spectra and Photoluminescence analyses. Photocatalytic activity of the synthesized materials was evaluated by degrading an azo dye at ambient temperature and solution pH. The prepared photocatalysts at the fuel-rich condition possess small crystallite size and more surface area; consequently, a higher photocatalytic dye degradation capability.The powder samples synthesized at the fuel-oxidant ratio of 1.8 and the ignition temperature at 400 °C have shown the maximum percentage (99%) of dye degradation in 180 min. The pseudo-first order photocatalytic dye degradation rate constant of a catalyst sample synthesized at the fuel-oxidant ratio of 1.8 was 0.0253 min−1and it is 3.14 and 2.88 times higher than that of samples synthesized at fuel-oxidant ratios of 0.6 and 1.The outcomes of the present article help to design more pronounced experiments for the synthesis of photocatalysts by varying ignition temperatures and fuel amounts.

Stabilization of different morphologies of iso-material native/non-native heterostructures is important for electron-hole separation in the context of photo-electrochemical and opto-electronic devices. In this regard, we explore the stabilities of different morphologies of rutile ("native", ground state phase) and anatase ("non-native" phase) TiO2 heterostructures through (1) seed-mediated growth and (2) a thermally induced arrested phase transition synthesis protocol. Furthermore, the experimental results are analyzed through a combination of Density Functional Tight Binding (DFTB) and Finite Element Model (FEM) methods. During the seed-mediated growth, anatase is grown over a polydispersed and polycrystalline rutile core through thermal treatment yielding core-shell, Janus and yolk-shell iso-material heterostructures as observed from HRTEM. The arrested phase transition of anatase to rutile at different annealing temperatures yields rutile crystals in the subsurface region of the anatase and rutile/core-thin anatase/shell heterostructures but does not yield a Janus structure. Small particles that can be modeled via DFTB computations suggest that: (1) a heterostructure of the rutile/core-anatase/shell is energetically more stable than the anatase/core-rutile/shell or any other Janus configuration, (2) the off-centered rutile/core-anatase shell is more favorable to the mid-centered rutile/core-anatase shell and (3) Janus heterostructures can be stabilized when the mass ratio of the rutile seed to anatase overgrowth is high. FEM simulations, performed to evaluate the importance of stress relaxation in bicrystalline materials without defects, suggest that Janus structures can be stabilized in larger particles. The present studies add to the heuristics available for synthesizing iso-material heterostructures.

In contemporary research, semiconductor composite materials, i.e., combination of different semiconductor materials, play an important role in extracting needful energy from existing renewable energy forms. For example, “heterostructure” composite assemblies facilitate faster charge carrier transport and therefore improve the efficiency of the electro-/photoelectrochemical processes/devices due to synergistic interaction and synchronized charge transport across material interfaces that have formed in composite assembly. Herein, we report type-I heterostructure consists of TiO2 and Fe2O3 for crystal violet dye degradation and water splitting studies via electrochemical route. The rationale in choosing the above materials (TiO2, Fe2O3) in the present study will not only account stability, nontoxicity, and high oxidation power but also facilitate the fast charge carrier movements due to proper band edge alignments. Synthesized TiO2, Fe2O3, and TiO2/Fe2O3 nanoparticle assemblies were fabricated as electrodes on titanium (Ti) and indium tin oxide (ITO) substrates and used as anode in electrochemical analysis. Complete decolorization was achieved with all the fabricated electrodes and higher rate of degradation was achieved with composite electrode (Ti/TiO2/Fe2O3) than individuals (bare Ti, Ti/TiO2, Ti/Fe2O3). Further, the same composite electrode shows better performance toward electrochemical water splitting in comparison with individual electrodes.

Electrochemical potential gradients that are established due to appropriate band edge alignment in heterostructures can synchronize the movement of electron and hole in opposite direction. Such synchronization is critical for efficient photoelectrochemical devices and can be achieved by tailoring the interface of heterostructures. To this end, we fabricate a tailored interface of Si–Au–TiO 2 heterostructure over stainless steel ((Si–Au–TiO 2 )/SS) for effective charge carrier separation. The fabricated electrode possesses the following tailored interfaces to enhance the charge-carrier separation/transport: 1) gold nanoparticles form interface (sandwiched) with Si as well as TiO 2 ; 2) Si, Au, and TiO 2 form the interface with SS, 3) Si–TiO 2 , and Si–Au interface facilitates the quenching of h + generated in Si (via electron transfer from TiO 2 and Au to Si) which facilitates electron transport to counter electrode for hydrogen generation, and 4) TiO 2 forms the interface with the electrolyte solution to facilitate hole transport. Photoelectrochemical (PEC) measurements of (Si–Au–TiO 2 )/SS heterostructure exhibits higher performance compared to other heterostructures ((Au–Si)/SS, (Au–TiO 2 )/SS, (Si–TiO 2 )/SS, TiO 2 /Au/Si/SS, and Si/Au/TiO 2 /SS), substantiating the importance of synchronized charge transport in PEC systems. Further, electrochemical impedance spectroscopy (EIS) studies also support the synchronized charge transport in the tailored heterostructure ((Si–Au–TiO 2 )/SS) compared to control samples. The calculated applied bias to photo-conversion efficiency (ABPE) of ~0.4%@~0.9 V applied bias, intrinsic solar to chemical conversion efficiency (ISTC) of ~0.085 (or 8.5%) @1.66 V vs. RHE and electrical and solar power-to-hydrogen (ESPH) conversion efficiency of ~3.3%@~1.0 V applied bias.

Semiconductor-mediated photoelectrochemical (PEC) water splitting to generate hydrogen and oxygen has gained tremendous attention as it has the capability to overcome the world energy crisis. However, limited solar light absorption and a high charge carrier recombination rate are major bottlenecks in achieving the desired efficiency of PEC devices. Fabrication of semiconductor–metal/metal oxide heterostructure holds a great promise to overcome these bottlenecks as it facilitates solar light absorption, separation, and transport of charge carriers. To this end, we demonstrate a fabrication methodology to design stable tailored heterostructures via click chemistry. To test the proposed methodology, we choose gold (Au), rutile-TiO2 (R-TiO2), and anatase TiO2 (A-TiO2) as model system and designed tailored triad heterostructure, i.e., Au@R-TiO2@A-TiO2 over stainless steel, and demonstrated its application in photoelectrochemical (PEC) water splitting. We hypothesize that the presence of Au and R-TiO2/A-TiO2 in...

Metallic nanoparticles (MNP) are utilized as electrocatalysts, cocatalysts, and photon absorbers in heterostructures that harvest solar energy. In such systems, the interface formed should be stable over a wide range of pH values and electrolytes. Many current nonthermal processing strategies rely on physical interactions to bind the MNP to the semiconductor. In this work, we demonstrate a generic chemical approach for fabricating highly stable electrochemically/photocatalytically active monolayers and tailored multilayered nanoparticle structures using azide/alkyne-modified Au, TiO2, and SiO2 nanoparticles on alkyne/azide-modified silicon, indium tin oxide, titania, stainless steel, and glass substrates via click chemistry. The stability, electrical, electrochemical, and photocatalytic properties of the interface are shown via electrochemical water splitting, methanol oxidation, and photocatalytic degradation of Rhodamine B (RhB) dye. The results suggest that the proposed approach can be extended for the large-scale fabrication of highly stable heterostructure materials for electrochemical and photoelectrocatalytic devices.