Stabilizing Pd-cerium oxide-aluminum oxide catalysts for methane oxidation by reduction pretreatments

Pd-CeO2 based catalysts are state-of-the-art for methane oxidation, but deactivate due to Pd nanoparticle growth at high temperature. While encapsulation by CeO2 shells was reported to increase the stability of Pd nanoparticles (NPs), the established synthesis methods are not easily scalable. Here, we report the synthesis of PdO/CeOx/Al2O3 and CeOx/PdO/Al2O3 catalysts with improved stability for methane oxidation by sequential impregnation of Pd and Ce precursors on an Al2O3 support followed by reduction. The reduced catalysts displayed higher methane oxidation activity, and a lowering of the light-off temperature compared to the fresh calcined catalysts. High resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS) chemical imaging of the reduced catalysts indicated a redispersion of cerium oxide on the support surface and anchoring of Pd nanoparticles by cerium oxide. After aging at high temperature (850 °C), the activity of the reduced CeOx/PdO/Al2O3 catalysts remained high, while the activity of the calcined catalysts dropped significantly. The results showed that simple reduction pretreatments could improve the catalytic activity and stability of the catalysts at both low and high reaction temperatures through changing Pd-Ce interactions, restructuring of the surface and changes in the nature and types of adsorbed species, as shown by HRTEM, EDS and operando diffuse reflectance infrared Fourier transform spectroscopy. We believe that the proposed strategy can be used as a scalable alternative to embedding of Pd NPs by CeO2 in core-shell systems for enhanced thermal stability in exhaust after treatment applications

The influence of social disclosure on the relationship between Corporate Financial Performance and Corporate Social Performance*

Esta pesquisa tem como objetivo geral investigar o efeito moderador do disclosure do Corporate Social Performance (D-CSP) na relação entre Corporate Social Performance (CSP - Performance Social Corporativa) e Corporate Financial Performance (CFP - Performance Financeira Corporativa). Com base nesse objetivo, a pesquisa apresentou um modelo no qual o D-CSP atua como moderador em relação aos stakeholders primários (funcionários, comunidade e fornecedores). O D-CSP é um mecanismo pelo qual os diversos aspectos sociais envolvidos nas políticas, ações e atividades discricionárias identificados no gerenciamento para stakeholder podem ser avaliados. Para testar o modelo, utilizou-se uma amostra de 1.147 empresas pertencentes a 10 distintos setores e aos cinco continentes do planeta. Utilizaram-se dados da base Bloomberg de 2010 a 2014, totalizando 5.623 observações. A relação foi testada utilizando-se o modelo de regressão linear múltipla com dados em painel com efeitos fixos, recorrendo-se à correção de Newey-West erro padrão robusto. Para efetuar os testes, utilizaram-se três construtos: D-CSP, CSP e CFP. Empregou-se, como medida de CSP, a CSP dos stakeholders funcionários, fornecedores e comunidade. Como medida do D-CSP, aplicaram-se os scores de disclosure de CSP disponíveis na base de dados e, como medida da CFP, utilizou-se o retorno sobre ativo (ROA). Os testes realizados apontaram a existência do efeito moderador positivo do disclosure na relação entre CSP de stakeholders primários e CFP. Os resultados permitem inferir que, além de apresentar um CSP positivo em relação aos stakeholders primários, é necessário divulgar tais resultados, contribuindo para desempenhos financeiros superiores.This study’s general objective is to investigate the moderating effect of Corporate Social Performance Disclosure (D-CSP) on the relationship between Corporate Social Performance (CSP) and Corporate Financial Performance (CFP). Based on this objective, the study presented a model in which D-CSP acts as a moderator in relation to primary stakeholders (employees, community, and suppliers). D-CSP is a mechanism through which the various social aspects involved in discretionary policies, actions, and activities identified in the management for stakeholders process can be evaluated. A sample of 1,147 companies belonging to 10 different sectors and five continents was used to test the model. Data were collected from the Bloomberg database, totaling 5,735 observations, from 2010 to 2014. The relationship was tested using the multiple linear regression model involving panel data with fixed effects, and the Newey-West robust standard errors correction. Three constructs, D-CSP, CSP, and CFP, were used to perform the tests. As a CSP measure, the CSP of the employee, supplier, and community stakeholders was used. As a D-CSP measure, the CSP disclosure scores available from the database were used, and return on assets (ROA) was used as a CFP measure. The tests carried out indicated the existence of a positive moderating effect of disclosure on the relationship between the CSP of primary stakeholders and CFP. Besides presenting a positive CSP in relation to the primary stakeholders the results enable it to be inferred that these results need to be disclosed, thus contributing to higher corporate financial performance

