Importance of surface carbide formation on the activity and selectivity of Pd surfaces in the selective hydrogenation of acetylene

A recent experimental investigation (Kim et al. J. Catal. 306 (2013) 146-154) on the selective hydrogenation of acetylene over Pd nanoparticles with different shapes concluded that Pd(100) showed higher activity and selectivity than Pd(111) for acetylene hydrogenation. However, our recent density functional calculations (Yang et al. J. Catal. 305 (2013) 264-276) observed that the clean Pd(111) surface should result in higher activity and ethylene selectivity compared with the clean Pd(100) surface for acetylene hydrogenation. In the current work, using density functional theory calculations, we find that Pd(100) in the carbide form gives rise to higher activity and selectivity than Pd(111) carbide. These results indicate that the catalyst surface is most likely in the carbide form under the experimental reaction conditions. Furthermore, the adsorption energies of hydrogen atoms as a function of the hydrogen coverage at the surface and subsurface sites over Pd(100) are compared with those over Pd(111), and it is found that the adsorption of hydrogen atoms is always less favoured on Pd(100) over the whole coverage range. This suggests that the Pd(100) hydride surface will be less stable than the Pd(111) hydride surface, which is also in accordance with the experimental results reported.

A chemically unlocked binary molecular switch

A highly luminescent and sensitive terbium complex of a ligand comprising of a phthalimide group appended to a DO3A moiety is an active pH sensor that is conditional on its previous pH. © 2012 The Royal Society of Chemistry.

Structure-tunable Janus fibers fabricated using spinnerets with varying port angles

The preparation of Janus fibers using a new side-by-side electrospinning process is reported. By manipulating the angle between the two ports of the spinneret emitting the working fluids, Janus nanofibers with tunable structures in terms of width, interfacial area and also volume of each side can be easily fabricated.

Multiple source quantum well model of porous silicon light emission

Based on photoluminescence, Fourier transform infrared spectroscopy, and atomic force microscopy results, a new light emitting model for porous silicon (multiple source quantum well model) is proposed.

Computational intelligence

The Centre for Intelligent Systems (CIS) is a multidisciplinary research and development centre, founded in 2001, in a very young university, the University of Algarve, in the south of Portugal. The centr's mission is to promote fundamental research in Computational Intelligence (CI) methodology.

Catchment influences on the hydrological flows to lake terra alta (Linhares, ES, Brazil) and ecohydrology perspectives

Dissertação de mestrado, Ecohidrologia, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

L'Écho de Paris

1891/04/01 (Numéro 2508).

De clase

Programas, proyectos y red de portales

Niagara Parks Commission annual report, 1907.

Printed by Order of the Legislative Assembly of Ontario.

Localización, construcción y prueba de pozo en una falla geológica de dilusión

Tesis (Maestría en Hidrología Subterránea) UANL

Caracterización del acuifero de Ciudad Universitaria de la Universidad Autónoma de Nuevo León

Tésis (Maestría en Ciencias con Especialidad en Hidrología Subterranea) UANL.

Evaluación del acuitardo somero en la región de Mendéz, Tamaulipas y sus aplicaciones para instalación de un centro integral para el manejo y aprovechamiento de residuos industriales

Tesis (Maestría en Ciencias con Especialidad en Hidrología Subterranea) UANL

Comportamiento hidráulico y geoquímico del acuífero granular de la cuenca de Paderón-Icamole, entre los estados de Nuevo León y Coahuila, en México

Tesis (Maestría en Ciencias con Especialidad en Hidrología Subterranea) UANL.