Fernando Coloma-Pascual

University of Alicante | UA · Research Technical Services

The catalytic performance of nanoparticles (NPs) of Ag anchored on different supports was evaluated during the selective hydrogenation of 1‐pentyne and the purification of a mixture of 1‐pentene/1‐pentyne (70/30 vol %). The catalysts were identified: Ag/Al (Ag supported on ɣ‐Al2O3), Ag/Al−Mg (Ag supported on ɣ‐Al2O3 modified with Mg), Ag/Ca (Ag sup...

In this work, the impregnation order of the second metal and the catalytic performance of low loaded Pd and Ni bimetallic catalysts were studied using different supports (γ-Al2O3, γ-Al2O3–Mg, CaCO3 and RX3). These catalysts were assessed in the selective hydrogenation of 1-pentyne and the purification of a mixture of 1-pentene/1-pentyne 70/30 vol%....

Pyrolysis gasoline (PyGas) is an unstable byproduct of the pyrolysis of naphtha and other hydrocarbons for the production of olefins. PyGas is stabilized by hydrogenation at mild conditions. The hydrogenation of styrene to ethylbenzene is considered a model test reaction for studying the selectivity of the catalysts because it has the slowest rate...

BACKGROUND Pd nanoparticles over different supports were evaluated during the alkyne selective hydrogenation of medium chain (C7 and C5) and the 1‐pentene purification at mild operational conditions (150 kPa and 303 K). The role of support and chloride was investigated; γ‐Al2O3, γ‐Al2O3 modified with Mg, CaCO3 and activated carbon were used as supp...

The residual dyes from different sources are considered a wide variety of organic pollutants introduced into the natural water resources. One of the main sources with severe pollution problems worldwide is the textile industry and its dye-containing wastewaters. The aim of this study was the photocatalytic degradation of the azoic dye “Orange II” u...

A series of low-loaded metallic-activated carbon catalysts were evaluated during the selective hydrogenation of a medium-chain alkyne under mild conditions. The catalysts and support were characterized by ICP, hydrogen chemisorption, Raman spectroscopy, temperature-programmed desorption (TPD), temperature-programmed reduction (TPR), X-ray diffracti...

Co3O4 particles were supported on a series of activated carbons (G60, CNR, RX3, and RB3). Incipient wetness method was used to prepare these catalysts. The effect of the structural and surface properties of the carbonaceous supports during oxidation of benzyl alcohol was evaluated. The synthetized catalysts were characterized via IR, TEM, TGA/MS, X...

Two composite supports with a mixed inorganic–organic structure were synthesized: BTAl and UTAl. Hydrophilic–hydrophobic dual properties of the supports were suitable for preparing egg-shell-supported metal catalysts for selective hydrogenation reactions. The catalysts were characterized by ICP, XRD, OM, TEM, EPMA, XPS and TGA. Their mechanical res...

This is a study on the kinetics of the liquid-phase hydrogenation of styrene to ethylbenzene over a catalyst of palladium supported on an inorganic– organic composite. This support has a better mechanical resistance than other commercial supports, e.g. alumina, and yields catalysts with egg-shell structure and a very thin active Pd layer. Catalytic...

Self-assembled monolayers (SAMs) are highly promising materials for molecular engineering of elec-tronic and spintronics devices thanks to their surface functionalization properties. In this direction,alkylphosphonic acids have been used to functionalize the most common ferromagnetic electrode inorganic spintronics: La2/3Sr1/3MnO3(LSMO). However, a...

Two series of ceria-promoted carbon-supported platinum catalysts have been prepared and evaluated in total oxidation of ethanol, as a model volatile organic compound (VOC), in order to study the effect of the metal precursor (H2PtCl6 or Pt(NH3)4(NO3)2) on their physico-chemical properties and catalytic behavior. Catalysts with Pt loading of 1 wt.%...

A series of CeO2–Nb2O5 mixed oxides with different Nb content, as well as the pure oxides, have been synthesized by co-precipitation with excess urea. These materials have been used as supports for platinum catalysts, with [Pt(NH3)4](NO3)2 as precursor. Both supports and catalysts have been characterized by several techniques: N2 physisorption at 7...

Catalysts consisting in platinum supported on cerium oxide highly dispersed on activated carbon, with a Pt loading of 1 wt.% and ceria loadings of 5, 10 and 20 wt.% have been prepared by impregnation method and characterized by several techniques (N2 adsorption at 77 K, ICP, XRD, H2-TPR and XPS). Their catalytic behavior has been evaluated in the t...

Low-cost tungsten monometallic catalysts containing variable amounts of metal (4.5, 7.1 and 8.5%W) were prepared by impregnating alumina with ammonium metatungstate as an inexpensive precursor. The catalysts were characterized using ICP, XPS, XRD, TPR and hydrogen chemisorption. These techniques revealed mainly WO3-Al2O3 (W6+) species on the surfac...