The Eldivan ophiolite and volcanic rocks in the İzmir–Ankara–Erzincan suture zone, Northern Turkey: Geochronology, whole-rock geochemical and Nd–Sr–Pb isotope characteristics

Gabbros and dolerite dikes of the Eldivan ophiolite and basaltic volcanic rocks of the ophiolitic mélange in the central part of the İzmir–Ankara–Erzincan (IAE) suture zone were investigated for their 40Ar/39Ar age and whole-rock-major-trace element and Sr–Nd–Pb isotope compositions. Based on geological and geochemical characteristics basaltic volcanic rocks in the ophiolitic mélange are subdivided into two groups (Groups I and II) with ocean island basalts or enriched mid-ocean ridge basalt characteristics, respectively. Gabbros and dolerite dikes of the Eldivan ophiolite (Groups III and IV) have instead geochemical compositions indicative of a subduction-related environment. The volcanic rocks of Group I have 87Sr/86Sr(i) between 0.7037 and 0.7044, ƐNd(i)–DM of −4.5 to −5.6, and 206Pb/204Pb(i) ranging between 18.35 and 18.75. Group II volcanic rocks have higher 87Sr/86Sr(i) values (0.7049–0.7055), ƐNd(i)–DM ranging between −5.4 and −6.0, and 206Pb/204Pb(i) between 18.14 and 18.62. The Nd isotopic signatures and 207Pb/204Pb(i) values of the volcanic rocks of both groups point to a different source with respect to those of the Eldivan ophiolite. The low 206Pb/204Pb(i) values relative to the ophiolitic rocks seem to exclude a significant contribution from a HIMU reservoir, whereas the 207Pb/204Pb(i) values slightly above the NHRL might indicate some contribution from an EM2-type reservoir. Gabbros (Group III) of the Eldivan ophiolite and dolerite dikes (Group IV) cross-cutting the ultramafic part of the ophiolite show 87Sr/86Sr(i) between 0.7038 and 0.7053, ƐNd(i)–DM from −2 to −3.6 and 206Pb/204Pb(i) between 18.10 and 18.80. The gabbros yield ca. 150 Ma 40Ar/39Ar amphibole-plateau ages, which, together with the geochemical data, indicate that they were produced above subducted oceanic lithosphere in the IAE ocean domain in Late Jurassic times. Therefore, the Eldivan ophiolite in the IAE suture zone constitutes a link between the Hellenide–Dinaride ophiolite belts to the west and the Armenian–Iranian ophiolites to the east

Geochemical characteristics and age of metamorphic sole rocks within a Neotethyan ophiolitic mélange from Konya region (central southern Turkey)

Palaeo- and Neo-Tethyan-related magmatic and metamorphic units crop out in Konya region in the south central Anatolia. The Neotethyan assemblage is characterized by mélange and ophiolitic units of Late Cretaceous age. They tectonically overlie the Middle Triassic-Upper Cretaceous neritic to pelagic carbonates of the Tauride platform. The metamorphic sole rocks within the Konya mélange crop out as thin slices beneath the sheared serpentinites and harzburgites. The rock types in the metamorphic sole are amphibolite, epidote-amphibolite, garnet-amphibole schist, plagioclase-amphibole schist, plagioclase-epidote-amphibole schist and quartz-amphibole schist. The geochemistry of the metamorphic sole rocks suggests that they were derived from the alkaline (seamount) and tholeiitic (E-MORB, IAT and boninitic type) magmatic rocks from the upper part of the Neotethyan oceanic crust. Four samples from the amphibolitic rocks yielded 40Ar/39Ar isotopic ages, ranging from 87.04 ±.36 Ma to 84.66 ±.30 Ma. Comparison of geochemistry and geochronology for the amphibolitic rocks suggests that the alkaline amphibolite (seamount-type) cooled below 510 ± 25 °C at 87 Ma whereas the tholeiitic amphibolites at 85 Ma during intraoceanic thrusting/subduction. When all the evidence combined together, the intraoceanic subduction initiated in the vicinity of an off-axis plume or a plume-centered spreading ridge in the Inner Tauride Ocean at 87 Ma. During the later stage of the steady-state subduction, the E-MORB volcanics on the top of the down-going slab and the arc-type basalts (IAT/boninitic) detached from the leading edge of the overriding plate, entered the subduction zone after ~2 my and metamorphosed to amphibolite facies in the Inner Tauride Ocean. Duration of the intraoceanic detachment (~87 Ma) and ophiolite emplacement onto the Tauride-Anatolide Platform (Tavşanli Zone), followed by subsequent HP/LT metamorphism (~82 Ma) spanned ~5 my in the western part of the Inner Tauride Ocean. © 2014 © 2014 Taylor & Francis

