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In this work, bimetallic Cu–Ni catalysts have been studied in the water-gas shift (WGS) reaction, and they have shown different levels of synergy and anti-synergy in terms of catalytic activity and selectivity to the desired products. Cu–Ni interactions alter the physicochemical properties of the prepared materials (i.e. surface chemistry, redox behaviour, etc.) and as a result, the catalytic trends are influenced by the catalysts' composition. Our study reveals that Cu enhances Ni selectivity to CO2 and H2 by preventing CO/CO2 methanation, while Ni does not help to improve Cu catalytic performance by any means. Indeed, the monometallic Cu formulation has shown the best results in this study, yielding high levels of reactants conversion and excellent long-term stability. Interestingly, for medium-high temperatures, the bimetallic 1Cu–1Ni outperforms the stability levels reached with the monometallic formulation and becomes an interesting choice even when start-up/shutdowns operations are considered during the catalytic experiments. Financial support for this work was provided by the EPSRC grants EP/J020184/2 and EP/R512904/1 as well as the Royal Society Research Grant RSGR1180353. The Spanish team acknowledges Ministerio de Economía, Industria y Competitividad of Spain (Project MAT2013-45008-P). L. Pastor-Perez acknowledges Generalitat Valenciana for her postdoctoral grant (APOSTD/2017). Sasol is kindly acknowledged for providing the support.

CO2 utilisation is becoming an appealing topic in catalysis science due to the urgent need to deal with greenhouse gases (GHG) emissions. Herein, the dry reforming of methane (DRM) represents a viable route to convert CO2 and CH4 (two of the major GHG) into syngas, a highly valuable intermediate in chemical synthesis. Nickel-based catalysts are economically viable materials for this reaction, however they show inevitable signs of deactivation. In this work stabilisation of Ni in a pyrochlore-perovskite structure is reported as a viable method to prevent fast deactivation. Substitution of Zirconium by Ni at various loadings in the lanthanum zirconate pyrochlore La2Zr2O7 is investigated in terms of reactant conversions under various reaction conditions (temperature and space velocity). XRD analysis of the calcined and reduced catalysts showed the formation of crystalline phases corresponding to the pyrochlore structure La2Zr2-xNixO7-δ and an additional La2NiZrO6 perovskite phase at high Ni loadings. Carbon formation is limited using this formulation strategy and, as a consequence, our best catalyst shows excellent activity for DRM at temperatures as low as 600 °C and displays great stability over 350 h of continuous operation. Exsolution of Ni from the oxide structure, leading to small and well dispersed Ni clusters, could explain the enhanced performance. Financial support for this work was provided by the Department of Chemical and Process Engineering of the University of Surrey and the EPSRC grants EP/J020184/2 and EP/R512904/1 as well as the Royal Society Research Grant RSGR1180353. Authors would also like to acknowledge the Ministerio de Economía, Industria y Competitividad of Spain (Project MAT2013-45008-P).

Herein, we have studied an alternative route for preparing CuOx/CeO2 catalysts using metal organic frameworks (MOFs) as precursors. Usually, CuOx/CeO2 materials are prepared by wet impregnation of ceria support. In this study, we have impregnated a Cu-MOF with a ceria precursor and then pyrolized the impregnated MOF using different conditions and procedures. The prepared catalysts have been characterized by using a wide range of techniques such as XRD, XPS, Raman, and TPR. We have found that the pyrolysis method determines the dispersion of the oxidized copper species on the ceria surface what, in turn, controls the catalytic activity and selectivity of the catalysts in the reverse water-gas shift (RWGS) reaction. We have compared the behavior of the MOF-derived catalysts against an optimized catalyst prepared by a conventional method (wet impregnation), finding that the MOF-derived catalyst shows better catalytic performance. Financial support from Generalitat Valenciana (project PROMETEOII/2014/004) and MINECO (Project MAT2013-45008-P) is gratefully acknowledged. EVRF also thanks MINECO for his Ramon y Cajal fellow RYC-2012-11427 and the following project MAT2016-81732-ERC.