The effect of the metal precursor (presence or absence of chlorine) on the preferential oxidation of CO in the presence of H2 over Pt/CeO2 catalysts has been studied. The catalysts are prepared using (Pt(NH3)4)(NO3)2 and H2PtCl6, as precursors, in order to ascertain the effect of the chlorine species on the chemical properties of the support and on...

Herein, the preferential oxidation of CO in excess hydrogen (PROX reaction) was studied over Au catalysts supported on ceria and Y or Nb doped ceria. Both supports and catalysts have been extensively characterized by a number of advanced techniques; XRD, N2-adsortion, Raman spectroscopy, XPS, and H2-TPR. The catalytic results showed that when an id...

The hybrid structure of Fe2O3 nanoparticles/TiO2 nanofibers (NFs), combines the merits of large surface areas of TiO2 NFs and absorption in ultraviolet light–visible light range. This structure can be used for many applications such as photoelectrochemical water splitting and photo-catalysis. Here, a sol-flame method is used for depositing Fe2O3 on...

The sulfur resistance of low-loaded monometallic Pt catalysts and bimetallic Pt-W catalysts during the partial selective hydrogenation of styrene, a model compound of Pygas streams, was studied. The effect of metal impregnation sequence on the activity and selectivity was also evaluated. Catalysts were characterized by ICP, TPR, XRD, and XPS techni...

Palladium, platinum, and ruthenium supported on activated carbon were used as catalysts for the selective hydrogenation of 1-heptyne, a terminal alkyne. All catalysts were characterized by temperature programmed reduction, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. TPR and XPS suggest that the metal i...

Analyses of samples with iron sulfides are performed through micro X-ray fluorescence (μXRF) and X-ray photoelectron spectroscopy (XPS) in order to evaluate the possibilities offered by those techniques in the characterisation and quantification of iron sulfides contained in the aggregates used in concretes pursuant to the American standard ASTM_C_...

Partial hydrogenation of alkynes has industrial and academic relevance on a large scale, especially those with high selectivities. To increase the activity, selectivity and lifetime of low-loaded Pd monometallic catalyst, the development of bimetallic systems has been investigated. In this work Pd mono (Pd/A) and bimetallic catalysts (PdNi/A and WP...

Ce–Pr mixed oxides, namely Ce0.8Pr0.2O2, Ce0.5Pr0.5O2 and Ce0.2Pr0.8O2, were prepared by conventional coprecipitation and evaluated for the catalytic combustion of 1,2-dichloroethane, which was selected as a model reaction for chlorinated VOC abatement. For comparison purposes, the pure oxides were also prepared and catalytically tested. A certain...

In order to increase the production of olefins the partial hydrogenation of alkynes has achieved industrial importance. In this sense catalysts with selective hydrogenation properties may be of potential interest. In this work mono and bimetallic Pd and W catalysts supported on γ-alumina with low metal content (2.4% W and 0.4% Pd) were prepared. XP...

The poisoning resistance to sulfided and oxygenated compounds of some VIII Group PYGAS selective hydrogenation catalysts based on metals was assessed. Low content alumina supported Rh, Pd, Ru and Pt catalysts (0.35 wt%) were prepared from chlorided precursors. In the case of the palladium catalysts a nitrogenated precursor was also used. The cataly...

Recebido em 27/4/09; aceito em 30/10/09; publicado na web em 12/3/10 Semi-hydrogenation of alkynes has industrial and academic relevance on a large scale. To increase the activity, selectivity and lifetime of monometallic catalysts, the development of bimetallic catalysts has been investigated. 1-Heptyne hydrogenation over low-loaded Pd and Ni mono...

A series of Group VIII metal catalysts was obtained for the semi-hydrogenation of styrene. Catalysts were characterized by Hydrogen Chemisorption, TPR and XPS. Palladium, rhodium and platinum low metal loading prepared catalysts presented high activity and selectivity (ca. 98%) during the semi-hydrogenation of styrene, being palladium the most acti...

This paper reports a study of PtSn/TiO2 catalysts reduced at two different temperatures (473 and 773K) by infrared spectroscopy of CO adsorbed at 298K and XPS, as well as their behaviour in the vapour phase selective hydrogenation of crotonaldehyde at 333K. Catalysts with 2wt% Pt and different Pt:Sn atomic ratios were prepared by co-impregnation of...

The 1-heptyne selective hydrogenation carried out at 150 kPa, and at 283 and 303 K using Ru/Al2O3 and Ru/C as catalysts, was studied. Catalysts were prepared by the incipient wetness impregnation technique using RuCl3 as precursor. Ru/Al2O3 was treated in hydrogen at 373 or 573 K and Ru/C only at the last temperature. Catalysts were characterized b...