Stratigraphy and Ar/Ar geochronology of the Miocene lignite-bearing Tuncbilek-Domanic Basin, western Anatolia

The Tuncbilek-Domani Basin is one of the Neogene basins containing economic coal deposits in western Anatolia, Turkey. The basin fill represents fluvial to lacustrine sedimentary units which are interlayered with volcanic rocks with bimodal composition. In order to reveal the stratigraphy and the exact ages of the basin fill and coal deposits, and to explore the tectonic evolution of the basin, we present new field data and Ar/Ar age data from the volcanic units. The field studies and the age data indicate that the whole basin fills were deposited between similar to 23 and similar to 19 Ma (Aquitanian-Early Burdigalian) without any unconformity. Taking into account the ages of the coal-bearing sedimentary units in the other Neogene basins in the region, it is concluded that most of the economic coal deposits in the western Anatolia were formed during Aquitanian. The field studies also show that the deposition of the sedimentary units in the basin was controlled by the NE-SW-trending strike- to oblique-slip normal faults. In a regional scale, tectonic evolution of the Tuncbilek-Domanic Basin is linked to the differential stretching in the hanging wall of the southerly located, a crustal-scale low-angle detachment fault (the Simav detachment fault) that controlled the Early Miocene exhumation of the Menderes Extensional Core Complex

Tectono-stratigraphy of the Neogene basins in Western Turkey: Implications for tectonic evolution of the Aegean Extended Region

The western part of the Aegean region includes several Neogene basins containing volcano-sedimentary successions. The Neogene basins, located along the northern Menderes Extensional Metamorphic Complex (MEMC) were developed during the Miocene as supra-detachment basins. They contain two distinct volcano-sedimentary successions, separated by a regional unconformity. The basins located to the west of the MEMC were developed as strike-slip basins and contain volcanic and sedimentary units getting younger from NE to SW with no remarkable unconformity

Low-sulfidation type Au-Ag mineralization at Bergama, Izmir, Turkey

Bergama, the center of Bergama County, is located in western Turkey and includes the villages of Ovacik, Narlica and Saganci. The Ovacik epithermal gold-silver deposit is located in the Western Anatolian Volcanic and Extensional Province, adjacent to the ENE-trending Bergama graben, some 100 km north of the city of Izmir. Gold of economic grades at the Ovacik deposit (reserves 4.19 Mt at 7.6 g/t) occurs in epithermal quartz veins which display low-temperature epithermal textures, including crustiform banding, quartz pseudomorphs after bladed calcite, and multiphase hydrothermal breccias. Alteration minerals at both Ovacik and Narlica are dominated by smectite, mixed-layer illite/smectite, chalcedonic quartz and adularia, whereas major kaolinite and minor mixed-layer smectite/illite (> 13.4 Å) occur at Saganci. The total sulfide content at Ovacik is low (< 2%) and is dominated by pyrite with traces of electrum, chalcopyrite, arsenopyrite, acanthite, tetrahedrite, pyrargyrite, stibnite, galena, chalcocite, bornite, covellite and sphalerite, occurring mainly within breccia clasts. Pyrite and marcasite appear to be the most common opaque minerals at Narlica and form dark sulfide-rich bands along with traces of electrum, native silver and chalcopyrite; pyrite is the only sulfide identified at Saganci. 40Ar/39Ar dating of adularia from gold-bearing quartz veins indicates an age of mineralization of about 18.2 ± 0.2 Ma. Fluid inclusion studies at Ovacik reveal that main-stage quartz contains predominantly liquid-rich inclusions with homogenization temperatures (Th) ranging from 150 to 305 °C, with the majority of Th varying between 165 to 205 °C: ice-melting temperatures (Tm) ranging from - 0.4 to - 1.2 °C (salinity < 2 wt.% NaCl equiv.) are dominant. Higher Th (220 to 248 °C) at the Narlica deposit may be attributed to the deeper level of exposure. Geochemical variations in altered wall rocks at Ovacik and Narlica are generally characterized by two-fold enrichments in K, Rb, Cs and 25 to 93% depletions in Sr, Ca, Mg, Na and even higher depletions (96 to 99% decrease) in the quartz-adularia vein zone. Lanthanum, Ce, Pr, Hf, Zr, Sm, Eu, Gd, Tb and Ho also exhibit up to 50% depletions in the wall rock and even more so (up to 90% depletion for La and Nd) in the vein structure. Wall rock enrichment in Au, Ag, As, Hg and Sc is by factors of 60, 150, 88, 8 and 3, respectively. The ranges of REE in both the altered volcanic rocks and quartz-adularia veins are wide and may reflect either significant mobilization of REE during alteration and mineralization or their dilution by the metasomatic processes from fresh volcanic rocks through montmorillonite-illite-adularia-altered wallrock to quartz-adularia veins. High Rb/Sr ratios in adularia-illite-altered areas are closely related to the presence of K-rich alteration minerals. Low Rb/Sr ratios and corresponding low K values at Saganci are due to acid leaching of volcanic rocks. Positive correlation coefficients between Au and Ag, Pb, Zn, Cd, Cu and Sb in epithermal quartz veins, all of which are > 0.51, are significant. Silver and Sb are remarkably enriched at higher levels of the deposit. No correlation occurs between Au and As or Ag and As. The Ovacik quartz in Au-Ag-bearing veins has ?18O values ranging from + 9.5 to + 15.7‰, whereas ?D values of fluid inclusions in quartz range from - 89 to - 125‰. However, the Narlica quartz in Au-Ag bearing veins returned ?18O values ranging from + 5.9‰ to + 8.3, whereas the ?D values of fluid inclusion in quartz range from - 82 to - 99‰. ?18O results indicate that ore-forming hydrothermal fluids at Ovacik and Narlica had ?18OH2O values ranging from - 2.9 to + 3.5‰ (average: - 0.24‰) and from - 2.96 to - 0.6 (average - 1.6), respectively. They are thus 18O-enriched in comparison with present-day meteoric and hydrothermal meteoric waters (- 5.4‰). ?18O, ?18OH2O and ?D values suggest that mineralizing solutions were a mixture of meteoric and magmatic waters. The ?34S?sulfide data at Ovacik and Narlica range from - 2.1 to 5.3‰ (average: + 1.7) and from - 4.6 to + 2.7‰ (average: - 0.36), respectively. These ?34S?sulfide values are consistent with a magmatic source for S. © 2006 Elsevier B.V. All rights reserved.National Council for Scientific Research 103Y003This study was financially supported by the National Research Council of Turkey (TUBITAK) under grant No: 103Y003. The authors are grateful to the staff of Normandy Gold Mine, Ovacik/Bergama for their help during core sampling and field work. We thank Ferenc Molnár and Peter Kodera for their detailed and thorough comments. Language review by Kerim Sener is greatly appreciated. Appendix A A.