Three different conducting polymers, polythiophene (PT), polypirrol (PPY) and polyaniline (PANI) have been synthesized via oxidative chemical polymerization in aqueous media, in such a way that the synthesis protocol did not involve any toxic solvents. They have been tested in the abatement of nitrates from an aqueous solution without the need of any metal catalyst. The N-containing polymers (PANI and PPy) were able to remove nitrates to a level that accomplishes the European legislation requirements; however, the nature of each polymer greatly influenced the process mechanism. Whereas ion exchange between Cl- and SO42- counter-ions in the polymer and NO3- from water is the main responsible for the effective nitrate removal in PANI, as assessed by FTIR and XPS analyses, the nitrate removal mechanism on PPy is based in an electron transfer from the polymer to nitrate through N sites located in the pyrrolic ring. On the other hand, PT was not able to exchange nitrate unless it was synthesized with FeCl3 as oxidant/dopant and an anionic surfactant (sodium dodecyl sulfate -SDS-) is used. In that case, the electrostatic attraction between sulfate (OSO3-) groups from the surfactant and Fe3+ ions from FeCl3 produced the anchoring of Cl- to the oxidized PT growing chain, this favoring ion exchange with nitrate in the aqueous solution, followed by a redox process. Financial support from Generalitat Valenciana, Spain (PROMETEOII/2014/004) is gratefully acknowledged.

Commercial carbon nanotubes have been oxidized with HNO3, H2O2 and air and they have been tested on the cyclization of citronellal. The materials have been characterized by N2 adsorption/desorption isotherms, transmission electron microscopy, X-ray diffraction, temperature programmed desorption, potentiometry titration and X-ray photoelectron spectroscopy. The HNO3-treated samples displayed the largest concentration of carboxylic acids which increased by increasing the oxidation time and by a previous ball-milling treatment. The carboxylic acid groups were found to be the active groups on the reaction and the activity increased by increasing its content. The selectivity to isopulegols was higher (98%) over the most active samples (activity 0.20–0.68 mmol/g min), which has been explained by their smaller pore size caused by the oxidation treatment. The stability of the most active CNT sample was also proved by recycling the catalyst in 3 cycles. Financial support for the present study was received from CON-ICYT Chile, project 3130483 (Postdoctoral), Generalitat Valenciana, Spain (PROMETEOII/2014/004) is also gratefully acknowledged.

The low temperature water-gas shift (WGS) reaction has been studied over two commercial multiwall carbon nanotubes-supported nickel catalysts promoted by ceria. For comparison purposes, activated carbon-supported catalysts have also been studied. The catalytic performance and the characterization by N2 adsorption analysis, powder X-ray diffraction (XRD), temperature-programmed reduction with H2 (TPR-H2), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis showed that the surface chemistry has an important effect on the dispersion of ceria. As a result, ceria was successfully dispersed over the carbon nanotubes (CNTs) with less graphitic character, and the catalyst afforded better activity in WGS than the catalyst prepared over massive ceria. Moreover, a 20 wt.% CeO2 loading over this support was more active than the analogous catalyst with a 40 wt.% loading. The ceria nanoparticles were smaller when the support was previously oxidized, however this resulted in a decrease of the activity. Financial support from CONICYT (Chile, Postdoc FONDECYT 3130483), Ministerio de Economía y Competitividad (Spain, MAT2010-21147 and MAT2013-45008-P) and Generalitat Valenciana (Spain, PROMETEOII/2014/004) is gratefully acknowledged.

