Sonication-supported synthesis of cobalt oxide assembled on an N-MWCNT composite for electrochemical supercapacitors via three-electrode configuration.

The Co3O4@N-MWCNT composite was synthesized by a sonication-supported thermal reduction process for supercapacitor applications. The structural and morphological properties of the materials were characterized via Raman, XRD, XPS, SEM-EDX, and FE-TEM analysis. The composite electrode was constructed into a three-electrode configuration and examined by using CV, GCD and EIS analysis. The demonstrated electrochemical value of ~ 225 F/g at 0.5 A/g by the electrode made it appropriate for potential use in supercapacitor applications.

MOFs-Graphene Composites Synthesis and Application for Electrochemical Supercapacitor: A Review.

Today's world requires high-performance energy storage devices such as hybrid supercapacitors (HSc), which play an important role in the modern electronic market because supercapacitors (Sc) show better electrical properties for electronics devices. In the last few years, the scientific community has focused on the coupling of Sc and battery-type materials to improve energy and power density. Recently, various hybrid electrode materials have been reported in the literature; out of these, coordination polymers such as metal-organic frameworks (MOFs) are highly porous, stable, and widely explored for various applications. The poor conductivity of classical MOFs restricts their applications. The composite of MOFs with highly porous graphene (G), graphene oxide (GO), or reduced graphene oxide (rGO) nanomaterials is a promising strategy in the field of electrochemical applications. In this review, we have discussed the strategy, device structure, and function of the MOFs/G, MOFs/GO, and MOFs/rGO nanocomposites on Sc. The structural, morphological, and electrochemical performance of coordination polymers composites towards Sc application has been discussed. The reported results indicate the considerable improvement in the structural, surface morphological, and electrochemical performance of the Sc due to their positive synergistic effect. Finally, we focused on the recent development in preparation methods optimization, and the opportunities for MOFs/G based nanomaterials as electrode materials for energy storage applications have been discussed in detail.

Impact of Annealing Temperature on the Morphological, Optical and Photoelectrochemical Properties of Cauliflower-like CdSe0.6Te0.4 Photoelectrodes; Enhanced Solar Cell Performance.

We are reporting on the impact of air annealing temperatures on the physicochemical properties of electrochemically synthesized cadmium selenium telluride (CdSe0.6Te0.4) samples for their application in a photoelectrochemical (PEC) solar cell. The CdSe0.6Te0.4 samples were characterized with several sophisticated techniques to understand their characteristic properties. The XRD results presented the pure phase formation of the ternary CdSe0.6Te0.4 nanocompound with a hexagonal crystal structure, indicating that the annealing temperature influences the XRD peak intensity. The XPS study confirmed the existence of Cd, Se, and Te elements, indicating the formation of ternary CdSe0.6Te0.4 compounds. The FE-SEM results showed that the morphological engineering of the CdSe0.6Te0.4 samples can be achieved simply by changing the annealing temperatures from 300 to 400 °C with intervals of 50 °C. The efficiencies (ƞ) of the CdSe0.6Te0.4 photoelectrodes were found to be 2.0% for the non-annealed and 3.1, 3.6, and 2.5% for the annealed at 300, 350, and 400 °C, respectively. Most interestingly, the PEC cell analysis indicated that the annealing temperatures played an important role in boosting the performance of the photoelectrochemical properties of the solar cells.

Cellulose Nanofiber Composite with Bimetallic Zeolite Imidazole Framework for Electrochemical Supercapacitors.

Cellulose nanofiber (CNF) and hybrid zeolite imidazole framework (HZ) are an emerging biomaterial and a porous carbonous material, respectively. The composite of these two materials could have versatile physiochemical characteristics. A cellulose nanofiber and cobalt-containing zeolite framework-based composite was prepared using an in-situ and eco-friendly chemical method followed by pyrolysis. The composite was comprised of cobalt nanoparticles decorated on highly graphitized N-doped nanoporous carbons (NPC) wrapped with carbon nanotubes (CNTs) produced from the direct carbonization of HZ. By varying the ratio of CNF in the composite, we determined the optimal concentration and characterized the derived samples using sophisticated techniques. Scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS) confirmed the functionalization of CNF in the metallic cobalt-covered N-doped NPC wrapped with CNTs. The CNF-HZNPC composite electrodes show superior electrochemical performance, which is suitable for supercapacitor applications; its specific capacitance is 146 F/g at 1 A/g. Furthermore, the composite electrodes retain a cycling stability of about 90% over 2000 charge-discharge cycles at 10 A/g. The superior electrochemical properties of the cellulose make it a promising candidate for developing electrodes for energy storage applications.

Nickel-Graphene Nanoplatelet Deposited on Carbon Fiber as Binder-Free Electrode for Electrochemical Supercapacitor Application.

