UV Diffuse Reflectance Spectroscopy Research Articles

A New Zinc-based Metal Organic Framework as a Stationary Phase for Thin Layer Chromatography


 Metal organic frameworks (MOFs) are a variety of micro-porous materials which have high surface area, and permanent porosity making them possible options as chromatographic stationary phases. Herein we reported the synthesis and characterization of a new MOF structure and its utilization as a stationary phase for thin layer chromatography (TLC). [Zn(BMAB).DMF]n is a zinc-based MOF with an organic linker consists of chemically distinct binding groups which is 4-{[(1h-1,2,3-benzotriazol-1-yl)methyl]amino}benzoic acid (BMAB). This MOF was synthesized using ultra sound assisted reaction process, then activated via solvent exchange protocol to preserve its porous structure. FT-IR, UV-diffuse reflection spectroscopy (UV-DRS) and differential scanning calorimetry (DSC) were performed to characterize the synthesized MOF. Integrated data from "loss on desolvation" and atomic absorption spectrophotometry (AAS) measurements were used to define the chemical composition of the synthesized material. A specific surface area of 122.9 m2/g was determined for the activated MOF using methylene blue langmuir isotherm method. TLC plates were prepared from the activated form of the structure to investigate its chromatographic characteristics by utilizing it to separate a model mixture of benzidine and o-tolidine using n-propanol: Chloroform: Acetonitrile (50:30:20, v/v/v) as a mobile phase. The retardation factors (Rf), separation factor, and resolution (Rs) were determined via densitometric method at 310 nm to be 0.45 and 0.63 (α=2.08, Rs=1.61) for o-tolidine and benzidine; respectively. The plate was then visualized using iodine chamber method to confirm a successful separation.

Synthesis, spectral and structural studies on NiS2PN and NiS2P2 chromophores and use of Ni(II) dithiocarbamate to synthesize nickel sulfide and nickel oxide for photodegradation of dyes

The substitution of one of the dithiocarbamate ligands in homoleptic [Ni(dtc)2] (1) complex (dtc = N,N-di(4-methoxybenzyl)dithiocarbamate) with the phosphine ligands gave heteroleptic [Ni(dtc)(PPh3)(NCS)] (2), [Ni(dtc)(PPh3)2] ClO4 (3) and [(dtc)(dppe)] ClO4 (4) complexes. The complexes 2–4 were characterized by elemental analysis, spectroscopy and single crystal X-ray diffraction analysis. Single crystal X-ray diffraction studies revealed that 2–4 adopt distorted square planar geometry. Non-covalent interactions in 2–4 were quantified using Hirshfeld surface analysis. The study of single crystal X-ray diffraction of 2–4 shows that various interactions such as C–H⋯π (chelate), C–H⋯π, C–H⋯O and C–H⋯S among molecules of complexes 2–4, participate in cooperative way to stabilize the supramolecular interactions. DFT calculations were used to determine the electronic structure and properties of 2. The HOMO-LUMO energy difference (2.7445 eV) is observed to be small which shows the low kinetic stability of 2. Nanoparticles of nickel sulfide and nickel oxide were successfully synthesized by solvothermal and thermal decomposition of 1, respectively and characterized by powder X-ray diffraction (PXRD), High Resolution Scanning Electron Microscopy (HRSEM), Energy Dispersive Spectroscopy (EDS) and UV Diffuse Reflectance Spectroscopy (UV-DRS). The photocatalytic activity of both nanoparticles was investigated for degradation of methylene blue and rhodamine 6G under UV irradiation. The results revealed that the nickel oxide has higher photocatalytic activity than nickel sulfide.

Effect of cobalt doping on the electrochemical performance of trimanganese tetraoxide

