Construction of TiO2 /SrTiO3 Heterojunction Derived from Monolayer Ti3 C2 MXene for Efficient Photocatalytic Overall Water Splitting.

Construction of heterojunction at the atomic scale to ensure efficient charge separation for improvement of photocatalytic water splitting is challenging. Herein, a facile hydrothermal method has been applied for the in situ fabrication of TiO2 /SrTiO3 heterojunction, using the monolayer Ti3 C2 MXene as the template and reactant. It is found that the sample with the hydrothermal reaction time of 60 min exhibits the highest H2 evolution rate with the sacrificial reagent, due to the efficient charge separation of TiO2 /SrTiO3 heterojunction as Ti3 C2 derivative. In addition, the sample shows the best overall water splitting performance at a hydrothermal reaction time of 120 min, where TiO2 is nearly converted to SrTiO3 , due to the fast kinetic process and low structural defects of SrTiO3 . This work not only provides a simple strategy for the fabrication of heterojunction photocatalysts but also demonstrates the difference in optimization of half-reaction and overall water splitting reaction.

Achieving Efficient Incorporation of π-Electrons into Graphitic Carbon Nitride for Markedly Improved Hydrogen Generation.

A rapid and highly efficient strategy for introducing C into g-C3 N4 involves copolymerizing π-electron-rich barbituric acid with melamine via a facile microwave-assisted heating, thereby eliminating the issues in conventional electric furnace heating, such as the severe volatilization, owing to the mismatch of the sublimation temperatures of barbituric acid and melamine. The g-C3 N4 catalyst after optimizing the C-doping content actively generates increased amounts of H2 under visible light exposure with the highest H2 generation rate of 25.0 µmol h-1 , which is nearly 20 times above that using g-C3 N4 produced by conventional electric furnace heating of two identical monomers (1.3 µmol h-1 ). As such, the microwave-assisted heating strategy may stand out as an extremely simple route to incorporating π-electrons into g-C3 N4 with markedly improved photocatalytic performance.

A self-assembled nanohybrid composed of fluorophore-phenylamine nanorods and Ag nanocrystals: energy transfer, wavelength shift of fluorescence and TPEF applications for live-cell imaging.

A fluorophore-phenylamine derivative (L) has been coupled with silver nanocrystals (NCs) to construct an L-Ag nanohybrid. Owing to synergic effects of the L and Ag components, the exciton-plasmon interactions between L and Ag increase the strength of the donor-acceptor interaction within the nanohybrid, a fact that results in an energy-transfer process and further brings about a dramatic redshift of single-photon absorption and fluorescence, and a decreased fluorescence FL lifetime. The coupling effect also leads to enhancement of a series of nonlinear optical properties, including two-photon-excited fluorescence (TPEF), two-photon-absorption (TPA) cross section (δ), two-photon-absorption coefficient (ß), nonlinear refractive index (γ), and third order nonlinear optical susceptibility (χ((3))). The enhanced two-photon fluorescence of the nanohybrid is proven to be potentially useful for two-photon microscopy of live cells, such as HepG2. Moreover, cytotoxicity tests show that the low-micromolar concentrations of the nanohybrid do not cause significant reduction in cell viability over a period of at least 24 h and should be safe for further biological studies.

[Synthesis, spectra, nonlinear optical properties and theoretical calculations of metal complexes containing phenothiazine ligand].

A new ligand, S-benzyl-(-N-[10-ethylphenothiazinyl-3yl]-methylene] dithiocarbazate (abbreviated as HL), and its complexes ML2 (M=Co and Hg) have been synthesized and fully characterized by elemental analyses, EI-MS, 1H NMR, IR, UV-Vis spectra, and photoluminescence measurement. All of the compounds emit an olivine color in DMF solution. The emission maximum (lambdamax(em)), and fluorescence quantum (phif) of each compound were measured. Nonlinear Optical properties of the HL and ML2 were studied by z-scan technique. Nonlinear absorption coefficient beta were measured to be 0.71, 0.19 and 0.395 cm x GW(-1). Theoretical calculations (RHF/PM3) were consistent with the experimental results.

[Photometric determination of cobalt by the formation of a multi-ligand complex of Co(II)-C16H16N2S2O2-DEA].

The new ligand vanillin S-benzyldithocarbazte(HL) and its complex Co(II)-C16H16N2S2O2-DEA was synthesized and characterized by IR, UV-Vis. The optimum color conditions of the complex in 95% ethanol solution(including reaction temperature T, heating time t, and the concentrations of the three components) have been studied by quadratic regression orthogonal design method. According to the quadratic-regression equation, the maximum absorption intensity and optimum color conditions of the complex were calculated. The results were consistent with those gotten by experiment. The influences of common ions on the determination of cobalt and the methods to eliminate the influence are investigated. The maximum absorption peak of the complex is found at 404 nm and molar absorptivity is 5.29 x 10(4) L.mol-1.cm-1. Beer's law is obeyed in the range of 0-20 micrograms.(25 mL)-1 for Co(II). The composition of Co2+ to HL, and DEA in the complex is 1:2:1. The new method was successfully utilized to the determination of cobalt in VB12 and medicine.