Synthesis and Characterization of Hetero-metallic Oxides-Reduced Graphene Oxide Nanocomposites for Photocatalytic Applications

A new AgO.CuO.WO₃/rGO nanocomposite was designed for the investigation of the degradation ability of the hybrid material under visible light irradiation. The AgO, CuO, WO₃ NPs, and AgO.CuO.WO₃ hetero-metallic oxides were fabricated via the chemical co-precipitation method. The crystallite sizes and phase analyses were investigated by recording X-ray diffraction patterns. The crystallite sizes of three metal oxides in the AgO.CuO.WO₃ hetero metal oxide were 16.7, 15.9, and 16.9 nm, respectively. The FESEM images at various magnifications were probed to study the morphology of synthesized materials. The micrographs of hetero-metallic oxides AgO.CuO.WO₃ exposed that three metal oxides merged like small particles and gives a large bulbous appearance. EDX analyses confirmed the formation of required materials with high purity. FTIR data was in agreement with the literature which facilitated to ensure the purity of synthesized samples. The optical bandgap energy was calculated via the Tauc plot indicating that the blend of three metal oxides generated a new energy level in the electronic structure is suitable for photocatalysis in the presence of visible light. The bandgap energy of hetero metallic oxides was 1.25 eV which is less than individual metal oxides signifying the tuning of the bandgap. The incorporation of rGO in AgO.CuO.WO₃ hetero-metallic oxides gives a new photocatalyst for optimum photodegradation of methylene blue in minimum time. The percentage degradation via AgO.CuO.WO₃ was 87.20% in 70 min while the percentage degradation via AgO.CuO.WO₃/rGO recorded by photocatalytic experiment was 95% in 40 min. The photocatalysis data revealed that AgO.CuO.WO₃ hetero-metallic oxides-rGO nanocomposite ensured a strong potential to uptake organic dyes from water by promoting redox reactions during photocatalysis in the minimum time limit.     

CuxNi1-xO nanostructures and their nanocomposites with reduced graphene oxide: Synthesis,characterization, and photocatalytic applications

NiO nanostructure was synthesized using a simple co-precipitation method and was embedded on reduced graphene oxide surface via ultrasonication. Structural investigations were made through X-ray diffraction (XRD) and functional groups were confirmed by Fourier transform infrared spectroscopy (FTIR). XRD analysis revealed the grain size reduction with doping. Fourier transform infrared spectroscopy confirmed the presence of metal-oxygen bond in pristine and doped NiO nanostructure as well as the presence of carbon containing groups. Scanning electron microscopy (SEM) indicated that the particle size decreased when NiO nanostructure was doped with copper. BET surface area was found to increase almost up to 43 m²/g for Cu doped NiO nanostructure/rGO composite. Current-voltage measurements were performed using two probe method. UV–Visible spectroscopic profiles showed the blue and red shift for Cu doped NiO nanostructure and Cu doped NiO Nanostructure/rGO composite respectively. Rate constant for Cu doped NiO nanostructure/rGO composite found to increase 4.4 times than pristine NiO nanostructure.     

Exploring Regional Profile of Drought History- a New Procedure to Characterize and Evaluate Multi-Scaler Drought Indices Under Spatial Poisson Log-Normal Model

Water Resources Management - Drought is recurrently occurring in many parts of the globe. In contrast to other natural hazards, drought has complex climatic characteristics. Several environmental...     

Computer aided diagnosis of brain abnormalities using texture analysis of MRI images

The drive of this study is to develop a robust system. A method to classify brain magnetic resonance imaging (MRI) image into brain-related disease groups and tumor types has been proposed. The proposed method employed Gabor texture, statistical features, and support vector machine. Brain MRI images have been classified into normal, cerebrovascular, degenerative, inflammatory, and neoplastic. The proposed system has been trained on a complete dataset of Brain Atlas-Harvard Medical School. Further, to achieve robustness, a dataset developed locally has been used. Extraordinary results on different orientations, sequences of both of these datasets as per accuracy (up to 99.6%), sensitivity (up to 100%), specificity (up to 100%), precision (up to 100%), and AUC value (up to 1.0) have been achieved. The tumorous slices are further classified into primary or secondary tumor as well as their further types as glioma, sarcoma, meningioma, bronchogenic carcinoma, and adenocarcinoma, which could not be possible to determine without biopsy, otherwise.     

Fabrication of different conductive matrix supported binary metal oxides for supercapacitors applications

Here, we have fabricated the spinel binary-metal oxide (FeCo₂O₄) via a solvent-free and cost-effective approach. The nanocomposites of the as-fabricated binary-metal spinel oxide have been prepared with three different conductive-matrices, namely r-GO, CNTs, and PANI, via ultra-sonication approach. The spinel phase and surface functionalities of the fabricated FeCo₂O₄ sample have been confirmed via XRD and FT-IR analyses, respectively. The morphological-structure and elemental composition of the fabricated samples have been probed via FESEM and EDX results. The role of added conductive-matrices in the improvement of the electrical conductivities of the fabricated nanocomposites has been investigated via I–V experiments. The electrochemical experiments, conducted in half-cell configuration, showed that FeCo₂O₄/PANI nanocomposite exhibited the highest specific capacitance (658.9 Fg^-1) than that of the remaining two nanocomposites. Furthermore, FeCo₂O₄/PANI nanocomposite exhibited excellent cyclic stability as it lost just 8.3% of its initial specific capacitance even after 3000 cyclic tests. The superior capacitive-activity of the FeCo₂O₄/PANI nanocomposite is accredited to its high conductivity, large surface area, and synergy effects between the pseudocapacitance derived from the PANI and FeCo₂O₄ nanostructure. The electrochemical and electrical measurements suggested that FeCo₂O₄/PANI nanostructure is an emerging contender for energy storage applications.     

