g-C3N4 quantum dots-modified mesoporous TiO2–SiO2 for enhanced photocatalysis

Research on Chemical Intermediates - The utilization of TiO2-based photocatalysts for an efficient removal of dye pollutants is limited due to their low surface area, high recombination rate of the...     

Synergic liquid/liquid extraction of lithium and sodium with 4-acyl-5-pyrazolones with bulky substituents and tri-n-octylphosphine oxide

The synergic liquid/liquid extraction of lithium and sodium with 4-acyl-5-pyrazolones having bulky substituents and tri-n-octylphosphine oxide (TOPO) is described. The maximum percentage extraction and the separation of lithium and sodium were improved by introducing bulky substituents. Quantitative extraction (? 99% ) of lithium could be achieved by adduct formation with TOPO, which enhanced the extraction much more than did triphenylphosphine oxide. The extraction decreased in the solvent order cyclohexane ? benzene ? chloroform, which is the general trend in synergic extractions.     

Simultaneous determination of tungsten and molybdenum in sea water by catalytic current polarography after preconcentration on a resin column

The simultaneous determination of tungsten and molybdenum in sea water is based on preconcentration by column extraction with 7-(1-vinyl-3,3,5,5-tetramethylhexyl)-8-quinolinol (Kelex- 100) resin, and measurement of the polarographic catalytic currents obtained in a solution of chlorate, benzilic acid and 2-methyl-8-quinolinol. When the concentration factor is 50, the detection limits are 2.4 pM for tungsten and 17 pM for molybdenum (for a signal-to-noise ratio of 3). The precision of the determination is ca. 10% for 67 pM tungsten and ca. 5% for 106 nM molybdenum in sea water (n=4). Results for sea water and other natural waters are presented.     

Observation of the d3Pi(g)<--c3Sigma(u)+ band system of C2

A new band system of C(2), d (3)Pi(g)<--c (3)Sigma(u) (+) is observed by laser induced fluorescence spectroscopy, constituting the first direct detection of the c (3)Sigma(u) (+) state of C(2). Observations were made by laser excitation of c (3)Sigma(u) (+)(v(")=0) C(2), produced in an acetylene discharge, to the d (3)Pi(g)(v(')=3) level, followed by detection of Swan band fluorescence. Rotational analysis of this band yielded rotational constants for the c (3)Sigma(u) (+)(v(")=0) state: B(0)=1.9218(2) cm(-1), lambda(0)=-0.335(4) cm(-1) and gamma(0)=0.011(2) cm(-1). The vibrational band origin was determined to be nu(3-0)=15861.28 cm(-1).     

Design of Superhydrophobic Porous Coordination Polymers through the Introduction of External Surface Corrugation by the Use of an Aromatic Hydrocarbon Building Unit

We demonstrate a new approach to superhydrophobic porous coordination polymers by incorporating an anisotropic crystal morphology featuring a predominant surface that is highly corrugated and terminated by aromatic hydrocarbon moieties. The resulting low‐energy surface provides particularly promising hydrophobic properties without the need for postsynthetic modifications or surface processing that would block the porosity of the framework. Consequently, hydrophobic organic molecules and water vapor are able to penetrate the surface and be densely accommodated within the pores, whereas bulk water is repelled as a result of the exterior surface corrugation derived from the aromatic surface groups. This study provides a new strategy for the design and development of superhydrophobic porous materials.     

Application of photoluminescence spectroscopy to elucidate photocatalytic reactions at the molecular level

The present review covers the outline of the application of photoluminescence (PL) spectroscopy to understand the photocatalytic reactions on the bulk semiconducting materials and highly dispersed metal oxide single-site heterogeneous catalysts at their working states. The first part focuses on the applications of PL spectroscopy to elucidate the surface active sites and surface band structures of the inorganic and organic bulk semiconducting photocatalysts at their working states. The second part describes the applications of in situ PL spectroscopy to elucidate the surface active sites of the highly dispersed metal oxide single-site heterogeneous catalysts and their roles in photocatalytic reactions at the molecular level. The last part is a brief conclusion and future direction of PL studies.

     

Photocatalytic selective oxidation of CO with O2 in the presence of H2 over highly dispersed chromium oxide on silica under visible or solar light irradiation

A highly dispersed Cr⁶⁺-oxide species on silica (Cr/SiO₂) was found to act as an efficient photocatalyst for the selective oxidation of CO into CO₂ with O₂ in the presence of H₂ under visible (λ>420 nm) or solar light irradiation at 293 K. UV-Vis, photoluminescence and FT-IR investigations revealed that the selective reactivity of the photoexcited tetrahedral Cr⁶⁺-oxide species ([Cr⁵⁺−O⁻]^*) with CO, as well as the high reactivity of the photoreduced Cr⁶⁺-oxide species (Cr⁴⁺-oxide species) with O₂ both play significant roles in this reaction.     

High-conversion-efficiency organic dye-sensitized solar cells with a novel indoline dye

An indoline dye (D205), the synthesis method of which is disclosed in this report, gave high-efficiency organic dye-sensitized solar cells (9.52%) using an anti-aggregation reagent (chenodeoxycholic acid).