16 research outputs found
Controlling the Production of Acid Catalyzed Products of Furfural Hydrogenation by Pd/TiO2
We demonstrate a modified sol-immobilization procedure using (MeOH)x/(H2O)1-x solvent mixtures to prepare Pd/TiO2 catalysts that are able to reduce the formation of acid catalyzed products, e. g. ethers, for the hydrogenation of furfural. Transmission electron microscopy found a significant increase in polyvinyl alcohol (PVA) deposition at the metal-support interface and temperature programmed reduction found a reduced uptake of hydrogen, compared to an established Pd/TiO2 preparation. We propose that the additional PVA hinders hydrogen spillover onto the TiO2 support and limits the formation of Brønsted acid sites, required to produce ethers. Elsewhere, the new preparation route was able to successfully anchor colloidal Pd to the TiO2 surface, without the need for acidification. This work demonstrates the potential for minimizing process steps as well as optimizing catalyst selectivity – both important objectives for sustainable chemistry
Interstitial modification of palladium nanoparticles with boron atoms as a green catalyst for selective hydrogenation.
Lindlar catalysts comprising of palladium/calcium carbonate modified with lead acetate and quinoline are widely employed industrially for the partial hydrogenation of alkynes. However, their use is restricted, particularly for food, cosmetic and drug manufacture, due to the extremely toxic nature of lead, and the risk of its leaching from catalyst surface. In addition, the catalysts also exhibit poor selectivities in a number of cases. Here we report that a non-surface modification of palladium gives rise to the formation of an ultra-selective nanocatalyst. Boron atoms are found to take residence in palladium interstitial lattice sites with good chemical and thermal stability. This is favoured due to a strong host-guest electronic interaction when supported palladium nanoparticles are treated with a borane tetrahydrofuran solution. The adsorptive properties of palladium are modified by the subsurface boron atoms and display ultra-selectivity in a number of challenging alkyne hydrogenation reactions, which outclass the performance of Lindlar catalysts
Cathodes for electrochemical carbon dioxide reduction to multi-carbon products: part II rapid improvement in cathode performance
This is Part II of a focused review of recent highlights in the literature in cathode development for low temperature electrochemical carbon dioxide and carbon monoxide reduction to multicarbon (C2+) products. Part I (1) introduced the role of CO2 reduction in decarbonising the chemical industry and described the catalysts and modelling approaches. Part II describes in situ characterisation to improve the understanding and development of catalysts, the catalyst layer and the gas diffusion layer.</p
Cathodes for electrochemical carbon dioxide reduction to multi-carbon products: part I : a focused review of recent highlights
This is a focused review of recent highlights in the literature in cathode development for low temperature electrochemical carbon dioxide and carbon monoxide reduction to multi-carbon (C2+) products. The major goals for the field are to increase Faradaic efficiency (FE) for specific C2+ products, lower cell voltage for industrially relevant current densities and increase cell lifetime. A key to achieving these goals is the rational design of cathodes through increased understanding of structure-selectivity and structure-activity relationships for catalysts and the influence of catalyst binders and gas diffusion layers (GDLs) on the catalyst microenvironment and subsequent performance
Interstitial modification of palladium nanoparticles with boron atoms as a green catalyst for selective hydrogenation.
Lindlar catalysts comprising of palladium/calcium carbonate modified with lead acetate and quinoline are widely employed industrially for the partial hydrogenation of alkynes. However, their use is restricted, particularly for food, cosmetic and drug manufacture, due to the extremely toxic nature of lead, and the risk of its leaching from catalyst surface. In addition, the catalysts also exhibit poor selectivities in a number of cases. Here we report that a non-surface modification of palladium gives rise to the formation of an ultra-selective nanocatalyst. Boron atoms are found to take residence in palladium interstitial lattice sites with good chemical and thermal stability. This is favoured due to a strong host-guest electronic interaction when supported palladium nanoparticles are treated with a borane tetrahydrofuran solution. The adsorptive properties of palladium are modified by the subsurface boron atoms and display ultra-selectivity in a number of challenging alkyne hydrogenation reactions, which outclass the performance of Lindlar catalysts
Nanostructured ceramic membranes with metal functionalization for catalytic oxidation of antibiotics at CERAMPOL project
Synthesis, Alignment, and Magnetic Properties of Monodisperse Nickel Nanocubes
This Communication describes the synthesis of highly
monodispersed
12 nm nickel nanocubes. The cubic shape was achieved by using trioctylphosphine
and hexadecylamine surfactants under a reducing hydrogen atmosphere
to favor thermodynamic growth and the stabilization of {100} facets.
Varying the metal precursor to trioctylphosphine ratio was found to
alter the nanoparticle size and shape from 5 nm spherical nanoparticles
to 12 nm nanocubes. High-resolution transmission electron microscopy
showed that the nanocubes are protected from further oxidation by
a 1 nm NiO shell. Synchrotron-based X-ray diffraction techniques showed
the nickel nanocubes order into [100] aligned arrays. Magnetic studies
showed the nickel nanocubes have over 4 times enhancement in magnetic
saturation compared to spherical superparamagnetic nickel nanoparticles
NSR–SCR Combined Systems: Production and Use of Ammonia
International audienceThis chapter gives a critical overview of the recent advances in NOx abatement in excess of oxygen based on the combination of the NOx storage-reduction (NSR) and Selective Catalytic Reduction (SCR) processes. Ammonia may be produced during the regeneration step of NSR catalyst, by the direct reaction (NOx + H2) or/and the isocyanate route. Recent literatur