Emission-line activity in type 2 quasars from the Sloan Digital Sky Survey

Villar-Martí,n, M.,Humphrey, A.,Martí,nez-Sansigre, A.,Pé,rez-Torres, M.,Binette, L.,Zhang, X. G. Blackwell Publishing Ltd 2008 Monthly notices of the Royal Astronomical Society Vol.390 No.1

<P>ABSTRACT</P><P>We have compared the optical emission-line ratios of type 2 quasars from Zakamska et al. with standard active galactic nucleus (AGN) photoionization model predictions, type 2 Seyfert galaxies, H <SMALL>II</SMALL> galaxies and narrow-line Fanaro–Riley type II radio galaxies. Moderate to high-ionization narrow-line radio galaxies and type 2 Seyfert galaxies are indistinguishable from type 2 quasars based on their optical line ratios. The standard AGN photoionization models, widely discussed for other type 2 AGN, can reproduce successfully the loci and trends of type 2 quasars in some of the main diagnostic diagrams. These models are not exempt of problems, and the discrepancies with the data are the same encountered for other type 2 AGN. As for these, realistic models must take into account a range of cloud properties, as widely demonstrated in the literature.</P><P>The Zakamska et al. sample is strongly biased towards objects with high line luminosities (L[O <SMALL>III</SMALL>] >10<SUP>42</SUP> erg s<SUP>−1</SUP>). We have found that stellar photoionization is obvious in a fraction of objects (3 out of 50) which are characterized by low [O <SMALL>III</SMALL>] luminosities compared with most type 2 quasars in the sample. We suggest that if the sample were expanded towards lower line luminosities (∼10<SUP>40–42</SUP> erg s<SUP>−1</SUP>) stellar photoionization might be evident much more frequently.</P><P>We explore an alternative scenario to pure AGN photoionization in which a varying contribution of stellar ionized gas contributes to the line fluxes. Although the models presented here are rather simplistic and not strong quantitative results can be extracted regarding the relative contribution of stellar versus AGN photoionization, our results suggest that adding a varying contribution of stellar photoionized gas works in the right direction to solve most of the problems affecting the standard AGN photoionization models. The ‘temperature problem’ on the other hand remains.</P>

Preparation of air stable nanoscale zero valent iron functionalized by ethylene glycol without inert condition

Ruiz-Torres, Claudio Adrian,Araujo-Martí,nez, René,Fernando,Martí,nez-Castañ,ó,n, Gabriel Alejandro,Morales-Sá,nchez, J. Elpidio,Guajardo-Pacheco, Jesú,s Mar& Elsevier 2018 Chemical Engineering Journal Vol.336 No.-

<P><B>Abstract</B></P> <P>The use of nanoscale zero-valent iron has been widely studied in recent years for potential application in environmental engineering, due to its affinity for a large number of contaminants, which may be in aqueous or solid phase, and for its abundance, which makes it an attractive tool for environmental remediation. However, there exist some variables in the production of nZVI that complicate the generation of the material, such as the complex methodologies of synthesis and the cost of inert conditions like nitrogen or argon atmosphere, which have the purpose of preventing the oxidation and reducing the instability of the material under ambient conditions. As a simple and economical synthesis methodology, this work presents an optimized method to synthesize functionalized nanoscale zero-valent iron (nZVI) using ethylene glycol (EG) without need for inert conditions. The coordination of iron ions during the nZVI-EG synthesis and the functionalization mechanism of the nanoparticles were identified by UV–Vis absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). Functionalized nZVI showed increased dispersibility due to the effects of steric repulsion between the grafted polymers. Ethylene glycol functionalized nZVI showed stability against oxidation during dry atmospheric condition, while significant oxidation was observed in the case of unfunctionalized nZVI. This result was also correlated with actual capacity for contaminant reduction. Therefore, the possibility was verified of using ethylene glycol in an effective surface modification method to prepare air stable nZVI for environmental remediation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Air-stable nZVI could be prepared by ethylene glycol without inert condition. </LI> <LI> Smaller and narrower size distribution could be obtained by functionalization. </LI> <LI> The nZVI-EG exhibited a protection effect against oxidation in oxic conditions. </LI> <LI> The reaction kinetics was not hindered by the organic functionalization agent EG. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Integral-field spectroscopy of type II QSOs at z= 0.3-0.4 : Integral-field spectroscopy of type II QSOs

Humphrey, A.,Villar-Martí,n, M.,Sá,nchez, S. F.,Martí,nez-Sansigre, A.,Delgado, R. Gonzá,lez,Pé,rez, E.,Tadhunter, C.,Pé,rez-Torres, M. A. Oxford University Press 2010 Monthly notices of the Royal Astronomical Society. Vol.408 No.1