Pd nanoparticles have been synthesized over carbon nanotubes (CNT) and graphite oxide (GO) by reduction with ethylene glycol and by conventional impregnation method. The catalysts were tested on the chemoselective hydrogenation of p-chloronitrobenzene and the effect of the synthesis method and surface chemistry on their catalytic performance was evaluated. The catalysts were characterized by N2 adsorption/desorption isotherms at 77 K, TEM, powder X-ray diffraction, thermogravimetry, infrared and X-ray photoelectron spectroscopy and ICP-OES. It was observed that the synthesis of Pd nanoparticles employing ethylene glycol resulted in metallic palladium particles of smaller size compared to those prepared by the impregnation method and similar for both supports. The presence of oxygen groups on the support surface favored the activity and diminished the selectivity. It seems that ethylene glycol reacted with the surface groups of GO, this favoring the selectivity. The activity was higher over the CNT-based catalysts and both catalysts prepared by reduction in ethylene glycol were quite stable upon recycling. Financial support for the present study was received from CON-ICYT Chile, project 3130483 (Postdoctoral), Generalitat Valenciana, Spain (PROMETEOII/2014/004) is also gratefully acknowledged.

The RWGS reaction represents a direct approach for gas-phase CO2 upgrading. This work showcases the efficiency of Fe/CeO2-Al2O3 catalysts for this process, and the effect of selected transition metal promoters such as Cu, Ni and Mo. Our results demonstrated that both Ni and Cu remarkably improved the performance of the monometallic Fe-catalyst. The competition Reverse Water-Gas Shift (RWGS) reaction/CO2 methanation reaction was evident particularly for the Ni-catalyst, which displayed high selectivity to methane in the low-temperature range. Among the studied catalysts the Cu promoted sample represented the best choice, exhibiting the best activity/selectivity balance. In addition, the Cu-doped catalyst was very stable for long-term runs – an essential requisite for its implementation in flue gas upgrading units. This material can effectively catalyse the RWGS reaction at medium-low temperatures, providing the possibility to couple the RWGS reactor with a syngas conversion reaction. Such an integrated unit opens the horizons for a direct CO2 to fuels/chemicals approach. Financial support for this work was provided by the Department of Chemical and Process Engineering of the University of Surrey and the EPSRC grants EP/J020184/2 and EP/R512904/1 as well as the Royal Society Research Grant RSGR1180353. Authors would also like to acknowledge the Ministerio de Economía, Industrial Competitividad of Spain (Project MAT2016-80285-P). LPP also thanks Generalitat Valenciana for her postdoctoral fellow APOSTD2017.

A detailed study on the preparation of bimetallic PtSn/C catalysts using surfacecontrolled synthesis methods, and on their catalytic performance in the glycerol steam reforming reaction has been carried out. In order to obtain these well-defined bimetallic phases, techniques derived from Surface Organometallic Chemistry of Metals (SOMC/M) were used. The preparation process involved the reaction between an organometallic compound ((C4H9)4Sn) and a supported transition metal (Pt) in a H2 atmosphere. Catalysts with Sn/Pt atomic ratios of 0.2, 0.3, 0.5, and 0.7 were obtained, and characterized using several techniques: ICP, H2 chemisorption, TEM and XPS. These systems were tested in the glycerol steam reforming varying the reaction conditions (glycerol concentration and reaction temperature). The best performance was observed for the catalysts with the lowest tin contents (PtSn0.2/C and PtSn0.3/C). It was observed that the presence of tin increased the catalysts’ stability when working under more severe reaction conditions., Centro de Investigación y Desarrollo en Ciencias Aplicadas

The low temperature water–gas shift (WGS) reaction has been studied over Ni–CeO2/Graphene and Ni/Graphene. The catalysts were prepared with 5 wt.% Ni and 20 wt.% CeO2 loadings, by deposition-precipitation employing sodium hydroxide and urea as precipitating agents. The materials were characterized by TEM, powder X-ray diffraction, Raman spectroscopy, H2-temperature-programmed reduction and X-ray photoelectron spectroscopy (XPS). The characterization and the reaction results indicated that the interaction between the active species and the support is higher than with activated carbon, and this hinders the reducibility of ceria and thus the catalytic performance. On the other hand, the presence of residual sodium in samples prepared by precipitation with NaOH facilitated the reduction of ceria. The catalytic activity was highly improved in the presence of sodium, what can be explained on the basis of an associative reaction mechanism which is favored over Ni-O-Na entities. Authors thank to CONICYT (Chile, Postdoc FONDECYT 3130483) and Ministerio de Economía y Competitividad (Spain, MAT2010-21147 and MAT2013-45008-P) for financial support.