Nanostructured transition metal oxides (TMO) are potential materials widely explored by researchers for energy storage applications. In this study, spinel trimanganese tetraoxide (Mn3O4) and cobalt doped trimanganese tetraoxide (Co-Mn3O4) was synthesized by using a simple solvent assisted hydrothermal route. Pure Mn3O4 and Co-Mn3O4 nanomaterials were characterized by an x-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), UV-diffuse reflectance spectroscopy (UV-DRS), field emission scanning electron microscope (FESEM), and high resolution transmission electron microscope (HRTEM). XRD analysis revealed the body centered tetragonal spinel structure of Mn3O4 and Co-Mn3O4 with a space group as l41/amd (141) and an approximate crystallite size of 45–33 nm. The presence of an Mn–O bond vibration was confirmed using FTIR and the band gap properties were analyzed through UV-DRS. Surface morphology and average grain size were examined using FESEM and HRTEM micrographs as nanosquares and nanospheres with diameter 126 nm and 118 nm, respectively. Electrochemical properties of Mn3O4 and Co-Mn3O4 were evaluated using cyclic voltammograms, charge–discharge curves, and electrochemical impedance spectra (EIS). Pure Mn3O4 showed a specific capacitance of 971 F g−1 at 0.1 A g−1 current density while Co-Mn3O4 achieved relatively higher specific capacitance of 1852 F g−1 at the same current density. It is observed that the increased specific capacitance of Co-Mn3O4 mainly arises from the doping effect. Electrochemical analysis shows that the Co doped Mn3O4 nanomaterials can be a promising electrode material for supercapacitor.

Photocatalytic, nitrite sensing and antibacterial studies of facile bio-synthesized nickel oxide nanoparticles

In the present work, Nickel oxide nanoparticles (NiO NPs) were synthesized using leaves extract of C. gigantea through a solution combustion method. The NiO NPs were characterized through analytical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). The XRD results revealed rhombohedral structured crystallites with average size of 31 nm. SEM and TEM images indicate that the nanoparticles are agglomerated with an asymmetrical shape. The optical energy bandgap of 3.45 eV was estimated using UV-diffused reflectance spectroscopy (UV-DRS). The synthesized NiO NPs have shown superior photodegradation for methylene blue (MB) dye. Further, the antibacterial activity of the prepared nanoparticles was tested against E.coli and S.aureus bacterial strains. In addition, nanoparticles were utilized for electroanalytical applicability as a novel non-enzymatic sensor in the trace level quantification of nitrite. The proposed nitrite sensor showed wide linearity in the range 8–1700 μM and good stability with a lower detection limit of 1.2 μM. • Nickel oxide nanoparticles (NiO NPs) were synthesized using Calotropis gigantea through solution combustion method. • The prepared NPs were characterized using FT-IR, XRD, SEM, EDAX, HR-TEM and voltammetric techniques. • The NiO NPs showed good performance in degradation of MB dye and better antibacterial activity against E . coli and S . aureus bacterial strains. • The NiO NPs modified electrode showed the excellent electro catalytic behavior in the electrochemical sensing of nitrite with detection limit of 1.2 μM.

Photo-responsive azo-functionalised flexible polymer substrate for liquid crystal alignment

ABSTRACT An azobenzene derivative containing a dimethylchlorosilane end group was chemically attached to a flexible polymer substrate to create permanent photo alignment layer. The commercially obtained polymer substrate (overhead projector film) was characterised and found to contain cellulose acetate as the main component. Surface functionalization of the substrate was confirmed through X-ray photoelectron spectroscopy (XPS), attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy, water contact angle (CA) and atomic force microscopy (AFM) techniques. Photo-isomerisation behaviour of the azo-layer on the polymer substrate was additionally confirmed by UV-diffuse reflection spectroscopy (UV-DRS). Further, the azo-modified flexible substrate was analysed for the orientation of the bulk liquid crystal (LC) sample and tuning the LC orientation by utilising photo-switching behaviour of the azo-layer on the substrate.

Green Synthesis of Zinc Oxide Nanoparticles using Garlic skin extract and Its Characterization

Plant-mediated synthesis of metal oxide nanoparticles is a promising alternative to the traditional method of physical and chemical synthesis. In this paper, we report the green synthesis of zinc oxide nanoparticles (ZnONPs) by a biological method. During the study, Zinc oxide nanoparticles were synthesized by Allium sativum skin (garlic skin) extract. Formation of zinc oxide nanoparticles has been confirmed by UV-visible spectroscopy, UV diffuse reflectance spectroscopy (UV-DRS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope with Energy dispersive X-ray studies (EDX) and transmission electron microscope (TEM), Atomic force Microscopy (AFM), Brunauer-Emmet-Teller (BET), Thermogravimetric analysis (TGA). UV-vis spectroscopy confirms the synthesis of zinc oxide nanoparticles and showed the characteristic of absorption peak at 370nm. The scanning electron microscope and Transmission electron microscope confirms the formation of the rod and hexagonal shaped nanoparticles having average size 7.77 nm. Energy dispersive X-ray analysis states the formation of highly pure zinc oxide nanoparticles. The zinc oxide nanoparticles synthesized using garlic skin are expected to have applications in biotechnology, biomedical, catalysis, coatings, sensors and water remediation. This green approach for the synthesis is a cheap, novel, eco friendly and convenient method.