Amine-terminated aromatic and semi-aromatic hyperbranched polyamides: synthesis and characterization

A facile synthetic approach to aromatic and semiaromatic amine-terminated hyperbranched polyamides via direct polymerization of triamine (B₃) with different diacid chlorides (A₂) was explored. An aromatic triamine, 1,3,5-tris(4′-aminophenylcarbamoyl)benzene (TAPCB), was synthesized and monomers were characterized by elemental analysis, FTIR, ¹H and ¹³C NMR spectroscopy. Finally, the polycondensation reaction of TAPCB with terephthaloyl chloride (TPC), isophthaloyl chloride (IPC), sebacoyl chloride (SC) and adipoyl chloride (AC) resulted in the preparation of four hyperbranched polyamides i.e., HBPA 1, 2, 3 and 4, respectively. FTIR and ¹H NMR analyses confirmed the structures of the ensuing polymers and DB was found between 0.51–0.55. These thermally stable amorphous HBPAs were soluble in polar aprotic solvents at room temperature having glass transition temperatures (T_g) between 138–198 °C. Inherent viscosities (η_inh) and weight average molecular weights (M_w) were in the range of 0.27–0.35 dL/g and 1.3 × 10⁴–2.7 × 10⁴, respectively. Future prospects are envisaged.     

Exploring aramid as emerging contender for CO2 capture

To prevent CO_2 accumulation in the atmosphere generated from scorching of fossil fuels, carbon capture and sequestration(CCS) technology is considered as a potential route to mitigate the emissions of CO_2 from reaching the atmosphere. Power generation from sources such as gas, coal and biomass can fulfill the energy demand more readily than many other sources of electricity production. Thus these sources may be retained as important alternative option in the global energy cycle. In order to curtail CO_2, porous aramid network was fabricated by the condensation of 1,3,5-benzenetricarbonyl trichloride and 1,3-phenylenediamine in 1,4-dioxane solvent. Aramid was characterized for various analyses including FTIR, XRD, TGA, BET surface area and pore size analysis, FESEM and CO_2 adsorption measurements. Excellent thermal stability was provided by strong amide linkages in the polymer backbone. Optimum CO_2 uptake of aramid was achieved to be 23.14 mg·g~(-1) at 273 K at 0.1 MPa. The basic amide groups of network structure showed greater affinity for CO_2.Excellent thermal stability of aramid makes it a promising sorbent for CO_2 capture in adverse conditions.     

Water-Lubricated Ni-Based Composite(Ni-Al_2O_3,Ni-SiC and Ni-ZrO_2)Thin Film Coatings for Industrial Applications

In this work,pure nickel and Ni-based nanocomposite coatings(N1-Al_2O_3,Ni-SiC and Ni-ZrO_2) were produced on steel substrate by using pulse electrodeposition technique.The industrial performance tests were conducted to evaluate the wear resistance,corrosion resistance,adhesion strength and wettability behaviour of newly developed coatings.Rolling contact ball-on-disc tribometer was used to assess anti-wear behaviour of these coatings under waterlubricated contacts.The results showed that the wear- and corrosion resistance properties of nickel alumina and Ni-SiC composite coatings significantly improved than that of pure Ni and Ni-ZrO_2 coatings.The adhesion and wettability results of Ni-Al_2O_3 composite showed better performance when compared to the rest of the coatings.The effects of incorporating nanoparticles on the surface microstructure,interface adhesion and distribution of the particles were also investigated.The coatings were characterized by using scanning electron microscopy,X-ray diffraction analysis and 3D white light interferometry.The wear failure behaviour of these coatings was further examined by post-test surface observation under optical microscope.     

Nanostructure and mechanical properties of aromatic polyamide and reactive organoclay nanocomposites

Aromatic polyamide/organoclay nanocomposites were synthesized using the solution blending technique. Treatment of montmorillonite clay with p-phenylenediamine produced reactive organophilic clay for good compatibility with the matrix. Polyamide chains were prepared by condensing a mixture of 1,4-phenylenediamine and 4-4′-oxydianiline with isophthaloyl chloride under anhydrous conditions. These chains were end capped with carbonyl chloride using 1% extra acid chloride near the end of reaction to develop the interactions with organoclay. The dispersion and structure–property relationship were monitored using FTIR, XRD, FE-SEM, TEM, DSC and tensile testing of the thin films. The structural investigations confirmed the formation of delaminated and disordered intercalated morphology with nanoclay loadings. This morphology of the nanocomposites resulted in their enhanced mechanical properties. The tensile behavior and glass transition temperature significantly augmented with increasing organoclay content showing a greater interaction between the two disparate phases.     

Hydrothermal synthesis of multiwalled TiO2 nanotubes and its photocatalytic activities for Orange II removal

The solvothermal synthesis of multiwalled TiO₂ nanotubes (MWTNTs) with the reaction of titanium dioxide (TiO₂) nanoparticles and sodium hydroxide aqueous solution at moderate temperature is presented. The kinetic and isotherm studies were investigated for Orange II removal mechanism. MWTNTs were prepared in length 70–200 nm, average diameter 4–10 nm, and inter-shell spacing 0.78 nm. Different characterizations were performed to confirm anatase and mesoporous structure of MWTNTs. An improvement in properties as compared to commercial TiO₂ was observed; specific surface area 244.81 m²/g and band gap 3.0 eV. An excellent photocatalytic activity for Orange II removal was exhibited using synthesized MWTNTs.