A binder-free process for the electrode preparation for supercapacitor application was suggested by drop casting graphene nanoplatelets on a carbon fiber (GnP@CF) followed by electrodeposition of Ni nanoparticles (NPs). The microstructure of the electrode showed that Ni was homogeneously distributed over the surface of the GnP@CF. XRD analysis confirmed the cubic structure of metallic Ni NPs. The Ni-GnP@CF electrode showed excellent pseudocapacitive behavior in alkaline solution by exhibiting a specific capacitance of 480 F/g at 1.0 A/g, while it was 375 F/g for Ni@CF. The low value of series resistance of Ni-GnP@CF (1 Ω) was attributed to the high capacitance. The enhanced capacitance of the electrode could be correlated to the highly nanoporous structure of the composite material, synergetic effect of the electrical double layer charge-storage properties of graphene, and the pseudocapacitive nature of Ni NPs.

Ultrasonically driven green synthesis of palladium nanoparticles by Coleus amboinicus for catalytic reduction and Suzuki-Miyaura reaction.

A novel ultrasonically driven bio-reduction method was adopted to reduce the palladium chloride into palladium nanoparticles (PdNPs@CA) using coleus amboinicus extract as a green synthetic protocol. XRD confirms the formation of phase pure cubic Pd nanoparticles with the crystallite size range of 40-50 nm. The UV-vis spectrum reveals the formation of Pd nanoparticles by the disappeared peak at 480 nm of PdCl2 solution. The size distribution and surface morphology of prepared Pd nanoparticles showed spherical shaped nanoparticles with less agglomeration. The catalytic reduction behaviour of the Pd suspension is studied by 4-nitro phenol reduction process in 8 min further confirms its high catalytic performance. Synthesized PdNPs@CA were explored in ultrasound promoted Suzuki-Miyaura coupling reaction to determine the catalytic behaviour with ultrasonic frequency of 40 kHz and power of 150 W (Power sonic 410 bath sonicator) and its recycling ability is determined. It was found that aryl halides reacted with aryl boronic acids to obtain biaryl compound with excellent reaction yields in the presence of PdNPs@CA only in 30 min using PEG-400 as a green solvent. PdNPs@CA can be recovered efficiently and reused for 7 cycles without loss of its catalytic property.

Silica nano supra-assembly for the targeted delivery of therapeutic cargo to overcome chemoresistance in cancer.

Cancer cells become resistant over the period to chemotherapeutic drugs and pose a challenging impediment for oncologists in providing effective treatment. Nanomedicine allows to overcome chemoresistance and is the focus of our investigation. Silica nanostructures have been highlighted as an interesting drug delivery platform in vitro and in vivo applications. Here we show the validity of nanomedicine approach for targeted chemotherapeutic cargo delivery to overcome chemoresistance in cancer cells both in vitro and in vivo. For demonstrating the concept, we functionalised ∼100 nm long porous silica nanoparticles (∼20 nm diameter ordered pore structure) by conjugating anticancer drug, cytochrome c enzyme and dual-function anticancer aptamer AS1411 in single supra-assembled nanocargos. The supra-assembly on the porous silica nanostructure allows for a high loading of catalytic enzyme cytochrome c, anticancer drug and aptamer. The silica supra-assembly is characterized by transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) surface area analysis. Conjugation of cargoes has been monitored at each step by UV-vis and Fluorescence spectroscopy. Finally, the constructed supra-assembled nanocarrier tested on chemoresistance colon cancer (HCT116) cells. A pH-responsive, intracellular theranostic cargo delivery has been achieved and the triple action of the nanocargo made an efficient killing of drug resistance colon cancer cells in vitro (∼ 92% cell death) through triplex therapy effects by supressing the P-glycoprotein (P-gp) level. Furthermore, in vivo animal toxicity studies demonstrated, the supra-assembled nanocargos have encouraging safety index to be used in cancer therapy and drug delivery applications.

Stable Triple-Cation (Cs+-MA+-FA+) Perovskite Powder Formation under Ambient Conditions for Hysteresis-Free High-Efficiency Solar Cells.

Organometallic halide perovskite materials have promising photovoltaic properties and emerged as a cost-effective solar cell technology. However, a synthesis protocol to fabricate high-quality perovskite thin films under ambient conditions remains a critical issue and hinders commercialization of the technology. Therefore, this paper proposes efficient and stable fabrication of triple-cation perovskite photoactive solid-state thin film for solar cells using preformed perovskite powder under ambient conditions. Highly crystalline triple-cation perovskite powder was synthesized by a solution-processed antisolvent recrystallization technique, and films were prepared following a previously reported recipe for an efficient triple-cation perovskite. The synthesized perovskite powder was characterized using UV-visible absorption spectroscopy, X-ray diffraction, time-resolved photoluminescence, and field emission scanning electron microscopy. Fabricated solar cells were investigated for photovoltaic characteristics, including current density-voltage hysteresis, recombination losses, and thermal stability. The improved photovoltaic characteristics and thermal stability were attributed to the superior perovskite film quality and crystalline properties.

Ni(OH)2-decorated nitrogen doped MWCNT nanosheets as an efficient electrode for high performance supercapacitors.