The effect of the reduction temperature has been studied on ceria-supported bimetallic platinum–zinc catalysts prepared from H2PtCl6 and Pt(NH3)4(NO3)2 as the platinum precursors and Zn(NO3)2 as the zinc precursor. The catalysts have been characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), and X-ray photoelectron spect...

The effect of the support on the liquid phase selective hydrogenation of benzene to cyclohexene over Ru catalysts was studied. Catalysts were prepared using RuCl3 as precursor and characterized by hydrogen chemisorption, XPS and TPR. The reaction was carried out at 373 K and 2 MPa using a stirred tank reactor. It was found that the catalytic activi...

Ruthenium (5%) on alumina was prepared by the incipient wetness impregnation technique using ruthenium chloride as precursor and reduced at two temperatures: 373 or 573 K. The catalytic behavior during the selective hydrogenation of 1-heptyne to 1-heptene was studied at 303 K, 750 rpm and at a hydrogen pressure of 150 KPa in a stirred tank reactor....

Ru/Al2O3 catalysts with different chlorine contents were prepared using RuCh as the precursor. Different HCl concentrations in the impregnation solution or different treatments after impregnation were used. The catalysts were characterized by temperature-programmed reduction, X-ray photoelectron spectroscopy, and hydrogen chemisorption. They were t...

The properties of Ru/Al2O3 catalysts prepared using RuCl3 as precursor and subjected to different treatments after impregnation, were studied using different techniques: XPS, FTIR, hydrogen chemisorption and thermal programmed reduction. Differences in the Ru species (Ru0, ruthenium oxides and ruthenium oxychloride), metal dispersion and chlorine c...

Sulfated silica–zirconia mixed oxides containing 33 mol% Zr were prepared by sol-gel routes with the sulfate/zirconia molar ratio varying between 0.2 : 1 and 0.3 : 1. The influence of the added sulfate introduced by both in situ and ex situ methods on the bulk and surface properties was examined and in particular the role of sulfate in modifying th...

Oxygen and nitrogen complexes formation in coal char due to its reaction with NO at 100 °C in presence or absence of O2 and/or H2O was studied by XPS. Formation of NO2 and pyridinic complexes and a considerable increment of oxygen complex was observed. The NO2 complexes can be formed in all cases, even when there is no molecular oxygen present in...

Increasing reduction time increases ruthenium reduction, but even after 6 h, ruthenium is not completely reduced and chlorine is not completely eliminated in Ru/Al2O3 prepared from RuCl3.

This chapter examines the effect of the zinc (Zn) content and the reduction temperature on the characteristics and catalytic properties of bimetallic platinum (Pt)–Zn catalysts supported on zeolite NaX. Catalysts have been characterized by temperature-programmed reduction (TPR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). T...

Infrared spectra of adsorbed CO have been used to monitor the surface of Cu/TiO2 which had been reduced in H2 at 523, 623 or 723 K and was also exposed to propene, butanal or crotonaldehyde. For CO alone infrared bands at 2118–2133 cm−1 dominated the spectra and are ascribed to CO interacting with Cu(I) sites in chains or two-dimensional rafts of C...

Activated carbon-supported cerium dioxide (CeO2/C) has been prepared by impregnation of the support with a solution of cerium (III) nitrate and further decomposition in helium. Then, platinum has been deposited on CeO2/C by impregnation with solutions containing H2PtC16 or [Pt(NH3)4](NO3)2. Sample characterisation has been carried out by thermograv...

XPS, temperature programmed reduction (TPR) and FTIR spectroscopy of adsorbed CO and the hydrogenation of crotonaldehyde were used to study the nature of the surface species present for two Cu–TiO2 catalysts (2 and 5% Cu) subjected to reduction in hydrogen at 523, 623 and 723 K. Despite TPR and XPS evidence for complete reduction, IR studies gave c...

Alumina- and silica-supported bimetallic Pt–Sn catalysts with different Pt/Sn atomic ratios have been prepared by using the bimetallic complex cis-[PtCl(SnCl3)(PPh3)2], the monometallic complex cis-[PtCl2(PPh3)2] and SnCl2 as metal precursors. Catalysts have been characterised by X-ray diffraction and transmission electron microscopy techniques, in...

The hydroformylation of styrene over Rh/SiO2·Al2O3 has been studied in the presence of the chiral diphosphines (−)-Chiraphos and (−)-DIOP. FTIR studies of the solid–liquid interface show that these molecules react with the surface rhodium gem-dicarbonyl complex to yield Rh(I)(CO)(P–P), which remains attached to the solid. FTIR and 31P CP MAS NMR me...