An antibacterial activity of Bauhinia racemosa assisted ZnO nanoparticles during lunar eclipse and docking assay

In the present work it has been seen that Bauhinia racemosa assisted in fabrication of ZnO Nanoparticles (ZnO NPs) used for docking and antibacterial assay. ZnO NPs was confirmed through UV-diffuse reflectance spectroscopy by achieving peak at 370 nm. Structural authentication was confirmed by XRD, SEM and TEM. Fabricated ZnO NPs was used to investigate an antibacterial activity during lunar eclipse. The activity was checked against Proteus vulgarus, Escherichia coli, Staphylococcus aureus, and Klebsiella pneumoniae, and observed magnificent result against K. pneumoniae. Besides, remarkable antioxidant activity was performed by using DPPH. In addition a molecular docking study of ZnO NPs was also conducted.

Carbon-doped titanium dioxide nanoparticles: A facile synthesis, characterization and their photocatalytic activity

In the present study, carbon-doped titanium dioxide (C-TiO2) nanoparticles (NPs) have been synthesized by utilizing the sol-gel method. Herein, polymer was used as the source for carbon-doping. The synthesized C-TiO2 was characterized by UV-Diffused Reflectance spectroscopy (UV-DRS). A significant decrease in the band gap of pure TiO2 was observed upon doping the pure TiO2 with carbon. The red shift in absorbance values depicted visible-light absorption which was investigated by photocatalytic degradation of the cationic dye, methylene blue (MB). The effectual degradation of the dye depicted the increased photocatalytic activity of the nanoparticles upon carbon-doping.

An effective photocatalytic and photoelectrochemical performance of β/γ-MnS/CdS composite photocatalyst for degradation of flumequine and oxytetracycline antibiotics under visible light irradiation

Herein, we report the MnS, CdS and MnS/CdS nanoparticles prepared by precipitation method. The as-synthesized particles were characterized using by scanning electron microscope, X-ray diffraction, UV-diffuse reflectance spectroscopy, photoluminescence, X-ray photoelectron spectroscopy and photoelectrochemical technique. MnS/CdS composite combination enhanced the optical, photocatalytic, and photoelectronic properties of the samples. Photocatalytic performances of the samples were evaluated under visible light irradiation. The photoelectrode activity of all samples was also investigated. MnS/CdS composites were found as efficient photocatalysts under visible light. The enhanced photocatalysis of the composites was attributed to the possible defect structure, high electron density of CdS and inhibition of electron/hole pairs as well as optimal content of CdS in the composite system. MnS/CdS composites must be evaluated for photocatalytic and photoelectrochemical activities with broader visible light range.

Effect of Metal Oxide–Support Interactions on Ethylene Oligomerization over Nickel Oxide/Silica–Alumina Catalysts

We investigated the interactions between nickel oxide and silica–alumina supports, which were applied to the catalytic oligomerization of ethylene by powder X-ray diffraction, UV diffuse reflectance spectroscopy, H2 temperature-programmed reduction, and X-ray photoelectron spectroscopy. The catalytic activity was also correlated with the acidity of catalysts determined by NH3 temperature-programmed desorption and pyridine FT-IR spectroscopy. Although all the catalysts had similar Ni contents, their catalytic performances were strongly influenced by the strength of the metal oxide–support interaction. Strong interaction promoted the formation of nickel aluminate on the catalyst surface, and resulted in low catalytic activity due to reducing the amount of nickel oxide active sites. However, weak interaction favored the aggregation of nickel oxide species into larger particles, and thus resulted in low ethylene conversion and selectivity to oligomers. Eventually, the optimal activity was realized at the medium interaction strength, preserving a high amount of both active nickel oxides and acid sites.

