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91.
Prolonged Hot Electron Dynamics in Plasmonic‐Metal/Semiconductor Heterostructures with Implications for Solar Photocatalysis 下载免费PDF全文
Joseph S. DuChene Brendan C. Sweeny Dr. Aaron C. Johnston‐Peck Dr. Dong Su Dr. Eric A. Stach Prof. Dr. Wei David Wei 《Angewandte Chemie (International ed. in English)》2014,53(30):7887-7891
Ideal solar‐to‐fuel photocatalysts must effectively harvest sunlight to generate significant quantities of long‐lived charge carriers necessary for chemical reactions. Here we demonstrate the merits of augmenting traditional photoelectrochemical cells with plasmonic nanoparticles to satisfy these daunting photocatalytic requirements. Electrochemical techniques were employed to elucidate the mechanics of plasmon‐mediated electron transfer within Au/TiO2 heterostructures under visible‐light (λ>515 nm) irradiation in solution. Significantly, we discovered that these transferred electrons displayed excited‐state lifetimes two orders of magnitude longer than those of electrons photogenerated directly within TiO2 via UV excitation. These long‐lived electrons further enable visible‐light‐driven H2 evolution from water, heralding a new photocatalytic paradigm for solar energy conversion. 相似文献
92.
Ştefan Ţălu Sebastian Stach Aman Mahajan Dinesh Pathak Tomas Wagner Anshul Kumar Ratish Kumar Bedi 《Surface and interface analysis : SIA》2014,46(6):393-398
This paper applies multifractal spectrum theory to characterize the structural complexity of 3D surface roughness of copper (II) tetrasulfophthalocyanine (CuTsPc) films on the indium tin oxide (ITO) substrate, obtained with atomic force microscopy (AFM) analysis. CuTsPc films were prepared by drop cast method on ITO substrate. CuTsPc films surface roughness was studied by AFM in tapping‐mode?, in air, on square areas of 2500 µm2. A novel approach, on the basis of computational algorithms for analysis of 3D roughness surface applied for AFM data, was presented. Results revealed that the 3D surface roughness of CuTsPc films prepared by drop cast method on ITO substrate can be described using the multifractal geometry. The generalized dimensions Dq and the multifractal spectrum f(α) provided quantitative values that characterize the local scale properties of CuTsPc films surface geometry at nanometer scale. Data provide valuable information to describe the spatial arrangement of 3D surface roughness of CuTsPc films on ITO substrate, which was not taken into account by classical surface statistical parameters. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
93.
E. Stach A. Dosch H. Hoff H. Contzen H. Lütke und P. Verbeck 《Fresenius' Journal of Analytical Chemistry》1914,53(7):440
Ohne Zusammenfassung 相似文献
94.
Magdalena Kurdziel Elżbieta Szczepaniec-Cięciak Ewa Żarnowska Jolanta Stach Wojciech Nitek Barbara Dąbrowska 《Journal of solution chemistry》2001,30(9):781-794
The solubilities of solid 1-hexene and 2-methylpentane in liquid argon at a temperature of 87.3 K and in liquid nitrogen at 77.4 K have been measured by the filtration method. The hydrocarbon contents in solutions were determined using gas chromatography. The experimental value of the mole fraction solubility of solid 1-hexene in liquid argon at 87.3 K is (3.87 ± 0.74) × 10-7 and (7.94 ± 2.47) × 10-9 in liquid nitrogen at 77.4 K. The experimental value of the mole fraction solubility of solid 2-methylpentane in liquid argon at 87.3 K is (1.45 ± 0.36) × 10-5 and (6.80 ± 2.16) × 10-8 in liquid nitrogen at 77.4 K. The Preston–Prausnitz method was used for calculation of the solubilities of solid hydrocarbons in liquid argon in the temperature range 84.0–110.0 K and in liquid nitrogen from 64.0 to 90.0 K. The solvent–solute interaction parameters 112 were also calculated. At 90.0 K, liquid argon is a better solvent for solid 1-hexene and 2-methylpentane than is liquid nitrogen. 相似文献
95.
EPR Investigations on a Copper Chelate of anα-Cyano-β-amino-dithioacryl Acid Ester EPR studies on copper(II) chelates of anα-cyano-β-amino-dithioacryl acid ester are reported. The EPR spectra were obtained from solutions, diamagnetically diluted powders, and single-crystals which are stable for a short time only. The corresponding nickel(II) chelate was used as host lattice. The 14N ligand hyperfine structure observed in the spectra is in agreement with a [CuN2S2] coordination sphere. In some orientations of the recorded angular dependencies the EPR spectra show a hyperfine splitting due to the interaction of the unpaired electron with the N? H protons. In addition spin flip satellite lines are observed in the single-crystal spectra. The g, ACu and AN tensors obtained from the powder and single-crystal spectra have an axial symmetry within the experimental errors. The unpaired electron occupies a MO which consists mainly of the copper 3dxy and the corresponding donor atom orbitals. The co-valency of the metal ligand bond is very high. 相似文献
96.