The presence of residual silicon in RBSC pieces reduces their mechanical properties at temperatures higher than 1300 ºC (mp of Si = 1410 ºC). This work presents the study of the substitution of silicon by a refractory silicide (W,MoSi2). The preparation variables have been the carbon source (activated carbon, graphite and coke), the particle size a...

This paper reports a study on the formation of tungsten and molybdenum silicides by displacement reaction between Si-WC, and Si-Mo2C respectively at temperatures ranging from 1300°C to 1900°C. The preparation variables have been the ratio metallic carbide to silicon ratio in order to control the type of silicide formed, and the W/Mo ratio, in order...

The effect of a previous oxidation treatment of the carbonaceous support on the catalytic behavior of platinum in the gas phase hydrogenation of crotonaldehyde (trans-2-butenal) over Pt/carbon black catalysts has been analyzed. Two heat-treated carbon blacks, one of them subjected to an oxidizing treatment with hydrogen peroxide, have been used as...

Two heat-treated carbon blacks, one of them subjected to an oxidizing treatment with hydrogen peroxide, have been used as supports for platinum, which has been introduced using both H2PtCl6 in acid media and [Pt(NH3)4]Cl2 in basic media. The catalysts have been characterized by H2 chemisorption at room temperature (after different pre-treatments),...

The platinum-ceria interaction, induced after high temperature reduction of platinum based catalysts, has been used to improve the selectivity towards crotyl alcohol in the gas phase hydrogenation of crotonaldehyde. Three catalysts have been used in this study, Pt/SiO2, Pt/CeO2, and Pt/CeO2/SiO2. They have been characterized by X-ray diffraction an...

A Pt/TiO2 catalyst has been subjected to reduction in hydrogen at 473, 573 and 773 K and the various degrees of metal-support interaction (SMSI) confirmed by means of CO and H2 chemisorption, FTIR of CO and the hydrogenation of crotonaldehyde. Coadsorption of CO and crotonaldehyde were performed to identify the preferred adsorption site and mode of...

Three activated carbons were prepared with different content of oxygen surface complexes and impregnated with aqueous solutions of [Pt(NH34]Cl2. The catalysts were characterized by H2 and CO chemisorption at room temperature, temperature-programmed decomposition (TPD) and X-ray photoelectron spectroscopy, and their catalytic behavior in the vapor p...

The effect of the preparation method on the catalytic behavior of bimetallic PtSnC catalysts in the vapor phase hydrogenation of crotonaldehyde has been determined. Nine PtSnC bimetallic catalysts have been prepared by coimpregnation and by successive impregnations of the support with solutions of the metal precursors, with SnPt atomic ratios ran...

Three bimetallic PtSn/C catalysts have been prepared by successive impregnation of pregraphitized carbon black with an aqueous solutions of hexachloroplatinic acid and tin(II) chloride. One monometallic Pt/C sample was also prepared and studied for comparison. All catalysts were characterized by hydrogen and carbon monoxide chemisorption at room t...

The effect of the degree of graphitization of the support on the dispersion, sintering resistance, and catalytic activity of a series of platinum catalysts supported on heat-treated carbon blacks has been determined. The supports were prepared by heat treatment of a furnace carbon black in an inert atmosphere at temperatures up to 2473 K. The resul...

Pt/activated carbon catalysts were prepared by using [Pt(NH3)4]Cl2 as the metal precursor, and characterized by a number of techniques. The selectivity of these catalysts towards crotyl alcohol in the gas-phase hydrogenation of crotonaldehyde was considerably increased when the activated carbon support was slightly oxidized before the metal incorpo...

Three samples of pregraphitized carbon blacks with the same porous texture but increasing amounts of oxygen surface groups have been used to prepare carbon-supported platinum catalysts (about 1 wt % loading). The carbon surface becomes oxidized upon impregnation with hexachloroplatinic acid in aqueous solution, whereas platinum is reduced from Pt(I...

Increasing heat treatment in He (up to 2200 °C) of a carbon black results in supports which after impregnation with H2PtCl6 produce catalysts with very high Pt dispersion (up to 0.99). The evolution in Pt dispersion and sintering resistence (in an H2 atmosphere up to 500°C and for up to 84h) has been explained in terms of the evolution of crystal s...

Increasing heat treatment in He (up to 2200ºC) of a carbon black results in supports which after impregnation with H2PtCl6 produce catalysts with very high Pt dispersion (up to 0.99). The evolution in Pt dispersion and sintering resistence (in an H2 atmosphere up to 500ºC and for up to 84h) has been explained in terms of evolution of crystal size a...

Increasing heat treatment in He (up to 2200ºC) of a carbon black results in supports which after impregantion with H2PtCl6 produce catalysts with very high Pt dispersion (up to 0.99). The evolution in Pt dispersion and sintering resistence (in an H2 atmosphere up to 500ºC and for up to 84 h) has been explained in terms of evolution of crystal size...