Copper-based catalysts supported on niobium-doped ceria have been prepared and tested in the preferential oxidation of CO in excess of H2 (PROX) and in total oxidation of toluene. Supports and catalysts have been characterized by several techniques: N2 adsorption, ICP-OES, XRF, XRD, Raman Spectroscopy, SEM, TEM, H2-TPR and XPS, and their catalytic performance has been measured in PROX, with an ideal gas mixture (CO, O2 and H2) with or without CO2 and H2O, and in total oxidation of toluene. The effects of the copper loading and the amount of niobium in the supports have been evaluated. Remarkably, the addition of niobia to the catalysts may improve the catalytic performance in total oxidation of toluene. It allows us to prepare cheaper catalysts (niobia it is far cheaper than ceria) with improved catalytic performance. The authors gratefully acknowledge the financial support from MINECO (Spain, Project MAT2010-21147)8/346) and Generalitat Valenciana (PROMETEOII/2014/004). EVRF thanks the MINECO for his Ramón y Cajal Fellow RYC-2012-11427. EOJ thanks the CNPq –Brazil for her grant.

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 total oxidation of ethanol and toluene after reduction at 473 K. The obtained results show that the prepared catalysts have better performances than platinum supported on bulk CeO2. The best catalytic performance was obtained for 10 wt.% ceria loading, likely due to an optimum synergistic interaction between highly dispersed cerium oxide and platinum particles. Pt-10Ce/C achieves total conversion of ethanol and toluene to CO2 at 433 K and 453 K, respectively, and shows no deactivation during a test for 100 h. Under humid conditions (relative humidity, RH, of 40 and 80%), the activity was only slightly influenced due to the hydrophobic character of the activated carbon support, which prevents the adsorption of water. Financial support from Generalitat Valenciana (Spain, PROMETEO/2009/002-FEDER and PROMETEOII/2014/004) is gratefully acknowledged.

The low temperature water–gas shift (WGS) reaction has been studied over carbon-supported nickel catalysts promoted by ceria. To this end, cerium oxide has been dispersed (at different loadings: 10, 20, 30 and 40 wt.%) on the activated carbon surface with the aim of obtaining small ceria particles and a highly available surface area. Furthermore, carbon- and ceria-supported nickel catalysts have also been studied as references. A combination of N2 adsorption analysis, powder X-ray diffraction, temperature-programmed reduction with H2, X-ray photoelectron spectroscopy and TEM analysis were used to characterize the Ni–CeO2 interactions and the CeO2 dispersion over the activated carbon support. Catalysts were tested in the low temperature WGS reaction with two different feed gas mixtures: the idealized one (with only CO and H2O) and a slightly harder one (with CO, CO2, H2, and H2O). The obtained results show that there is a clear effect of the ceria loading on the catalytic activity. In both cases, catalysts with 20 and 10 wt.% CeO2 were the most active materials at low temperature. On the other hand, Ni/C shows a lower activity, this assessing the determinant role of ceria in this reaction. Methane, a product of side reactions, was observed in very low amounts, when CO2 and H2 were included in the WGS feed. Nevertheless, our data indicate that the methanation process is mainly due to CO2, and no CO consumption via methanation takes place at the relevant WGS temperatures. Finally, a stability test was carried out, obtaining CO conversions greater than 40% after 150 h of reaction. Financial support of Ministerio de Ciencia e Innovación of Spain (Project MAT2010-21147) is gratefully acknowledged. L.P.P. acknowledges her grant BES-2011-0406508.