Ni0.9Mn0.1Fe2O4 nanoparticles preparation and sunlight-utilized photocatalytic activity

The metal hydrazine precursor of Ni0.9Mn0.1Fe2O4 nanoparticles was prepared through co-precipitation technique. Infrared spectrum of the precursor was showed the bridging bidentate nature of hydrazine. Multistep endothermic mass loss was observed from the thermogravimetric–differential thermogravimetric curves of the precursor. Ni0.9Mn0.1Fe2O4 nanoparticles synthesized from the precursor using thermal decomposition technique were characterized by infrared spectroscopy, energy-dispersive spectroscopy, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry and UV-diffuse reflectance spectroscopy which proposed the phase structure, morphology, magnetic and optical properties. An effective photocatalytic activity has shown by Ni0.9Mn0.1Fe2O4 nanoparticles on Congo red, malachite green, methylene blue, methyl red, rhodamine B and rose bengal under direct sunlight at different time intervals. The nanoparticles were magnetically separated and showed good recycling ability.

Solar active nano-Zn1−xMgxFe2O4 as a magnetically separable sustainable photocatalyst for degradation of sulfadiazine antibiotic

Fabricating magnetically recoverable solar-active photocatalysts with high performance capabilities for removal of recalcitrant and emerging pollutants has gained worldwide attention. Especially pharmaceutical pollutants as sulfonamides drugs which are now frequently detected in water systems are hard to remove because of their resistance to microbial and biological oxidation. This laboratory scale experiment presents synthesis of Mg substituted Zn nano-ferrite (Zn1-xMgxFe2O4) (x = 0, 0.2, 0.4) by facile modified sol-gel technique for sulfadiazine (SDZ) degradation. Effect of Mg doping on the zinc ferrite were investigated in this work which was analyzed by Transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and X-ray diffraction. The UV-diffuse reflectance spectroscopy studies reveal higher visible absorption extending to longer wavelengths. The VB of the ferrite catalyst shifts to 2.30 eV in substituted ferrite M2Z8 (x = 0.2) capable of hydroxyl radicals generation from H2O, which is difficult in parent ferrite without any Mg substitution. The electrochemical impedance spectroscopy and photo-current response analysis also reveal low impedance, higher charge flow and separation in case of M2Z8 catalyst which is reflected in the 99.1% SDZ degradation in 90 min with 73.2% total organic carbon removal in 120 min. Scavenging experiments confirm that hydroxyl radicals are main active species involved in degradation with Mg2+ and Fe3+ catalyzing the generation of hydroxyl radicals by undergoing redox process. LC-MS and TOC analysis confirm the drug mineralization. The work aims at fabricating solar active tunable photocatalysts for photo-degradation and mineralization of pharmaceutical pollutants using cost-effective approach.

A new catalyst material from electrospun PVDF-HFP nanofibers by using magnetron-sputter coating for the treatment of dye-polluted waters

In this study, polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP)–based nanofibers were produced by electrospinning technique on aluminum substrate and coated with magnetron sputtering technique by using Cu2O photocatalyst target material. Resulting materials were characterized by SEM, EDX, and UV diffuse reflectance spectroscopy. Photocatalytic activity of the material was tested against methylene blue decolorization under 105 W tungsten light bulb. Methylene blue concentration was followed up by UV visible spectrophotometer at 664 nm. Kinetic modeling of the photocatalytic reaction was found suitable to the first-order kinetics. Reaction rate constants were 0.0037, 0.0044, and 0.0050 min−1 respectively with corresponding half-life times of 187, 158, and 139 min. Thanks to the genuine design of the catalyst, it allowed easy removal of the material from the solution without any residue by simple tweezers which is a promising step for getting rid of heavy and low yield of filtration processes in the separation of particulate catalysts from the treated water.

An efficient and stable narrow bandgap carbon dot-brookite composite over other CD-TiO2 polymorphs in rhodamine B degradation under LED light

Carbon dot (CD) obtained from pine bark was loaded on three TiO2 polymorphs (anatase, rutile, and brookite abbreviated in this study as Ana, Rut, and Brk respectively) to evaluate their photocatalytic performance in rhodamine B (RhB) degradation under visible-LED light. The materials were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), x-ray powder diffraction (XRD), N2 sorption isotherm, and Fourier transform infrared (FT-IR), UV-diffused reflectance spectroscopy (UV-DRS), and x-ray photoelectron spectroscopy (XPS). The x-ray result shows that the different pure pristine polymorphs and their composites were successfully prepared with Rut and CD-Rut composite having the highest crystallite size of 23.06 and 21.64 nm respectively. The N2 sorption isotherm of the materials shows Ana, Brk and their composite exhibited type IV isotherm with H series hysteresis loop, which implies that they are mesoporous materials. The isotherm exhibited by Rut and CD-Rut suggests that they are non-porous. However, their pore size distribution (PSD) shows that the materials possess mesopores that may have resulted from interparticle voids due to particle aggregation. Results from the photocatalytic degradation experiments showed that the materials performed in the following order CD-Brk>Brk>CD-Ana>CD-Rut>Rut>Ana with a corresponding percentage RhB removal of 99.91, 76.78, 36.28, 27.50, 22.65, and 12% respectively. The excellent performance of CD-Brk and Brk over the others is attributed to their narrow bandgap energy of 2.00 eV making them more active under the visible-LED light. CD-Brk performed better than Brk because it possesses more surface-active sites resulting from its relatively higher surface area. In terms of degradation mechanism, CD-Brk which was stable after 4 cycles of degradation, showed that superoxide anion radical (O2•−) played major role in the degradation process.

