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Polyaniline (PAni)–coated ZnO–SiO2–based hybrid material was prepared successfully with the in-situ polymerisation method and the product was subsequently analysed using XPS, XRD, TEM, UV-vis, TGA, FTIR and BET. The optical band gap calculated from the Tauc plot was found to be 2.89 eV. Moreover, this work reports an extensive study of the effect of the SiO2 on the electrochemical performance of hybrid material based on ZnO and PAni employing cyclic voltammetry. Furthermore, to evaluate the adsorption of methylene blue (MB), the parameters for the effectiveness of the adsorption process, including pH value, concentration and temperature, were investigated. The results indicated that the maximum adsorption of MB on the produced hybrid material occurred at pH 6.8 with a capacity reaching 71.2 mg.g−1. The thermodynamic studies indicate that the adsorption of MB on this adsorbent is spontaneous and endothermic in nature. Furthermore, PAni@ZnO–SiO2 is attractive for treating the effluents containing dyes due to its recyclability and high removal capacity. [ABSTRACT FROM AUTHOR]

In this research, we are interested to study the physical properties of the double perovskite oxide Ba2GdNbO6 under the effect of octahedral tilting, where this material crystallises in the tetragonal structure (I4/m (no. 87), Z = 2). The structural, electronic and magnetic properties are investigated using the spin-polarised density functional theory within the framework of the GGA + U approximation. The structural stability for Ba2GdNbO6 compound has been verified; this shows that I4/m structure is reported as stable ground state of Ba2GdNbO6 compound. The phenomenon of octahedral tilting contributes to the stability of this material and to the apparition of the quantum aspect. The X-spectra study show that the structural transition can occur between the I4/m symmetry system (the stable ground state) and the Fm 3 ¯ m symmetry system (the excited state), the absorbed radiation of this structural transition corresponds to the Middle-Wave-Infrared (MWIR). The electronic structure of Ba2GdNbO6 compound has been investigated in the stable ground state; the results show that the octahedral Ba2GdNbO6 compound has semiconductor behaviour with an indirect band gap. The results of total and partial spin-magnetic moments of Ba2GdNbO6 compound show that the main contribution to the total magnetic moment comes from the Gd ion, it is obvious to note that the half-filled in Gd (4f7) orbital is responsible for the semiconductor behaviour. Moreover, the GGA + U approximation supported by QTL programme shows that the multiplicity in the occupied 4f-Gd states is corresponding to the lower energy level of (8 S ( 7 2 ) ↑ ). [ABSTRACT FROM AUTHOR]

This research reports the facile, controlled, low-cost fabrication, and evaluation of properties of polyaniline matrix deposited on titanium dioxide and copper(II) oxide ternary-composite (PANI@TiO2–CuO)-based electrode material for supercapacitor application. The process involves the preparation of CuO in the presence of TiO2 to form TiO2–CuO by a facile method, followed by in-situ oxidative polymerization of aniline monomer. The structural and physical properties were evaluated based on the results of FTIR spectroscopy, X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), transmission electron (TEM) and scanning electron (SEM) microscopy, thermogravimetric analysis (TGA), and BET surface areas analysis. The results indicated that TiO2–CuO was dispersed uniformly in the PANI matrix. Owing to such dispersion of TiO2–CuO, the PANI@TiO2–CuO material exhibits dramatic improvements on thermal stability in comparison with the pure PANI. The cyclic voltammetry (CV) confirms the reversibility of PANI redox transitions for this optimized electrode material. Moreover, the results reveal that the specific capacitance of PANI@TiO2–CuO reaches 87.5% retention after 1500 cycles under 1.0 A g−1, with a better charge storage performance as compared to pure PANI and PANI@TiO2 electrodes. The preparation of PANI@TiO2–CuO with enhanced electrochemical properties provides a feasible route for promoting its applications in supercapacitors. [ABSTRACT FROM AUTHOR]