The effect of the textural properties of a series of commercial carbon molecular sieves (CMS), prepared from different polymeric precursors, on their ability for CO2 adsorption at different temperatures has been studied. The adsorbents have been characterized by N2 and CO2 adsorption at 77 and 273 K, respectively, together with measurements of immersion calorimetry into liquids of different molecular dimensions. The studied CMSs cover a wide range of porosity, from purely microporous carbons to samples containing wide micropores as well as a certain proportion of mesoporosity. Studies of CO2 adsorption, at atmospheric pressure (1 bar) and three different temperatures (273, 298 and 323 K), have shown that a high CO2 adsorption capacity requires the presence of a well-developed microporosity, as well as a high volume of narrow micropores. On the other hand, narrow micropores seem to be the key factor leading to a maximum capacity of CO2 adsorption, even at temperatures close to that of anthropogenic emissions of CO2.

Ni-based catalysts supported on Zn-modified alumina were investigated in the ethanol steam reforming reaction. A commercial γ-alumina was impregnated with different amounts of zinc nitrate (0, 2, 5, 10, 15, 20 wt.% on Zn basis), calcined, and then impregnated with nickel nitrate aqueous solutions. The samples were characterized by a number of techniques: N(2) adsorption at 77 K, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray fluorescence (XRF), and temperature-programmed reduction (TPR). Their catalytic behavior in the ethanol steam reforming reaction was studied at 873 K, with a H(2)O/ethanol ratio of 5:1. Two effects of the presence of Zn were detected. On the one hand, zinc modifies the surface structure and the surface chemistry of the catalysts by formation of zinc aluminates, and on the other hand, zinc oxide can be reduced to metallic zinc under reaction conditions, thus modifying the catalytic properties of the active phase. The presence of Zn increases the ethanol conversion to gaseous compounds as compared with the catalyst supported on the Zn-free commercial alumina. The addition of a small amount of Pt (1 wt.%) causes a beneficial effect in the reaction. When Ni catalysts were used without a previous reduction treatment, ethylene was formed in high amounts; however, the Pt-Ni catalysts need no reduction pre-treatment to achieve high H(2) yields (close to 70%) and showed a high stability versus time on stream because of the control of the production of ethylene, a coke precursor.

The effect of the support (activated carbon or titanium dioxide) on the catalytic activity and selectivity to nitrogen of Pt-Sn catalysts in nitrate reduction was studied. The effects of the preparation conditions and the Pt:Sn atomic ratio were also evaluated. It was observed that the support plays an important role in nitrate reduction and that different preparation conditions lead to different catalytic activities and selectivities. Generally, the catalysts supported on activated carbon were less active but more selective to nitrogen than those supported on titanium dioxide. The monometallic Pt catalyst is active for nitrate reduction only when supported on titanium dioxide, which is explained by the involvement of the support in the reaction mechanism. The catalysts were characterized by different techniques, and significant changes on metal chemical states were observed for the different preparation conditions used. Only metallic Pt and oxidized Sn were observed at low calcination and reduction temperatures, but some metallic Sn was also present when high temperatures were used, being also possible the formation of Pt-Sn alloys.

Preferential oxidation of CO in excess hydrogen (PROX) was studied over Pt catalysts supported on multi-wall carbon nanotubes in the temperature range between room temperature and the temperature of the water–gas shift unit (∼473 K). Experimental results show that the Pt/CNT catalyst exhibit a superior performance in terms of catalytic activity and selectivity towards CO 2 formation compared to a Pt/AC catalyst prepared under similar conditions. Apparently, preferential CO oxidation in excess hydrogen over Pt nanoparticles supported on carbon materials is a particle size dependent reaction, i.e. larger particles exhibit higher activity and selectivity. In any case, the incorporation of oxygen functionalities to the carbon support becomes detrimental for the CO oxidation reaction independently of the carbon support used. Finally, CeO 2 addition to the Pt/CNT catalyst further improves both catalytic activity and selectivity at low temperatures (CO conversion rate of 46% at 313 K), the catalytic performance being superior to that exhibited by a traditional PROX catalyst such as Pt/CeO 2 .