Molecular Cosensitization for Efficient Panchromatic Dye-Sensitized Solar Cells

Cid, Juan-José,Yum, Jun-Ho,Jang, Song-Rim,Nazeeruddin, Mohammad K.,Martí,nez-Ferrero, Eugenia,Palomares, Emilio,Ko, Jaejung,Grä,tzel, Michael,Torres, Tomá,s WILEY-VCH Verlag 2007 Angewandte Chemie Vol.46 No.44

<B>Graphic Abstract</B> <P>Dyeing together: An efficient panchromatic dye-sensitized solar cell is constructed by using a “molecular cocktail” composed of an organic dye and a zinc phthalocyanine (see picture). The use of multiple, complementary dyes (cosensitization) is an important step towards solar cells that operate across the full spectrum of solar irradiation. <img src='wiley_img/14337851-2007-46-44-ANIE200703106-content.gif' alt='wiley_img/14337851-2007-46-44-ANIE200703106-content'> </P>

Combination of Mn oxidation states improves the photocatalytic degradation of phenol with ZnAl LDH materials without a source of O₂ in the reaction system

Morales-Mendoza, Getsemani,Alvarez-Lemus, Mayra,Ló,pez, Rosendo,Tzompantzi, Francisco,Adhikari, Rajesh,Lee, Soo Wohn,Torres-Martí,nez, Leticia M.,Gó,mez, Ricardo Elsevier 2016 CATALYSIS TODAY - Vol.266 No.-

<P><B>Abstract</B></P> <P>Mn-doped Zn/Al layered double hydroxides (LDH) materials were synthesized by the co-precipitation method. X-ray diffraction (XRD) analysis confirmed the polytype structure of LDH materials obtained as well as the successful incorporation of Mn into the structure. Atomic absorption spectroscopy (AAS) and energy dispersive X-ray spectroscopy (EDS) studies showed a well dispersion of Mn and a good correlation between the nominal and experimental composition. Scanning electron microscopy (SEM) revealed the formation of grains close to 1μm length. Energy band gap (Eg) of the solids determined by UV–vis diffuse reflectance spectroscopy (DRS) showed high photoresponse in the ultraviolet (UV) region, which was increased with Mn incorporation into the LDH structure. The LDH materials were evaluated in the photocatalytic degradation of phenol in aqueous medium, under UV radiation with and without O<SUB>2</SUB> source in the reaction system. The results showed that the O<SUB>2</SUB> is not an effective electron scavenger as usually occurs in TiO<SUB>2</SUB> photocatalyst. The Mn effect in the photocatalytic activity was notably marked in anaerobic condition however in aerobic or anaerobic conditions the presence of Mn increases the photoactivity. The phenol mineralization reached in anaerobic conditions was 95% (1.5ppm) of the initial concentration (30ppm) and it is maintained constant after 6h of radiation while in aerobic conditions the TOC reaches only 55% (13.5ppm). The role of Mn as charges separator is discussed and a suitable mechanism is proposed. This study shows that the Mn doped-Zn/Al LDH materials could be a promising photocatalysts under anaerobic conditions for the removal of phenol from aqueous medium.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ZnAl LDH rebuilt in phenol solution have not capacity to open the interlayer space. </LI> <LI> A source of O<SUB>2</SUB> have not influence in the phenol photooxidation with ZnAl LDH. </LI> <LI> Mn doped-ZnAl LDH increases the optical properties of absorption. </LI> <LI> The role as electron and hole trap of Mn takes advantage to separate charge. </LI> <LI> The Mn incorporation in ZnAl LDH materials improves the photocatalytic activity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Molecular Engineering of Zinc Phthalocyanines with Phosphinic Acid Anchoring Groups

Ló,pez‐,Duarte, Ismael,Wang, Mingkui,Humphry‐,Baker, Robin,Ince, Mine,Martí,nez‐,D&iacute,az, M. Victoria,Nazeeruddin, Mohammad K.,Torres, Tomá,s,Grä,tzel, Mich WILEY‐VCH Verlag 2012 Angewandte Chemie Vol.124 No.8

<P><B>Zwei Zinkphthalocyanin‐Photosensibilisatoren</B> mit verschiedenen Phosphinsäure‐Ankergruppen (siehe Schema) wurden synthetisiert. Solarzellen mit diesen Verbindungen verfügen über eine Photostromdichte von (7.6±0.2) mA cm<SUP>−2</SUP> bei geschlossenem Stromkreis, eine Spannung von (559±30) mV bei offenem Stromkreis und einen Füllfaktor von 0.76±0.03; dies entspricht einem Gesamtwirkungsgrad von 3.24 % unter 1 sun.</P>