Special Libraries, January 1925

Volume 16, Issue 1https://scholarworks.sjsu.edu/sla_sl_1925/1000/thumbnail.jp

Conjugated carbon nitride as an emerging luminescent material: Quantum dots, thin films and their applications in imaging, sensing, optoelectronic devices and photoelectrochemistry

Over the past few years, graphitic/polymeric carbon nitride (CN) has attracted widespread attention due to its interesting electronic properties, which have been exploited in various applications, including, for example, in photo‐ and electrocatalysis, heterogeneous catalysis, CO2 reduction and water splitting. Its unique and tunable optical, chemical, and catalytic properties, alongside its low price and remarkably high stability to oxidation and harsh chemical environments, make it a very attractive material for optoelectronic devices as well as imaging and sensing‐related applications. In this Minireview, we will focus on the optical and photophysical properties of CN films and quantum dots and their potential applications in sensors, LEDs, solar cells and other photoelectronic devices. The synthetic approaches which determine the final chemical and photophysical properties of the CN materials are thoroughly elaborated

The performance of nanoparticulate graphitic carbon nitride as an amphiphile

Graphitic carbon nitride (g-C3N4), a polymeric semiconductor that finds potential applications in multiple areas, is shown to feature amphiphilic behavior. Since the feasibility of g-C3N4 aqueous colloids is well-established, g-C3N4 can be viewed as an effective and well-accessible colloidal amphiphile. Its activity at different interfaces (liquid–liquid, liquid–solid, and liquid–air) is illustrated: g-C3N4 is able to stabilize Pickering emulsions formed by water and organic solvents, and also, gas-filled g-C3N4 frameworks based on those emulsions are obtained by natural drying. Hydrophobic solid substances like graphite and carbon nanotubes are smoothly dispersed in water assisted by g-C3N4. Besides, networklike g-C3N4 membranes floating on a water surface are created and can be readily transferred to substrates. These findings provide many opportunities for the processing of g-C3N4-containing functional materials and devices

Electrophoretic deposition of carbon nitride layers for photoelectrochemical applications

Electrophoretic deposition (EPD) is used for the growth of carbon nitride (C₃N₄) layers on conductive substrates. EPD is fast, environmentally friendly, and allows the deposition of negatively charged C₃N₄ with different compositions and chemical properties. In this method, C₃N₄ can be deposited on various conductive substrates ranging from conductive glass and carbon paper to nickel foam possessing complex 3D geometries. The high flexibility of this approach enables us to readily tune the photophysical and photoelectronic properties of the C₃N₄ electrodes. The advantage of this method was further illustrated by the tailored construction of a heterostructure between two complementary C₃N₄, with marked photoelectrochemical activity

Microwave-assisted ionic liquid solvothermal rapid synthesis of hollow microspheres of alkaline earth metal fluorides (MF2, M = Mg, Ca, Sr)

A microwave-assisted ionic liquid solvothermal method is demonstrated to synthesize CaF2 double-shelled hollow microspheres. This method is simple and time-saving and can also be extended to prepare hollow microspheres of MgF2 and SrF2

Y4Al2O9 hierarchically nanostructured microspheres assembled with nanosheets: Microwave-solvothermal synthesis combined with thermal treatment and photocatalytic property

We have developed a microwave-solvothermal synthesis combined with thermal treatment method for the preparation of Y4Al2O9 hierarchically nanostructured microspheres assembled with nanosheets. First, a simple microwave-assisted solvothermal method is used to prepare the precursor using Y(NO3)3 and Al(NO3)3 at 200 °C in mixed solvents of water and N,N-dimethylformamide (DMF) without any surfactant. Then, thermal treatment of the precursor at 900 °C in air for 2 h is performed to obtain Y4Al2O9 hierarchically nanostructured microspheres, during which the morphology of the precursor can be well preserved. The samples are characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The photocatalytic activity of as-prepared Y4Al2O9 hierarchical microspheres over phenol is investigated and the degradation rate of phenol is up to 91.2% in a period of 240 min.<!-- /react-text --

Colorful Silver/Carbon Nitride Composites Obtained by Photoreduction

The Ag+ photoreduction by graphitic carbon nitride(g-CN) materials in a high concentration of Ag+ solution is reported, and a series of colorful Ag/g-CN composites is prepared and characterized. The chromatic change correlates to the carbon nitride materials synthesized at different heating temperatures(CNT, where T means heating temperature), taking advantage of the different photocatalytic activities of different CNT. The mechanism beneath this phenomenon is attributed to two factors: the particle size of Ag NPs and the coordinate effect of Ag NPs on CNT sheets. Interestingly, the multicolors of Ag/g-CN composites display only on the CNT materials synthesized from heating melamine-cyanuric acid precursor, but not on the CNT from heating pure melamine. The color of the as-prepared Ag/g-CN composites can endure the corrosion of HNO3 and ethanol, which shows a good chemical stability and may hint its application as chromophores.</p

y-Fe2O3 and Fe3O4 magnetic hierarchically nanostructured hollow microspheres: Preparation, formation mechanism, magnetic property, and application in water treatment

In this paper, we report the preparation of γ-Fe2O3 and Fe3O4 magnetic hierarchically nanostructured hollow microspheres by a solvothermal combined with precursor thermal conversion method. These γ-Fe2O3 and Fe3O4 magnetic hierarchically nanostructured hollow microspheres were constructed by three-dimensional self-assembly of nanosheets, forming porous nanostructures. The effects of experimental parameters including molar ratio of reactants and reaction temperature on the precursors were studied. The time-dependent experiments indicated that the Ostwald ripening was responsible for the formation of the hierarchically nanostructured hollow microspheres of the precursors. γ-Fe2O3 and Fe3O4 magnetic hierarchically nanostructured hollow microspheres were obtained by the thermal transformation of the precursor hollow microspheres. Both γ-Fe2O3 and Fe3O4 hierarchically nanostructured hollow microspheres exhibited a superparamagnetic property at room temperature and had the saturation magnetization of 44.2 and 55.4 emu/g, respectively, in the applied magnetic field of 20 KOe. Several kinds of organic pollutants including salicylic acid (SA), methylene blue (MB), and basic fuchsin (BF) were chosen as the model water pollutants to evaluate the removal abilities of γ-Fe2O3 and Fe3O4 magnetic hierarchically nanostructured hollow microspheres. It was found that γ-Fe2O3 hierarchically nanostructured hollow microspheres showed a better adsorption ability over SA than MB and BF. However, Fe3O4 hierarchically nanostructured hollow microspheres had the best performance for adsorbing MB.<!-- /react-text --