On the behaviour of Au plasmonic nanoparticles during hydrogen evolution at p-Si

Brewster Angle Reflectometry (BAR) and spectral photocurrent analysis show that Au nanoparticles are in a resonant state during light-induced hydrogen evolution with unpolarized light near-normal incidence. Keggin-type phosphododecamolybdate (PMo₁₂O₄₀^3?) anions were used as reducing and stabilizing agents to form novel Au nanoparticles (Au-NPs). BAR was employed to analyze the resonant optical response after adsorption to the surface of hydrogen terminated p-Si(111):H (1 × 1) and SiO₂. Proton reduction in 1 M H₂SO₄ occurs at asymmetric Au-NPs where also multipole field effects influence the plasmonic behaviour. In a comparative discussion, the contribution of surface plasmon polariton excitation to the observed pronounced photocurrent enhancement is outlined.     

Lower rim substituted p-tert-butyl calix[4]arene; Part 14. Synthesis, structures and binding studies of calix[4]arene thioamides

A number of p-tert-butylcalix[4]arene thioamides were synthesized and characterized by ¹H-NMR and elemental analysis. Compounds 1–5 are O-substituted derivatives with –CH₂–C(=S)–N–X groups, where NX = morpholidyl, NEt₂, NHC₂H₄Ph, NHCH₂Ph and NHEt, respectively. The X-ray structures of the ligands 1, 3, 5 and of the complex 3·Pb(ClO₄)₂, (compound 6), are presented and their slightly distorted cone conformation is established. The influence of the nature of the thioamide functions (secondary or tertiary) on the extractability of some selected metal cations was investigated. Whereas all these calixarenes show the highest extraction level for Ag⁺, tertiary thioamides are more efficient extractants for Pb²⁺ than secondary thioamides.     

Activation of bimetallic PtFe nanoparticles with zeolite-type cesium salts of vanadium-substituted polyoxometallates toward electroreduction of oxygen at low Pt loadings for fuel cells

Journal of Solid State Electrochemistry - The catalytic activity of commercial carbon-supported PtFe (PtFe/C) nanoparticles admixed with mesoporous polyoxometalate Cs3H3PMo9V3O40, (POM3-3–9),...     

Elucidation of activity of copper and copper oxide nanomaterials for electrocatalytic and photoelectrochemical reduction of carbon dioxide

Copper- and copper oxide–based materials are, in principle, promising components (supports, reactive sites, and visible light–absorbing semiconductors) of electrocatalysts and photocathodes for reduction of carbon dioxide. Electrochemical and photoelectrochemical approaches are generally suitable for the low-temperature CO₂-conversion to carbon-based simple organic fuels or utility chemicals.Different concepts of utilization, including nanostructuring, doping, admixing, preconditioning, modification, or functionalization of various copper- and copper oxide–based systems for catalytic electroreduction and photoelectrochemical reduction of CO₂ are elucidated, as well as important strategies to enhance the systems' overall activity and stability are discussed.     

Thermal characteristics of novel NaH2PO4/NaHSO4 flame retardant system for polyurethane foams

The thermal decomposition of iminodiacetic, oxydiacetic, and thiodiacetic acids in helium atmosphere has been studied by means of thermogravimetry (TG), differential thermal analysis (DTA) and temperature-programmed pyrolysis directly coupled with mass spectrometry (TPPy-MS). Evolved gas analysis (EGA) profiles of iminodiacetic and oxydiacetic acids were obtained and compared with TG and DTA profiles. The decomposition of iminodiacetic acid forms water, CO, CO₂, CH₃CN, HCN and some hydrocarbons. After water evolution a cyclic anhydride is formed, as well as for oxydiacetic acid. Thiodiacetic acid vaporizes without decomposition.     

Enhanced Water Splitting at Thin Film Tungsten Trioxide Photoanodes Bearing Plasmonic Gold–Polyoxometalate Particles

Tungsten trioxide (WO₃) is one of a few stable semiconductor materials liable to produce solar fuel by photoelectrochemical water splitting. To enhance its visible light conversion efficiency, we incorporated plasmonic gold nanoparticles (Au NPs) derivatized with polyoxometalate (H₃PMo₁₂O₄₀) species into WO₃. The combined plasmonic and catalytic effect of Au NPs anchored to the WO₃ surface resulted in a large increase of water photooxidation currents. Shielding the Au NPs with polyoxometalates appears to be an effective means to avoid formation of recombination centers at the photoanode surface.     

Column Chromatography and Preparative TLC for Isolation and Purification of Coumarins from Peucedanum verticillare L. Koch ex DC

JPC – Journal of Planar Chromatography – Modern TLC - Preparative separation and isolation of coumarins from petroleum ether and methanol extracts of the fruits and roots of Peucedanum...     

Synthesis of Stable Dolichylphosphomannose Analogues

Four oleyl or dolichyl thiophosphate esters 16, 17, 21 , and 22 , analogues of Dol‐P‐Man possessing C(1)? S and/or P? S bonds, were synthesized as potential inhibitors of mannosyl transferases operating in the endoplasmic reticulum (ER). The β‐mannosyl derivatives were prepared by a Mitsunobu reaction of 2,3,4,6‐tetra‐O‐acetyl‐α‐D ‐mannopyranose ( 1 ) with the thiophosphate 2 that provided O‐ and S‐glycosides with good‐to‐excellent diastereoselectivity. A second route to β‐mannosyl derivatives is based on the phosphitylation of the β‐D ‐mannopyranosyl thiol 3 with the phosphoramidites 4a and 4b . Oxidation of the intermediate oleyl thiophosphite with t‐BuOOH led to mono‐ and dithiophosphates. The thiophospholipids 16, 21 , and 22 were inactive as inhibitors of the Man₆(GlcNAc)₂‐PP‐Dol glycolipid elongation.     

Pair production of J/ψ as a probe of double parton scattering at LHCb

We argue that the recent LHCb observation of J/ψ-pair production indicates a significant contribution from double parton scattering, in addition to the standard single parton scattering component. We propose a method to measure the double parton scattering at LHCb using leptonic final states from the decay of two prompt J/ψ mesons.