Blasco Lanzuela, Teresa
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- PublicationA Multi-Nuclear MAS-NMR Study on the Structural Properties of Silicalite-1 Zeolite Synthesized Using N- and P-Based Organic Structure Directing Agents(MDPI AG, 2021-08) Martinez-Ortigosa, Joaquin; Simancas, Jorge; Vidal Moya, José Alejandro; Rey Garcia, Fernando; Valencia Valencia, Susana; Blasco Lanzuela, Teresa; Instituto Universitario Mixto de Tecnología Química; European Regional Development Fund; Ministerio de Economía y Competitividad; Ministerio de Ciencia, Innovación y Universidades; MINISTERIO DE ECONOMÍA, INDUSTRIA Y COMPETITIVIDAD[EN] The nature of organic structure directing agents (OSDAs) is of paramount importance in the final properties of zeolites, particularly the framework and porosity. Recently, the use of P-containing OSDAs has been employed for new zeolites, but there is little discussion compared to their analogues N-OSDAs. The main objective of this work is the characterization of pure silica MFI zeolite (silicalite-1) prepared by the dual-template route with tetrapropylammonium (TPA), tetrapropylphosphonium (TPP) cations, and mixtures thereof aiming to understand by advanced NMR methods how the nature of the organic influences the physico-chemical properties of the zeolite. Silicalite-1 has been successfully synthesized using the dual-template procedure with TPA and TPP molecules. Both OSDAs are incorporated into the zeolite without any specific preference, differently to that observed before for the TEA/TEP system, and homogenously mixed inside of the zeolite voids. The presence of TPP leads to the incorporation of less F, raising the concentration of Q(3)-defective sites in the silicalite-1 zeolites. Detailed NMR results indicate that those structural defects are close to the -CH3 group of the entrapped OSDAs in the zeolite and these defects consist of at least two silanol groups stabilizing the Si-O- species, which is responsible for the charge balancing.
- PublicationAgY zeolite as catalyst for the selective catalytic oxidation of NH3(Elsevier, 2021-08) Martinez-Ortigosa, Joaquin; Lopes, Christian W.; Agostini, Giovanni; Palomares Gimeno, Antonio Eduardo; Blasco Lanzuela, Teresa; Rey Garcia, Fernando; Departamento de Ingeniería Química y Nuclear; Instituto Universitario Mixto de Tecnología Química; Escuela Técnica Superior de Ingeniería Industrial; European Commission; Agencia Estatal de Investigación; Ministerio de Economía y Competitividad; Ministerio de Ciencia, Innovación y Universidades; Coordenaçao de Aperfeiçoamento de Pessoal de Nível Superior, Brasil[EN] Ag-exchanged Y zeolites (Si/Al = 2.5; Ag/Al = 0.30-0.95) have been tested in the NH3-SCO reaction, the most promising method for the elimination of ammonia emissions, and deeply characterized before and after reaction by using a variety of techniques (XRD, TEM, UV-Vis, Ag-109 NMR, XAS spectroscopies). The most active centres for the NH3-SCO reaction are Ag-0 nanoparticles (NPs) formed under reduction conditions and both activity and selectivity to N-2 increase with the silver loading. The Ag-0 NPs are dramatically modified under reaction conditions, being most of them dispersed resulting in small clusters and even atomically Ag+ cations, the latter accounting for around half silver atoms. The presence of water into the reaction feed promotes the dispersion and oxidation of silver nanoparticles, but the catalyst performance is only slightly affected. The results are fully consistent with the previously proposed i-SCR mechanism for NH3-SCO reaction on silver catalysts.
