Enhanced Hydrogen Evolution under Simulated Sunlight from Neutral Electrolytes on (ZnSe)0.85(CuIn0.7Ga0.3Se2)0.15 Photocathodes Prepared by a Bilayer Method

A (ZnSe)_0.85(CuIn_0.7Ga_0.3Se₂)_0.15 photocathode with a bilayer structure was fabricated and found to exhibit a photocurrent almost twice that of a photocathode with a monolayer structure during hydrogen evolution from water. The cathodic photocurrent reached maximum values of 12 and 4.9 mA cm^?2 at 0 and 0.6 V_RHE in a neutral phosphate buffer under simulated sunlight, while the half‐cell solar‐to‐hydrogen conversion efficiency was 3.0 % at 0.6 V_RHE, with a maximum value of 3.6 % at 0.45 V_RHE. Cross‐sectional mapping of the electron‐beam‐induced current established that the increased photocurrent can be attributed to improved uniformity at the solid–liquid junction in the bilayer sample, which results in enhanced carrier collection.     

氟催化废弃硅基还原剂与CO2还原转化反应

CO2是最重要的可再生碳源之一.为了将CO2转化为有用的有机化合物,我们研究了二种模型硅基"废"材料—乙硅烷和硅粉的反应活性.在这些反应中,氟盐的催化活性最高,在常压、在质子源水和硅基还原剂的存在下,CO2可转化为甲酸.原位NMR和动力学分析表明,含氢硅烷和五配位的硅物种分别是反应中间物和活性物种.     

Reciprocating Motion of a Self‐Propelled Object on a Molecular Layer

The mode change of a simple autonomous motor depending on the nature of a monolayer on water is investigated. A camphor disk is floated on a molecular layer of N‐stearoyl‐p‐nitroaniline (C₁₈ANA), which gives a surface‐pressure (π)–area per molecule (A) isotherm with a local maximum and a local minimum. The nature of the camphor motion changes depending on A, and in particular, reciprocating motion is observed at a lower A while cutting out its own trajectory of motion. The characteristic motion of a camphor disk depending on A is discussed in relation to the π–A isotherm of C₁₈ANA and the influence of the molecular interaction between molecules on the driving force of motion.     

Material properties controlling photocurrent on TiO2 aggregates with plane orientation for dye-sensitized solar cells

Effective design of a dye-sensitized solar cell (DSSC) requires a clear understanding of the reaction mechanisms of the constituent cell materials. The relationship between structural and photo-electrochemical properties of the photo-anodic materials is of the first priority for such investigations. Highly oriented aggregates of anatase phase TiO₂ nanoparticles were deposited on Indium Tin oxide (ITO) glass substrates; over which N719 dyes were adsorbed through electrophoretic deposition under a strong magnetic field. The properties were evaluated by electrochemical measurements, UV–VIS spectroscopy, and electrical resistance measurements. The results showed that the absorbed photon number in the TiO₂ aggregates with adsorbed dye and their resistivity showed different dependences on the orientation of the crystal plane in the TiO₂ particle. The dependence of the photocurrent on the plane orientation of aggregates of dye-sensitized TiO₂ nanoparticles has been determined from a combination of the electrical conductivity of TiO₂ aggregate and the amount of dye adsorbed on the surface of TiO₂.     

Supramolecular Light‐Harvesting Antennas of Metal‐Coordinated Bis(8‐Hydroxyquinoline)‐Substituted Porphyrin Networks

Artificial antenna complexes of metal‐coordinated bis(8‐hydroxyquinoline)‐substituted porphyrin networks that mimic antenna chromophores in plants were organized on titanium dioxide electrodes in photoelectrochemical cells. The generated photocurrents can be optimized according to the two ways of porphyrin self‐assembly due to the “antenna effect”: changing the number of assembled porphyrin monolayers and the number of generations of the metal‐coordinated porphyrin networks.     

Characterization of water adsorption onto carbonaceous materials produced from food wastes

The recycling of organic wastes has become very important and the development of technology for recycling organic wastes needs to sustain industrial development. In this study, techniques for producing carbonaceous materials from organic wastes are described and water adsorption is characterized. The organic wastes used are coffee grounds and oolong tea leaves carbonized at 673 to 1073 K. The iodine adsorption capacity of the carbonaceous materials increased with increased carbonization temperature. The amount of water adsorbed onto the carbonization materials produced from oolong tea leaves at 873 K for 2 h was the highest. The Freundlich constant 1/n and the differential heat of adsorption of the carbonaceous materials produced from oolong tea leaves were greater than that of the carbonaceous materials produced from coffee grounds. The ability to humidity control can be estimated by the difference between the amount of water adsorbed relative pressure 0.90 and that at relative pressure 0.55. The ability to humidity control was the greatest for the carbonaceous materials produced from the oolong tea leaves at 873 K for 2 h and did not depend upon the adsorption temperature. These results indicated that the carbonaceous materials produced from oolong tea leaves at 873 K for 2 h could have more humidity control.     

Brine shrimp lethality test active constituents and new highly oxygenated seco-prezizaane-type sesquiterpenes from Illicium merrillianum

In the study of bioactive substances in Illicium plants, the methanol extract of I. merrillianum showed brine shrimp lethality test (BST) activity at 200 microg/ml. Bioassay-guided fractionation of the BST active fractions resulted in the isolation of 4-O-methyleudesm-11-en-4alpha-ol, eudesmol-11-en-4alpha-ol and (-)-hinokinin as potent BST active compounds. On the other hand, four new highly oxygenated seco-prezizaane-type sesquiterpenes, merrilliortholactone (1), 2alpha-hydroxycycloparvifloralone (2), 2alpha-hydroxycycloparviflorolide (3), and 2alpha-hydroxyanisatin (4) were isolated from the BST-inactive polar fractions. The structures of new compounds were elucidated by extensive analyses of spectral data. Furthermore, the absolute configuration of 3 was established by the modified Mosher's method. Compounds 1--4 showed neither BST activity at 100 microg/ml nor neurite outgrowth-promoting activity.