Several catalysts of cerium oxide highly dispersed on activated carbon were prepared varying the cerium precursor, the solvent and the chemical surface properties of the support, and characterized by several techniques. Afterwards, these materials were investigated as ozonation catalysts for the mineralization of two organic compounds (oxalic acid and aniline). The ozonation results were compared with those obtained in the absence of catalyst and in the presence of the parent activated carbons used for the preparation of these materials. The prepared catalysts have better performances than the parent activated carbons, denoting a clear synergic effect between activated carbon and cerium oxide. The efficiency of the catalysts is mainly affected by the amount of Ce 3+ species on the surface. However, in the ozonation of oxalic acid, the specific surface area and metal oxide particle diameter also played an important role. The use of activated carbon as support favors the removal of both organic compounds studied. Highly dispersed cerium oxide on activated carbon shows better catalytic performance than a composite with the same composition.

The low temperature water gas shift reaction has been studied over carbon-supported platinum catalysts promoted by ceria. To this end, CeO2 has been dispersed over an activated carbon support at different loadings (20, 30 and 40 wt.%) in order to obtain a high ceria surface area. Then, platinum has been incorporated by impregnation with an acetone solution of [Pt(NH3)4](NO3)2. Two more catalysts have been prepared with aqueous and ethanolic solutions, respectively, to assess the effect of the solvent in the final catalysts. Pt/CeO2 and Pt/C catalysts have been used as references. Catalysts have been characterized (N2 adsorption at 77 K, TEM, H2-TPR) and tested in reaction after reduction with H2 at 473 K. The obtained results show that CO conversion increases with the amount of ceria loaded, from 20 to 40 wt.%. At this temperature, platinum supported on bulk CeO2 is less active than its carbon-based counterparts. The best results are obtained for the catalysts with 40 wt.% CeO2 prepared by aqueous impregnation of the platinum precursor, which achieves conversions higher than 70% at 573 K, and shows no deactivation under reaction at this temperature for 120 h. On the other hand, Pt/C shows a very low activity, this certifying the determinant role of ceria in this reaction. These results indicate that dispersion of ceria on activated carbon allows to obtain catalysts with superior performance than using bulk CeO2 as support, and with a lesser amount of ceria.

The grafting of natural halloysite nanotubes (HNT) with aminosilanes exhibiting two (DAS) and three (TAS) amino groups has been investigated and compared to the physisorption of both silanes on halloysite nanotubes. Halloysite nanotubes were used as solid support for the heterogeneous Atom Transfer Polymerization of methyl methacrylate (MMA) into poly(methylmethacrylate) (PMMA) using CuBr as catalyst. Silane grafted on the nanoclay acts both as a ligand that bonds to CuBr and as a catalyst for the heterogeneous MMA polymerization. Grafting of halloysite nanotubes with DAS produced a polymer with polydispersities similar to those produced by the physically adsorbed diaminosilane catalyst, but conversion percentages were lower and a poorer control over the polymerization reaction was achieved. Grafting of halloysite nanotubes with TAS had a detrimental effect on the control of the polymerization reaction and a loss of catalytic activity due to the immobilization of the copper catalyst. The best control over the polymerization of methyl methacrylate is achieved when the catalyst is not immobilized by covalent bond on the surface of halloysite nanotubes. Therefore, physysorption of the CuBr/aminosilane complex on the halloysite nanotubes provided better control on the polymerization reaction compared to the grafting of the aminosilanes on the halloysite nanotubes.

A parent activated carbon (C-0) was subjected to four different treatments: (i) heat treatment at 1273 K in Ar (C-1); (ii) heat treatment at 473 K in air (C-2); (iii) oxidation with H 2 O 2 (C-3) and, (iv) oxidation with HNO 3 (C-4). These materials were evaluated as supports of CuBr–[1,1,4,7,10,10-hexamethyltriethylenetetramine] (Cu I Br–HMTETA), a catalyst for the Atom Transfer Radical Polymerization (ATRP) of methyl methacrylate (MMA) using methyl-α-bromophenylacetate (MBP) as radical initiator. The supported catalysts showed an adequate control of polymerization, evidenced by polydispersity indexes (PDI) falling in the range 1.13–1.55. The best performance was achieved when activated carbon was treated with nitric acid (C-4) and with air at 473 K (C-2). Some copper leaching was always detected. The catalysts were reused and an adequate polymerization control was obtained in subsequent runs.