- PublicationModeling of EPR Parameters for Cu(II): Application to the Selective Reduction of NOx Catalyzed by Cu-Zeolites(Springer-Verlag, 2018-06) Fernández-Villanueva, Estefanía; Moreno González, Marta; Moliner Marin, Manuel; Blasco Lanzuela, Teresa; Boronat Zaragoza, Mercedes; Corma Canós, Avelino; Instituto Universitario Mixto de Tecnología Química; Ministerio de Economía y Competitividad; European Research Council[EN] We present a combined theoretical-experimental study aiming to provide information about the location and coordination environment of the Cu2+ species involved in the selective reduction of NOx with NH3 catalyzed by Cu-zeolites. From the experimental side, we show and discuss the EPR spectra of the three molecular sieves most widely used as catalysts for the NH3-SCR-NOx reaction, namely Cu-SSZ-13, Cu-SAPO-34 and Cu-ZSM-5 both in their hydrated state and after dehydration. Then, we investigate the EPR spectra of Cu-SSZ-13 and Cu-SAPO-34 under the following conditions: (i) after NH3 adsorption, (ii) after NO addition, and (iii) in the presence of a NO/O-2 mixture. As regards the theoretical part, an exhaustive computational study has been performed that includes geometry optimization and calculation of the EPR parameters of all the relevant systems involved in the NH3-SCR-NOx reaction. The influence of local geometry and Al/Si distribution in the zeolite framework on the EPR parameters and the most probable location of Cu2+ in each material are analyzed, and assignations of the EPR signals obtained under different reaction conditions are discussed.
- PublicationStudy of propane oxidation on Cu-zeolite catalysts by in-situ EPR and IR spectroscopies(Elsevier, 2014-05-15) Moreno González, Marta; Blasco Lanzuela, Teresa; Góra-Marek, Kinga; Palomares Gimeno, Antonio Eduardo; Corma Canós, Avelino; Departamento de Ingeniería Química y Nuclear; Instituto Universitario Mixto de Tecnología Química; Escuela Técnica Superior de Ingeniería Industrial; Ministerio de Ciencia e Innovación; Ministerio de Economía y CompetitividadThree Cu-zeolites with different structure, Cu-TNU-9, Cu-ITQ-2 and Cu Y have been tested as catalysts for propane oxidation reaction. The activity follows the trend: Cu-TNU-9 > Cu-ITQ-2 > Cu Y, and in situ electron paramagnetic resonance (EPR) and infrared (IR) spectroscopies have been used to ascertain the origin of their different behavior. The IR spectra show bands ascribed to the formation of COO− and CHO adsorbed on the Cu-zeolites as reaction intermediates in the oxidation of propane with an intensity that follows the same tendency that their oxidation activity. The EPR spectra of the three Cu-zeolites show that about 40 50% of total copper is present as isolated Cu2+ species, and heating under propane or propane oxygen mixture at 350 °C provokes the reduction of Cu2+ to Cu+ following the same trend that the oxidation activity, i.e., Cu-TNU-9 > Cu-ITQ-2 > Cu Y. Further analysis of the EPR spectra suggests that the reducibility of exchanged Cu2+ cations in the Cu-zeolites is determined by their accessibility to the propane molecules.
- PublicationOne-pot deposition of gold on hybrid TiO2 nanoparticles and catalytic application in the selective oxidation of benzyl alcohol(Elsevier, 2015-01-15) Mehri, Afef; Kochkar, Hafedh; Berhault, Gilles; Cómbita Merchán, Diego Fernando; Blasco Lanzuela, Teresa; Instituto Universitario Mixto de Tecnología Química; Universitat Politècnica de València[EN] One-pot deposition of Au onto TiO2 has been achieved through directly contacting gold (III) salt with nanosized functionalized TiO2 support initially obtained by sol-gel process using titanium isopropoxide and citric acid. Citrate groups act as functional moieties able to directly reduce the Au salt avoiding any further reducing treatment. Various gold salts (NaAuCl4 center dot 2H(2)O or HAuCl4 center dot 3H(2)O) and titanium to citrate (Ti/Cit) molar ratios (20, 50 and 100) were used in order to study the effect of the nature of the precursor and of the citrate content on the final Au particle size and catalytic properties of the as-obtained Au/TiO2 materials. Au/(TiO2)(x)(Cit)(1) catalysts characterization was performed using N-2 adsorption-desorption, ICP-AES, X-ray diffraction and TEM. The effect of the Ti/Cit molar ratio and of the gold precursor was evaluated. The selective oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) was studied as a model reaction. Kinetic analysis showed that the catalytic reaction rate was pseudo first-order and the values of activation energy have been reported. Results showed that the functionalization of TiO2 by citrate allows tuning the size of the Au nanoparticles deposited onto TiO2 as well as their morphology. Citrate also strongly enhances the benzyl alcohol oxidation through the control of the size and morphology of gold nanoparticles. (C) 2014 Elsevier B.V. All rights reserved.
