Route to High Surface Area, Mesoporosity of Polyaniline–Titanium Dioxide Nanocomposites via One Pot Synthesis for Energy Storage Applications

This paper reports the synthesis of mesoporous polyaniline–titanium dioxide (Pani–TiO₂) nanocomposites via a one pot approach in the presence of aniline and titanium iso-propoxide precursor under ice bath conditions. Scanning and transmission electron microscopy showed that the Pani–TiO₂ was mesoporous in nature. BET analysis revealed the Pani–TiO₂ to have a 2-fold higher surface area than Pani. The shift of the peaks in the FTIR and XRD pattern showed that TiO₂ had perfectly intercalated into the Pani matrix, which suggests a strong interaction between Pani and TiO₂. The electrochemical properties of Pani and the mesoporous Pani–TiO₂ were examined by cyclic voltammetry and charge/discharge studies. The mesoporous Pani–TiO₂ electrode exhibited a high specific capacitance of 935 F g^–1 at 1 A g^–1 current density. The mesoporous Pani–TiO₂ displayed excellent cyclic stability up to 2000 cycles and delivered a high energy density of 94.8 Wh kg^–1 at a 977 W kg^–1 power density

Biogenic Synthesis, Photocatalytic, and Photoelectrochemical Performance of Ag–ZnO Nanocomposite

The development of coupled photoactive materials (metal/semiconductor) has resulted in significant advancements in heterogeneous visible light photocatalysis. This work reports the novel biogenic synthesis of visible light active <i>Ag</i>–ZnO nanocomposite for photocatalysis and photoelectrode using an electrochemically active biofilm (EAB). The results showed that the EAB functioned as a biogenic reducing tool for the reduction of Ag⁺, thereby eliminating the need for conventional reducing agents. The as-prepared <i>Ag</i>–ZnO nanocomposite was characterized by X-ray diffraction, transmission electron microscopy, diffuse reflectance spectroscopy, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy. The photocatalytic experiments showed that the <i>Ag</i>–ZnO nanocomposite possessed excellent visible light photocatalytic activity for the degradation of methyl orange, methylene blue, and 4-nitrophenol. Electrochemical impedance spectroscopy and linear scan voltammetry under dark and visible light irradiation confirmed the enhanced visible light activity of the <i>Ag</i>–ZnO as photocatalyst and photoelectrode. These results suggest that Ag nanoparticles induced visible light photocatalytic degradation and enhanced the visible light activity of the photoelectrodes by minimizing the recombination of photogenerated electrons and holes, thereby extending the response of pure ZnO to visible light

Enhanced Thermal Stability under DC Electrical Conductivity Retention and Visible Light Activity of Ag/TiO₂@Polyaniline Nanocomposite Film

The development of organic–inorganic photoactive materials has resulted in significant advancements in heterogeneous visible light photocatalysis. This paper reports the synthesis of visible light-active Ag/TiO₂@Pani nanocomposite film via a simple biogenic–chemical route. Electrically conducting Ag/TiO₂@Pani nanocomposites were prepared by incorporating Ag/TiO₂ in <i>N</i>-methyl-2-pyrrolidone solution of polyaniline (Pani), followed by the preparation of Ag/TiO₂@Pani nanocomposite film using solution casting technique. The synthesized Ag/TiO₂@Pani nanocomposite was confirmed by UV–visible spectroscopy, photoluminescence spectroscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The Ag/TiO₂@Pani nanocomposite film showed superior activity towards the photodegradation of methylene blue under visible light compared to Pani film, even after repeated use. Studies on the thermoelectrical behavior by DC electrical conductivity retention under cyclic aging techniques showed that the Ag/TiO₂@Pani nanocomposite film possessed a high combination of electrical conductivity and thermal stability. Because of its better thermoelectric performance and photodegradation properties, such materials might be a suitable advancement in the field of smart materials in near future

Biogenic Fabrication of Au@CeO₂ Nanocomposite with Enhanced Visible Light Activity

This study reports a biogenic approach to the synthesis of Au@CeO₂ nanocomposite using electrochemically active biofilms (EABs) in water under normal pressure and 30 °C. This work presents the results of extensive morphological, structural, optical, visible light photoelectrochemical and photocatalytic studies of Au@CeO₂ nanocomposite. The presence of a large number of interfaces between Au nanoparticles and CeO₂ for charge transfer is believed to play a key role in enhancing the optical and visible light photoelectrochemical and photocatalytic performance of Au@CeO₂ nanocomposite. The enhanced visible light degradation of methyl orange and methylene blue by Au@CeO₂ nanocomposite was much higher than that by pure CeO₂. The reusability, stability, and other results suggests that the Au@CeO₂ nanocomposite could be exploited as potential candidates for visible light photocatalysis, photovoltaic, and photoelectrochemical devices