A critical factor limiting the rates of photocatalytic reactions, including water splitting, on oxide semiconductors is high rate charge-carrier recombination. In this contribution, we demonstrate that issue can be alleviated significantly by combining a semiconductor photocatalyst with tailored plasmonic-metal nanostructures. Plasmonic nanostructures support formation resonant surface plasmons in response to photon flux, localizing electromagnetic energy close their surfaces. We present...

Oxidation of functioning copper has restricted its applicability as a catalyst for commercially important epoxidation propylene to form oxide. Here, we report that steady-state selectivity in on (Cu) nanoparticles increases sharply when the is illuminated with visible light. The increase accompanied by light-induced reduction surface Cu atoms, which brought about photoexcitation localized plasmon resonance (LSPR) Cu. We discuss multiple mechanisms LSPR weakens Cu-O bonds, reducing Cu2O.

Abstract Plasmonic metal nanoparticles enhance chemical reactions on their surface when illuminated with light of particular frequencies. It has been shown that these processes are driven by excitation localized plasmon resonance (LSPR). The interaction LSPR adsorbate orbitals can lead to the injection energized charge carriers into adsorbate, which result in transformations. mechanism process (and role LSPR) is not well understood. Here we shed specifics this coupling optical...

Plasmonic metal nanoparticles can efficiently convert the energy of visible photons into hot charge carriers within nanoparticles. These energetic transfer to molecules or semiconductors, chemically attached nanoparticles, where they induce photochemical transformations. Classical models photoinduced excitation and in metals suggest that majority rapidly decay nanostructure before are transferred neighboring molecule semiconductor, therefore, efficiency is low. Herein, we present...

We use microkinetic modeling to demonstrate that deviations from ideal Tafel kinetics, which assume a linear relationship between overpotential and log-current, are an inherent property of multi-step heterogeneous electrocatalytic reactions. show in general, behavior can often be attributed simultaneous increase the rate rate-limiting elementary step change number available active sites on electrode as is induced. Our analysis shows oxygen reduction reaction (ORR) Pt electrodes, exhibits...

Composite materials composed of optically active Ag nanostructures and TiO2 photocatalysts show enhanced photoactivity compared to the pure in decomposition methylene blue. The photochemical activity is attributed radiative transfer energy, mediated by surface plasmons, from particles semiconductor leading higher concentrations charge carriers (e−/h+ pairs) therefore activity. We demonstrate that performance composite a strong function size shape nanostructures. This can be explained size-...

Controlling selectivity in heterogeneous catalysis is critical for the design of environmentally friendly catalytic processes that minimize production undesired byproducts and operate with high energy efficiency. We show Ag nanowire catalysts exhibit higher ethylene epoxidation reaction than conventional spherical particle catalysts. The was attributed to a concentration Ag(100) surface facets compared Density functional theory calculations transformation oxametallacycle intermediate form...

We demonstrate the design of composite plasmonic metal/semiconductor photocatalysts, which show enhanced visible light photocatalytic activity compared to semiconductor alone. that overlap between illumination source spectrum, absorbance spectrum and metal nanoparticle surface plasmon resonance provides a useful descriptor for predicting relative rate enhancements induced by plasmons photocatalysts with similar arrangements building blocks. also optical simulations can be used predict value...

Nanostructured carbides are refractory materials with high surface areas that could be used as alternatives to the oxide widely support for heterogeneous catalysts. Carbides also catalytically active a variety of reactions, offering additional opportunities tune overall performance catalyst. In this paper we describe synthesis molybdenum carbide supported platinum (Pt/Mo2C) catalysts and their rates water gas shift reaction. The method allowed interaction metal precursor native, unpassivated...

Hitting the limits on propene synthesis The greater abundance of propane from shale gas has spurred efforts to use it as a propylene feedstock. Direct dehydrogenation catalysts consisting platinum–tin alloy nanoparticles supported alumina often must run with hydrogen dilution avoid carbon buildup and excess tin segregation. Motagamwala et al. report that interact more weakly silica support metals thus do not segregate. undiluted reactants allowed reaction near thermodynamically limit about...

ADVERTISEMENT RETURN TO ISSUEPREVViewpointNEXTA Viewpoint on Direct Methane Conversion to Ethane and Ethylene Using Oxidative Coupling Solid CatalystsBrittany Lancaster Farrell, Valentina Omoze Igenegbai, Suljo Linic*View Author Information Department of Chemical Engineering, University Michigan, NCRC Building 28, 2800 Plymouth Road, Ann Arbor, Michigan 48109, United States*E-mail: [email protected]. Tel.: +1 734 647 7984.Cite this: ACS Catal. 2016, 6, 7, 4340–4346Publication Date (Web):May...

Propylene production through propane dehydrogenation (PDH) is endothermic, and high temperatures required to achieve acceptable conversions lead low selectivity severe carbon-induced deactivation of conventional catalysts. We developed a catalyst-membrane system that removes the hydrogen by-product can thus exceed equilibrium limits. In this codesigned system, silica/alumina (SiO

We show that there is a family of adsorbate-substrate systems do not follow the trends in adsorption energies predicted by d-band model. A physically transparent model used to analyze this phenomenon. found these pairs are characterized repulsive interaction substrate with renormalized adsorbate states. The exceptions mainly associated adsorbates having almost completely filled valence shell, and substrates nearly fully occupied d-band, e.g., OH, F, or Cl on metals alloys d(9) d(10) surface atoms.

Temperature programmed desorption, high-resolution electron energy loss spectroscopy (HREELS), and density functional theory (DFT) were used to investigate the adsorption reaction of ethylene oxide (EO) on Ag(111) surface. When EO is dosed onto at 140 K it adsorbs molecularly, desorbing without approximately 200 K. On other hand, when 250 K, ring-opening activated, a stable surface intermediate formed. This reacts 300 re-form plus few products. HREELS DFT studies suggest that this...

Surface science experiments, DFT calculations, and kinetic isotope effect data are utilized to understand the elementary steps that govern selectivity of silver catalysts for partial oxidation ethylene produce oxide. It is proposed selective unselective pathways proceed via a common intermediate, surface oxametallacycle. The structures transition states leading from this intermediate products calculated. From calculated Gibbs free energies activation competing pathways, it possible predict...