- PublicationSilica supported copper and cerium oxide catalysts for ethyl acetate oxidation(Elsevier, 2013-08-15) Tsoncheva, Tanya; Issa, Gloria; Blasco Lanzuela, Teresa; Concepción Heydorn, Patricia; Dimitrov, Momtchil; Hernández Morejudo, Selene; Kovacheva, Daniela; Atanasova, Genoveva; López Nieto, José Manuel; Instituto Universitario Mixto de Tecnología Química; Ministry of Education and Science, Bulgaria; Ministerio de Economía y Competitividad[EN] The formation of active sites in the silica supported copper and cerium oxide hi-component catalysts for total oxidation of ethyl acetate was studied by Nitrogen physisorption, XRD, XPS, UV-Vis, Raman, FTIR of adsorbed CO spectroscopies and TPR. It was found that the interaction between the copper oxide nano-particles and the supported on the silica ceria ones is realized with the formation of interface layer of penetrated into ceria lattice copper ions in different oxidative state. This type of interaction improves the dispersion of copper oxide particles and provides higher accessibility of the reactants to the copper active sites even at low copper amount. (C) 2013 Elsevier Inc. All rights reserved.
- PublicationEffect of zeolite structure on the selective catalytic reduction of NO with ammonia over Mn-Fe supported on ZSM-5, BEA, MOR and FER(Springer-Verlag, 2021-05) Ben-Younes, Nada; Martinez-Ortigosa, Joaquin; Marie, Olivier; Blasco Lanzuela, Teresa; Mhamdi, Mourad; Instituto Universitario Mixto de Tecnología Química; Agencia Estatal de Investigación; Ministerio de Economía y Competitividad; Ministerio de Economía, Industria y Competitividad[EN] A series of catalysts based on Mn-Fe loaded zeolites was prepared by impregnation and their activity in the selective catalytic reduction of NO with ammonia (NH3-SCR) was investigated. The highest catalytic conversion was recorded for MnFe-ZSM-5 (MnFe-Z), followed by MnFe-BEA (MnFe-B) and MnFe-MOR (MnFe-M), while MnFe-FER (MnFe-F) showed a very poor activity over the entire temperature range. In order to evidence a correlation between the structure and acidity of the zeolites and NO conversion, the prepared samples were characterized by various techniques (ICP-AES, N-2 physisorption at 77 K, XRD, (NMR)-N-27, Raman, FTIR spectroscopy of adsorbed ammonia, H-2-TPR, DRS UV-Vis, EPR and XPS). The superior catalytic activity of MnFe-Z at low temperature is attributed to the abundance of Mn4+ concentration as revealed by XPS, the highest NH3-L/NH4+ ratio indicative of the contribution of metals in generating Lewis acidic centers as evidenced by IR-NH3, and the better reducibility of manganese and iron on ZSM-5 which increases the kinetics for red-ox cycles as confirmed in TPR analysis. Fe3Mn3O8 mixed oxide phase is also detected by XRD and XPS and can be associated with the high reducibility of MnFe-Z which generates a high oxidation ability favoring NO to NO2 oxidation. Raman spectroscopy was also used to confirm the existence of a strong synergy between metals and ZSM-5 support revealed by the shift in the signal position and the decrease in band intensities. The results showed that the zeolite framework and acidity generate catalysts with different textural and structural properties which influence the metal dispersion and speciation and hence influence the catalytic performances.