The following paper describes the generalization of the microwave resonance method for measuring the phase between relative changes of the concentration and collision frequency of electrons. It also presents the results of measuring the phase between the above-mentioned parameters of plasma in neon, in which slow and fast ionization waves are propagated which, have been obtained by the described method.In conclusion we would like to thank Prof. Dr. V. Kunzl, head of the Department of Electronics and Vacuum Physics, at the Faculty of Mathematics and Physics, Charles University, for making this work possible, and Docent Dr. M. icha C.Sc., for much valuable advice which contributed to the successful completion of this work. 相似文献
97.
Shekhar M Wang J Lee WS Williams WD Kim SM Stach EA Miller JT Delgass WN Ribeiro FH 《Journal of the American Chemical Society》2012,134(10):4700-4708
The water-gas shift (WGS) reaction rate per total mole of Au under 7% CO, 8.5% CO(2), 22% H(2)O, and 37% H(2) at 1 atm for Au/Al(2)O(3) catalysts at 180 °C and Au/TiO(2) catalysts at 120 °C varies with the number average Au particle size (d) as d(-2.2±0.2) and d(-2.7±0.1), respectively. The use of nonporous and crystalline, model Al(2)O(3) and TiO(2) supports allowed the imaging of the active catalyst and enabled a precise determination of the Au particle size distribution and particle shape using transmission electron microscopy (TEM). Further, the apparent reaction orders and the stretching frequency of CO adsorbed on Au(0) (near 2100 cm(-1)) determined by diffuse reflectance infrared spectroscopy (DRIFTS) depend on d. Because of the changes in reaction rates, kinetics, and the CO stretching frequency with number average Au particle size, it is determined that the dominant active sites are the low coordinated corner Au sites, which are 3 and 7 times more active than the perimeter Au sites for Au/Al(2)O(3) and Au/TiO(2) catalysts, respectively, and 10 times more active for Au on TiO(2) versus Al(2)O(3). From operando Fourier transform infrared spectroscopy (FTIR) experiments, it is determined that the active Au sites are metallic in nature. In addition, Au/Al(2)O(3) catalysts have a higher apparent H(2)O order (0.63) and lower apparent activation energy (9 kJ mol(-1)) than Au/TiO(2) catalysts with apparent H(2)O order of -0.42 to -0.21 and activation energy of 45-60 kJ mol(-1) at near 120 °C. From these data, we conclude that the support directly participates by activating H(2)O molecules. 相似文献
98.
Joachim Stach Reinhard Kirmse Ulrich Abram Wolfgang Dietzsch Jan H. Noordik Karel Spee Kees P. Keijzers 《Polyhedron》1984,3(4):433-442
A single-crystal ESR study of the mixed-ligand complex tetra - n - butylammonium - (maleonitriledithiolato)(diethyl - di - selenocarbamato)cuprate(II) diamagnetically diluted by the corresponding Ni(II) complex, and the crystal and molecular structure of the host complex determined by a single-crystal X-ray diffraction study, is reported. (n-Bu4N)[Ni(mnt)(et2dsc)] is monoclinic, space group C2/c, with eight molecules in the unit cell; a = 19.932(9) Å, b = 9.597(3) Å, c = 37.580(13) Å and β = 101.32(3)°. Based on the structure the spin Hamiltonian parameters have been calculated from the results of extended Hückel molecular orbital calculations and compared with the experimentally obtained values. The principal axes of the g? and the metal hyperfine tensor do not coincide reflecting the large influence of the et2dsc? ligand for which this behaviour was found to be typical. A comparison between the ESR parameters and the Mulliken spin densities of the mixed-ligand chelate and the corresponding parent complexes shows that in the former one spin density appears to be transfered from the S atoms to the Se atoms of the et2dsc? part of the complex resulting in an increased CuSe covalency. Back-bonding effects were considered in discussing the bonding properties. 相似文献
99.
A note on Ky Fan's minimax theorem 总被引:1,自引:0,他引:1
100.
By oxidation of nitridotechnetate(V) complexes of the type [TcN(parSS)2]0,2? (parSS = diethyldithiocarbamate, diphenyldithiophosphinate and maleonitrile-dithiolate) with chlorine the Tc6+ complex anion [TcNCl5]2? was created and studied by EPR in liquid and frozen solutions. The EPR spectra are in agreement with a d1 (S = 1/2) system. The hyperfine interactions are used to characterize the bonding properties in the molecular orbital of the unpaired electron. 相似文献