Recoverability of Fe3O4/TiO2 nanocatalyst in methyl orange degradation

Iron oxide/titania (Fe3O4/TiO2) magnetic nanocatalysts approximately 30 nm in size were synthesized by co-precipitation method. The structure and morphology of the prepared nanocatalyst were characterized by Field Emission Scanning Electron Microscope coupled with Energy Dispersive X-ray spectroscopy (FESEM-EDX), Transmission Electron Microscope (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Raman Spectroscopy, UV Diffuse Reflectance Spectroscopy (UV-DRS), Vibrating Sample Magnetometer (VSM), and Brunauer–Emmett–Teller (BET) and Barrett-Joyner-Halenda (BJH) analyses. The prepared nanocatalyst showed good photocatalytic activity for the degradation of methyl orange (MO) dye solution. The Fe3O4/TiO2 (P25) showed better photocatalytic ability compared to that of Fe3O4/TiO2 (UV100) for MO dye degradation (10 ppm) under UV irradiation (λ = 254 nm). The experimental results revealed that 90.3% of MO dye was degraded with Fe3O4/TiO2 (P25) nanocatalyst, as compared to Fe3O4/TiO2 (UV100) nanocatalyst with only 51.6% after 1 h irradiation. The synthesized magnetic nanocatalysts are stable up to 5 cycles due to their strong recoverability towards an external magnet. Interestingly, the nanocatalyst was reasonably stable after being left undisturbed for 12 months.

Facile Synthesis of Ag3PO4 Photocatalyst with Varied Ammonia Concentration and Its Photocatalytic Activities For Dye Removal

The highly active photocatalyst of Ag3PO4 could be synthesized under ammonia solution using the facile co-precipitation method with the starting material of AgNO3 and Na2HPO4.12H2O. The variation of ammonia concentration was designed at 0.00, 0.05, 0.15, and 0.30 M. The products were characterized using X-ray diffraction, UV-diffuse reflectance spectroscopy, and scanning electron microscopy. The photocatalytic activities were evaluated using the Rhodamine B degradation under blue light irradiation. The effect of calcination, pH condition, and visible light source irradiation was carried out in the experiment. The highest photocatalytic activity was found in the sample prepared using the addition of ammonia solution at the concentration of 0.05 M. This photocatalytic activity was 4.13 times higher compared to the Ag3PO4 prepared without the ammonia. The effective condition of photocatalytic activity was achieved at the sample prepared without calcination, degradation at pH of 7 and under blue light irradiation.

Visible-light-driven g-C3N4/Cu2O heterostructures with efficient photocatalytic activities for tetracycline degradation and microbial inactivation

g-C3N4/Cu2O composites were successfully synthesized by a facile chemical precipitation method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and UV diffuse reflectance spectroscopy (UV-DRS) techniques were employed to characterize the as-synthesized photocatalysts. The photocatalytic experiments indicated that the g-C3N4/Cu2O composites displayed higher photodegradation activity of tetracycline (TC) and inactivation efficiencies of Escherichia coli (E. coli) as well as Fusarium graminearum (F. graminearum) in comparsion with bare g-C3N4 and Cu2O under visible light irradiation. Photoluminescence (PL) spectra implied that the heterojunction between g-C3N4 and Cu2O could efficiently promote the separation efficiency of photo-induced charge carriers. Active species trapping experiment and electron spin resonance (ESR) analysis revealed that O2−, OH and h+ played important roles in the photocatalytic process. This study could provide new insights into the design of multifunctional g-C3N4-based photocatalysts for environmental purification.

Photocatalytic Degradation of Reactive Dyes Over Titanates.