- PublicationStructural Characterization of Zeolites by Advanced Solid State NMR Spectroscopic Methods(Academic Press, 2012) Mafra, Luis; Vidal Moya, José Alejandro; Blasco Lanzuela, Teresa; Instituto Universitario Mixto de Tecnología Química; Generalitat Valenciana; Ministerio de Ciencia e Innovación; Ministerio de Economía y Competitividad; Fundação para a Ciência e a Tecnologia, Portugal; European Commission[EN] This review overviews the application of solid state NMR spectroscopy to the structural characterization of silicate, and acidic aluminosilicate and borosilicate zeolites focusing on the utilization of new developed methods. We summarize recent results on the investigations of the distribution of silicon atoms into the zeolite framework, as well as the location of F¿ anions and formation of pentacoordinated silicon species in zeolites synthesized in fluoride medium. Special attention is paid here to the characterization of framework and extraframework boron and most specially aluminium species and the acid sites in zeolites. In Section 6 of this review, we present the basis and practical aspects of advanced NMR experiments used in the characterization of microporous solids paying special attention to quadrupolar nuclei and other methods based on dipolar interactions.
- PublicationAlkali poisoning of Fe-Cu-ZSM-5 catalyst for the selective catalytic reduction of NO with NH3(Springer-Verlag, 2022-08) Jouini, Houda; Mejri, Imène; Martinez-Ortigosa, Joaquin; Cerrillo, Jose L.; Petitto, Carolina; Mhamdi, Mourad; Blasco Lanzuela, Teresa; Delahay, Gérard; Instituto Universitario Mixto de Tecnología Química[EN] Fe (2 wt%)-Cu (1.5 wt%)-ZSM-5 SCR catalyst contacted 1.5 wt% of Na and 1.8 wt% of K in order to simulate poisoning by species more specifically contained in exhaust gases from exhaust gases of diesel engines and power plants. Poisoning agents do not cause loss of surface area nor pore occlusion. XRD and SEM results showed that alkali metals introduction did not deteriorate the crystallinity and morphology of zeolite crystals. However, a significant loss of surface acidity was observed upon alkali-poisoned catalysts causing a dramatic deactivation of the NH3-SCR of NO reaction. Na-doped catalyst showed higher low-temperature SCR activity, while potassium has a stronger deactivation effect on Fe-Cu-ZSM-5 than sodium beyond 400 degrees C.
- PublicationElectrical conductivity of a MoVTeNbO catalyst in propene oxidation measured in operando conditions(Elsevier, 2010-10-15) Caldararu, M.; Scurtu, M.; Hornoiu, C.; Munteanu, C.; Blasco Lanzuela, Teresa; López Nieto, José Manuel; Instituto Universitario Mixto de Tecnología Química; Ministerio de Educación y Ciencia[EN] A complex ac electrical conductivity study was performed on a Te(0.33)MO(3.33) (M = Mo + V + Nb) pure phase (M2-type phase) in operando conditions, using the differential step technique (DST). The aim is to obtain new information about the influence of the oxidation and moisture on the catalytic behaviour of this phase in propene oxidation to acrylic acid. Three successive series of experiments were performed on the same batch of sample: (i) cycles of heating (up to 300, 350 and 400 degrees C, respectively)-cooling (to room temperature) in inert and in the catalytic test mixture, without intermediate oxidation; (ii) the same, but intercalating heating-cooling oxidation cycles (up to 300, 350 and 400 degrees C, respectively) before the corresponding catalytic test runs; and (iii) catalytic testing runs performed by heating up to 400 degrees C in the presence of pre-absorbed or co-adsorbed humidity. Based on the electrical conductivity results, it appears that 350 degrees C is a critical temperature in terms of surface reduction/re-oxidation: below this temperature no major surface changes of the relative oxidation level occur on flushing in dry helium or in the catalytic test mixture, while above it, an important reduction occurs in the same atmospheres. Re-oxidation in oxygen is not efficient if performed below 350 degrees C, but if done above (up to 400 degrees C) the surface recovers almost the initial behaviour. These results suggest the reversibility of the oxidation state of the catalyst surface, which is important in the practical use of this material. The activity and selectivity of acrylic acid formation are discussed in relation with the relative levels of oxidation/reduction of the surface. (C) 2010 Elsevier B.V. All rights reserved.