Elements Of X Ray Diffraction

Flexible solid-state supercapacitors (FSSCs) are frontrunners in energy storage device technology and have attracted extensive attention owing to recent significant breakthroughs in modern wearable electronics In this study, we review the state-of-the-art advancements in FSSCs to provide new insights on mechanisms, emerging electrode materials, flexible gel electrolytes and novel cell designs The review begins with a brief introduction on the fundamental understanding of charge storage mechanisms based on the structural properties of electrode materials The next sections briefly summarise the latest progress in flexible electrodes (ie, freestanding and substrate-supported, including textile, paper, metal foil/wire and polymer-based substrates) and flexible gel electrolytes (ie, aqueous, organic, ionic liquids and redox-active gels) Subsequently, a comprehensive summary of FSSC cell designs introduces some emerging electrode materials, including MXenes, metal nitrides, metal–organic frameworks (MOFs), polyoxometalates (POMs) and black phosphorus Some potential practical applications, such as the development of piezoelectric, photo-, shape-memory, self-healing, electrochromic and integrated sensor-supercapacitors are also discussed The final section highlights current challenges and future perspectives on research in this thriving field

Towards flexible solid-state supercapacitors for smart and wearable electronics

Heterogeneous photocatalysis that employs photo-excited semiconductor materials to reduce water and oxidize toxic pollutants upon solar light irradiation holds great prospects for renewable energy substitutes and environmental protection. To utilize solar light effectively, the quest for highly active photocatalysts working under visible light has always been the research focus. Layered BiOX (X = Cl, Br, I) are a kind of newly exploited efficient photocatalysts, and their light response can be tuned from UV to visible light range. The properties of semiconductors are dependent on their morphologies and compositions as well as structures, and this also offers the guidelines for design of highly-efficient photocatalysts. In this review, recent advances and emerging strategies in tailoring BiOX (X = Cl, Br, I) nanostructures to boost their photocatalytic properties are surveyed.

Engineering BiOX (X = Cl, Br, I) nanostructures for highly efficient photocatalytic applications

Nanostructures have attracted huge interest as a rapidly growing class of materials for many applications. Several techniques have been used to characterize the size, crystal structure, elemental composition and a variety of other physical properties of nanoparticles. In several cases, there are physical properties that can be evaluated by more than one technique. Different strengths and limitations of each technique complicate the choice of the most suitable method, while often a combinatorial characterization approach is needed. In addition, given that the significance of nanoparticles in basic research and applications is constantly increasing, it is necessary that researchers from separate fields overcome the challenges in the reproducible and reliable characterization of nanomaterials, after their synthesis and further process (e.g. annealing) stages. The principal objective of this review is to summarize the present knowledge on the use, advances, advantages and weaknesses of a large number of experimental techniques that are available for the characterization of nanoparticles. Different characterization techniques are classified according to the concept/group of the technique used, the information they can provide, or the materials that they are destined for. We describe the main characteristics of the techniques and their operation principles and we give various examples of their use, presenting them in a comparative mode, when possible, in relation to the property studied in each case.

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Characterization techniques for nanoparticles: comparison and complementarity upon studying nanoparticle properties

The great success of electrochemiluminescence (ECL) for in vitro diagnosis (IVD) and its promising potential in light-emitting devices greatly promote recent ECL studies. More than 45% of ECL articles were published after 2010, and the first international meeting on ECL was held in Italy in 2014. This critical review discusses recent vibrant developments in ECL, and highlights novel ECL phenomena, such as wireless ECL devices, bipolar electrode-based ECL, light-emitting electrochemical swimmers, upconversion ECL, ECL resonance energy transfer, thermoresponsive ECL, ECL using shape-controlled nanocrystals, and ECL as an ion-selective electrode photonic reporter, a paper-based microchip, and a self-powered microfluidic ECL platform. We also comment on the latest progress in bioassays, light-emitting devices and, the computational approach for the ECL mechanism study. Finally, perspectives and key challenges in the near future are addressed (198 references).

Recent advances in electrochemiluminescence

A simple solvothermal route was explored to prepare hierarchical, nanostructured flower-like bismuth oxychlorides (BiOCl) by employing pyridine as the solvent. The volume ratios of distilled water to pyridine play an important role in the assembly of the BiOCl nanostructure from nanoplates to nanoflowers. The as-prepared BiOCl nanoflowers were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, and nitrogen sorption. The resulting BiOCl nanoflowers with high specific surface area were phase-pure and self-assembled from thin nanoplates during the reaction process. In addition, the photocatalytic properties of the as-prepared samples were further investigated by photocatalytic decomposition of methyl orange (MO) dye, and it was found that the BiOCl nanoflowers showed a higher photocatalytic activity than that of TiO2 (Degussa, P25) under modeling sunlight.

Hierarchical structured bismuth oxychlorides: self-assembly from nanoplates to nanoflowers via a solvothermal route and their photocatalytic properties

Controlled synthesis of nickel sulfide/graphene oxide nanocomposite for high-performance supercapacitor

ZnFe2O4 nanoparticles with diameter of ca.10 nm were successfully synthesized under hydrothermal conditions without using any surfactant or structure-directing agents. The structure, composition and morphology of the samples were characterized by means of powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectra (DRS) and the Brunauer–Emmett–Teller (BET) surface area measurement. The results showed that the mole ratio of reactants ZnO to FeCl3 played an important role in controlling the composition and morphology of the products. BET specific surface area of ZnFe2O4 nanoparticles was evaluated to be 115.6 m2 g−1. Interestingly, as-prepared ZnFe2O4 nanoparticles displayed enhanced gas sensing performance to acetone, which response value reached 39.5 for 200 ppm acetone gas at lower optimum working temperature of 200 °C, in comparison with the precursor ZnO (4.2) at the same condition. The gas sensing property demonstrates that as-prepared ZnFe2O4 has potential applications in the detection of acetone.

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ZnFe2O4 nanoparticles: Synthesis, characterization, and enhanced gas sensing property for acetone

Enhanced electrochemiluminescence of CdSe quantum dots composited with graphene oxide and chitosan for sensitive sensor.

A novel electrochemiluminescence biosensor for the detection of microRNAs based on a DNA functionalized nitrogen doped carbon quantum dots as signal enhancers

Chang-Jie Mao

Papers

Hierarchical structured bismuth oxychlorides: self-assembly from nanoplates to nanoflowers via a solvothermal route and their photocatalytic properties

Controlled synthesis of nickel sulfide/graphene oxide nanocomposite for high-performance supercapacitor

ZnFe2O4 nanoparticles: Synthesis, characterization, and enhanced gas sensing property for acetone

Enhanced electrochemiluminescence of CdSe quantum dots composited with graphene oxide and chitosan for sensitive sensor.

A novel electrochemiluminescence biosensor for the detection of microRNAs based on a DNA functionalized nitrogen doped carbon quantum dots as signal enhancers