MTiO₃ (M = Sr, Ca, Ba and Pb) catalysts were synthesized by polymeric precursor method and characterized by using various instrumental techniques such as X-ray diffraction (XRD), UV-diffuse reflectance spectroscopy (UV-DRS), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). TiO₂ were also synthesized by sol-gel method and used for the optimization of reaction parameters such as catalyst weight, dye concentration and pH in the photocatalytic degradation of reactive dyes such as reactive blue 198 (RB 198), reactive black 5 (RB 5) and reactive yellow 145 (RY 145) under UV irradiation. MTiO₃ (M = Sr, Ca, Ba and Pb) catalysts were evaluated towards the photocatalytic decolourization of RB 198, RB 5 and RY 145 under optimized reaction conditions. Among the different metal titanates, strontium titanate showed the highest decolourization (≈90%) of all the three reactive dyes under UV irradiation at 120 minutes and also found to be active under visible irradiation as it decolourises the dyes in about 450 minutes. The degradation rate of strontium titanate was monitored by TOC analyzer. Kinetic studies of the photocatalytic degradation of reactive dyes confirmed that the reaction followed the pseudo first order kinetics.

HPW-Anchored UiO-66 Metal-Organic Framework: A Promising Photocatalyst Effective toward Tetracycline Hydrochloride Degradation and H2 Evolution via Z-Scheme Charge Dynamics.

The abolition of environmental pollutants and production of hydrogen (H2) from water using a heterogeneous photocatalyst is a demanding science of the current scenario to solve the increasing environmental pollution and worldwide energy catastrophe in modern life. To validate this purpose, the design of low-cost and durable semiconductor-based photocatalysts with great light absorption capacity becomes the most challenging issue for researchers. Regarding this, herein the phosphotungstic acid (HPW)-anchored Zr6O4(OH)4(BDC)6 (UiO-66) metal-organic framework (MOF), i.e., HPW@UiO-66, has been prepared by a hydrothermal method and is efficient, stable, and capable of harvesting solar energy toward the degradation of tetracycline hydrochloride (TCH) and H2 production in the presence of a sacrificial donor. The ionic interaction between HPW and UiO-66 plays a key role toward the photostability and charge-transfer mechanism of the composite and is well characterized with X-ray diffraction, UV diffuse-reflectance spectroscopy, Fourier transform infrared, and X-ray photoelectron spectroscopy. A total of 30 wt % HPW@UiO-66 shows a maximum degradation of about 87.24% of a 20 ppm TCH solution in 60 min of solar-light irradiation and about 353.89 μmol/h of H2 production. The conduction- and valence-band potentials are well characterized with Mott-Schottky measurement and a delay charge recombination process through electrochemical impedance spectroscopy. The proposed mediator-free Z-scheme-oriented electron-hole migration route is well supported by photoluminescence, and the scavenger test well explains the better charge-carrier separation and high catalytic performance of the prepared composite. This research will bestow an advantageous blueprint to fabricate novel and challenging photocatalysts toward the photocatalytic treatment of environmental pollutants and H2 evolution.

Preparation and study of ternary polypyrrole-tin oxide-chitin nanocomposites and their potential applications in visible light photocatalysis and sensors

In the present study, nanoparticles of tin oxide were synthesised by co-precipitation method along with polypyrrole-chitin matrix prepared by chemical oxidative polymerisation technique. The synthesized nanocomposites were characterized by Fourier transform–infra red spectroscopy (FT-IR), UV-diffuse reflectance spectroscopy (UV-DRS), X-ray diffraction (XRD) to determine the functional group, optical properties, crystallite size and geometry respectively. Moreover scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDAX) was used to study surface morphology and elemental composition of the sample. The synthesised nanocomposites shows enhanced photocatalytic activity towards RhB dyes under visible light with increasing tin oxide content. The holes and superoxide free radicals were found to be dominant species in photocatalysis confirmed by quenching experiment. The photocatalyst also shows better adsorption capability and recyclability, also the photodegradation favours the acidic medium. Furthermore, the electrocatalytic properties of the nanocomposites were also investigated by cyclic voltammetry for detection of methanol (0.001 M to 0.5 M) by drawing cyclic voltammogram in the range −1.0 to +1.0 V at scan rate of 10 mV/s. The nanocomposites as electrocatalyst showed better sensitivity even at lower concentration of 0.001 M. From the given data, it is evident that the synthesized nanocomposites can be used as effective photocatalyst as well as electrocatalyst in different areas.