The influence of calcination and reduction temperatures on the catalytic properties of Pd–Cu and Pt–Cu bimetallic catalysts supported on activated carbon for the reduction of nitrates was studied. The catalysts were prepared using different calcination and reduction temperatures, and the respective activities and selectivities for the reduction of nitrates in water with hydrogen were assessed. It was found that the different preparation conditions lead to different catalytic performances. For both catalysts, the activity decreases by increasing calcination and reduction temperatures, whereas the effect on the selectivity is not uniform. For the 1%Pd–0.3%Cu (wt.%) catalyst, the nitrate conversion after 5 h of reaction varies from 93% (sample calcined at 200 °C and not reduced) to 25% (sample calcined and reduced at 400 °C). The formation of alloys during the preparation of the catalysts is prejudicial for nitrate reduction. In all the preparation conditions tested the Pd–Cu pair is more selective for the transformation of nitrate into nitrogen. All the samples have been characterized by nitrogen adsorption at −196 °C, CO adsorption microcalorimetry, TPR, XRD, XPS and TEM.

Three activated carbons exhibiting different textural characteristics were considered as support for CuBr–HMTETA catalyst in the Atom Transfer Radical Polymerization (ATRP) of methyl methacrylate. The pore distribution of the activated carbons played an important role in the control of the polymerization reaction: polydispersity index always failed in the range 1.1–1.3. However, the accessibility of the catalyst to pores in the activated carbon was limited by pore size and growing polymer size. Catalyst located within the micropores of spherical carbon was isolated from the growing polymer chains during the polymerization reaction, which took place at the mesopores. Mesoporous structure of LMA F-12 carbon enhanced polymerization rate but control over the molecular weight distribution was decreased. A carbon with an adequate distribution of micro- and mesoporosity (RGC-30) provided a suitable balance between activation and deactivation processes involving Cu (I) and Cu (II) catalytic species, which resulted in the appropriate control of the molecular weight during the methyl methacrylate polymerization reaction.

The effect of the ruthenium precursor (chlorinated or chlorine-free) on the properties and the catalytic behaviour of Ru/ZnO catalysts in the vapour phase hydrogenation of crotonaldehyde (2-butenal) has been studied. Two catalysts were prepared, using ruthenium (III) chloride (Ru(Cl)/ZnO) and ruthenium (III) acetylacetonate (Ru(A)/ZnO) as the metal precursors. The catalysts have been characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), H 2 temperature-programmed desorption (H 2 -TPD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM), and their catalytic behaviour has been evaluated in the title reaction after reduction at low (473 K) and high (623 K) temperatures. Ru(Cl)/ZnO showed better catalytic behaviour after both reduction treatments, what has been explained on the basis of a well controlled metal-support interaction. For Ru(A)/ZnO this interaction is too high, resulting in a dramatic lost of active sites that yields worse catalytic behaviour. It is important to remark that both catalysts were very active and selective to the desired product, the unsaturated alcohol (crotyl alcohol, 2-buten-1-ol).

A series of binderless activated carbon monoliths (ACMs) have been prepared from petroleum pitch and using KOH as activating agent. Characterization shows that these activated carbons combine a large “apparent” surface area (up to S BET ∼ 3000 m 2 /g) together with a well-developed narrow micropore size distribution. Dynamic column adsorption experiments using different volatile organic compounds (VOCs), ethanol and benzene, show that these activated carbons prepared from mesophase-based materials exhibit a superior saturation capacity compared to conventional carbon materials. The total amount adsorbed reaches values as high as 18 g/100 g AC and 40 g/100 g AC, for ethanol and benzene, respectively. These are the best results reported in the literature. The total amount adsorbed for both molecules correlates with the total volume of narrow micropores, thus confirming the pore size specificity required for the adsorption of VOC molecules. Regeneration studies show that ethanol can be easily desorbed at room temperature by flowing clean air through the adsorbent whereas benzene requires a further heating for complete desorption/regeneration.