In this study, nickel hydroxide nanoparticles (NPs) decorated with nitrogen doped multiwalled carbon nanotubes (N-MWCNT) hybrid composite was synthesized by thermal reduction process in the presence of cetyl ammonium bromide (CTAB) and urea. The as-synthesized Ni(OH)2@N-MWCNT hybrid composite was characterized by FTIR, Raman, XRD, BET, BJH and FE-TEM analyses. These prepared porous carbon hybrid composite materials possessed high specific surface area and sheet like morphology useful for active electrode materials. The maximum specific capacitance of Ni(OH)2@N-MWCNT hybrid nanocomposite in the two electrode system showed 350 Fg-1 at 0.5 A/g,energy density ~43.75 Wkg-1 and corresponds to power density 1500 W kg-1 with excellent capacity retention after 5000 cycles. The results suggest that the prepared two-dimensional hybrid composite is a promising electrode material for electrochemical energy storage applications.

Facile Synthesis of Triphenylamine Based Hyperbranched Polymer for Organic Field Effect Transistors.

In this study, we reported the synthesis and characterization of a novel hyperbranched polymer (HBPs) tris[(4-phenyl)amino-alt-4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene] (PTPABDT) composed of benzo[1,2-b:4,5-b']dithiophene (BDT) and triphenyleamine (TPA) constituent subunits by A3 + B2 type Stille's reaction. An estimated optical band gap of 1.69 eV with HOMO and LUMO levels of -5.29 eV and -3.60 eV, respectively, as well as a high thermal stability up to 398 °C were characterized for the synthesized polymer. PTPABDT fabricated as an encapsulated top gate/bottom contact (TGBC), organic field effect transistors (OFET) exhibited a p-type behavior with maximum field-effect mobility (µmax) and an on/off ratio of 1.22 × 10-3 cm2 V-1 s-1 and 7.47 × 102, respectively.

Visible Light Photocatalytic Performance of In Situ Synthesized Graphite-SiO2-TiO2 Composite Towards Degradation of Benzene Gas.

Graphite-SiO2-TiO2 composites with optimum graphite and SiO2 loadings were prepared by a facile one-pot chemical route. The structural, morphological and physiochemical properties of the samples were investigated by analytical techniques. UV-Vis-DRS analysis confirmed light absorbance edge of composites was sharply red-shifted to the visible region with increasing graphite and SiO2 content. The prepared composites showed higher photocatalytic activity towards degradation of benzene gas under visible light. The contribution of graphite and SiO2 on the enchantment of visible light photocatalytic performance of the composites was discussed.

Functional TiO2 nanocoral architecture for light-activated cancer chemotherapy.

To achieve light-triggered drug release in cancer chemotherapy, we developed multimodal titanium dioxide (TiO2) nanocorals modified with methoxy polyethylene glycol (mPEG). TiO2 nanocoral-like structures were synthesized by optimizing a solvothermal method. The developed nanocoral structures were efficiently conjugated with chemotherapeutic drugs on the surfaces of the TiO2 nanoparticles. The mPEG on the surfaces of the multifunctional nanocorals effectively conjugated the drug and improved the biocompatibility of the nanocorals. Following UV light irradiation, the TiO2 nanocorals produce free radicals (˙OH and ˙O2 -) and are effective for drug release in cancer cells. Importantly, the amount of drug released from the multimodal TiO2 nanocorals can be regulated by UV-light irradiation time, which allows for further control of the anti-cancer effect. The multimodal TiO2 nanocorals exhibit a combination of light-activated, stimuli-triggered drug release for killing of cancer cell. The cytotoxicity, cellular uptake, and intracellular location of the formulations were evaluated in MCF7 cells. Our results showed that nanocoral-DOX complexes exhibited a greater cytotoxicity toward MCF7 cells than free DOX. Our work demonstrates that the therapeutic efficacy of DOX-loaded TiO2 nanocorals is strongly dependent on their loading mode and the chemotherapeutic effect is improved under UV light illumination, which provides a significant breakthrough for future applications of TiO2 as a light activated drug carrier in cancer chemotherapy.

Enhanced photocatalytic inactivation of bacteria on Fe-containing TiO2 nanoparticles under fluorescent light.

In this paper, the photocatalytic activity of Fe-TiO2 nanoparticles (NPs) under fluorescent light was studied using Escherichia coli and Staphylococcus aureus. Fe-TiO2 NPs were synthesized using a sol-gel method and characterized with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (UV-vis DRS) and transmission electron microscopy. The efficiency of photocatalytic inactivation towards E. coli was studied under different physicochemical parameters. The photocatalytic inactivation rate increased with increasing Fe content in TiO2 NPs and the highest inactivation was achieved for 3.0 mol% Fe-TiO2 NPs under fluorescent light. These results demonstrate that the presence of an optimum concentration of Fe in TiO2 matrix enhances the photocatalytic inactivation of TiO2 NPs under fluorescent light.