Two series of activated carbons have been prepared from date pits; series C, using carbon dioxide as activating agent, and series S, prepared by activation with steam under the same experimental conditions. The obtained samples were oxidized with nitric acid in order to introduce more oxygen surface groups. The surface area and porosity of the parent and oxidized activated carbons were studied by N2 adsorption at 77 K and CO2 adsorption at 273 K. The oxygen surface complexes were characterized by temperature-programmed decomposition (TPD). The results show that carbon dioxide and steam activations produce microporous carbons with an increasing amount of CO evolving groups when increasing the burn-off. On the other hand, oxidation with nitric acid increases the amount of CO and CO2 evolved by the decomposition of surface oxygen groups, this increase being related to the development of porosity in the carbon with the degree of activation and to the activating agent used (CO2 versus steam).

Combined NMR cryoporometry, relaxometry and diffusometry were applied to characterize porous carbon materials. Pore space characterization in NMR cryoporometry is based on the measurement of melting point depression of the confined liquids, whereas NMR relaxometry and diffusometry explore the random motion of the molecules under confinement by the pore space. We demonstrate compatibility between the evidence of classical sorption experiments and NMR cryoporometry on pore size distribution. There is a distribution in both the nuclear magnetic relaxation rates and diffusion coefficients. These distributions have to be referred to heterogeneities in the pore space. Since they can only be observed if their influence is not averaged out on the diffusion paths covered by the molecules during the respective measurements, the spatial extension of the regions with structural differences (as evidenced by the differences in diffusion and nuclear magnetic relaxation of the probe molecules) may be estimated to be at least of the order of 20 μm.

The alkylation of imidazole (C 3 H 4 N 2 ) with different alkyl halides, such as 1-Br-butane, 2-Br-butane and 1-Br-hexane, has been carried out in the absence of solvent using basic zeolites as catalysts. Catalysts were prepared by cation exchange of a commercial NaX zeolite with different alkaline-earth cations (Ca, Sr and Ba). The resulting zeolites were characterised by N 2 (77 K) and CO 2 (273 K) adsorption, immersion calorimetry, CO 2 adsorption calorimetry and CO 2 temperature-programmed desorption experiments. The influence of the irradiation time and power and the alkaline-earth exchanged cation on the catalytic activity has been studied. Conversion values as high as 95% and selectivity values of 100% were obtained at 700 W in only 5 min in most of the cases when 1-Br-butane and 2-Br-butane were used as alkylating agents. In general, NaX is the best catalyst in most of the reaction conditions studied.

Activated carbons with increasing porosity have been prepared by chemical activation of olive stones using ZnCl2 followed by physical activation with CO2. The development of porosity and surface area with burn-off favours the adsorption capacity for ethanol. However, the total amount adsorbed (g/100 g AC) achieves a maximum for the sample with 30% burn-off, this amount decreasing thereafter. Apparently, for a low boiling point alcohol such as ethanol there is a critical pore size which allows an optimum packing of the adsorbed ethanol molecules. A further broadening of the porosity becomes detrimental due to the decreased overlapping adsorption potential inside the micropores. Incorporation of surface functionalities (oxygen surface groups) on the activated carbon enhances the adsorption capacity through the development of specific interactions between the ethanol molecule and the oxygen surface groups.

Nanotubes of natural halloysite (HNTs) were used as a solid support for the heterogeneous atom transfer polymerization of methyl methacrylate (MMA) into poly(methylmethacrylate) (PMMA) using adsorbed CuBr–[1,1,4,7,10,10-hexamethyltriethylenetetramine] (CuBr–HMTETA) and CuBr–[3-(2-aminoethylamino)propyltrimethoxysilane] (CuBr–AEAPTS) as catalysts. CuBr–AEAPTS supported on HNTs proved to mediate a living polymerization of MMA, demonstrated by (i) an increase in the number-average molecular weight (Mn) with the increase of conversion, (ii) relatively low polydispersity indexes (PDI), and (iii) linear first-order rate plots. The presence of HNTs had a strong effect on the polymerization rate.