Comparative study of the characteristics and activities of Pd/γ-Al \u3csub\u3e2\u3c/sub\u3e O \u3csub\u3e3\u3c/sub\u3e catalysts prepared by vortex and incipient wetness methods

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. 5 wt% Pd/γ-Al 2 O 3 catalysts were prepared by a modified Vortex Method (5-Pd-VM) and Incipient Wetness Method (5-Pd-IWM), and characterized by various techniques (Inductively coupled plasma atomic emission spectroscopy (ICP-AES), N 2 -physisorption, pulse CO chemisorption, temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), and X-ray diffraction (XRD)) under identical conditions. Both catalysts had similar particle sizes and dispersions; the 5-Pd-VM catalyst had 0.5 wt% more Pd loading (4.6 wt%). The surfaces of both catalysts contained PdO and PdO x with about 7% more PdO x in 5-Pd-VM. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and scanning electron microscope (SEM) images indicated presence of PdO/PdO x nanocrystals (8-10 nm) on the surface of the support. Size distribution by STEM showed presence of smaller nanoparticles (2-5 nm) in 5-Pd-VM. This catalyst was more active in the lower temperature range of 275-325 °C and converted 90% methane at 325 °C. The 5-Pd-VM catalyst was also very stable after 72-hour stability test at 350 °C showing 100% methane conversion, and was relatively resistant to steam deactivation. Hydrogen TPR of 5-Pd-VM gave a reduction peak at 325 °C indicating weaker interactions of the oxidized Pd species with the support. It is hypothesized that smaller particle sizes, uniform particle distribution, and weaker PdO/PdO x interactions with the support may contribute to the higher activity in 5-Pd-VM

U-Pb and 40Ar-39Ar geochronology of the ophiolites and granitoids from the Tauride belt: Implications for the evolution of the Inner Tauride suture

The Inner Tauride ocean separated the Tauride-Anatolide Block from the Central Anatolian Crystalline Complex. This oceanic basin was consumed as a result of north-dipping subduction and closed during the latest Cretaceous to early Cenozoic times. Subduction-related magmatism and metamorphism occurred at different stages during the closure of the Inner Tauride ocean. The ophiolites and granitoids record the tectonic events. In this paper, we present new U-Pb zircon age determinations by LA-MC-ICP-MS and 40Ar-39Ar age dating of selected ophiolites (Mersin, Pozanti-Karsanti, Pinarbaşi and Divrigi) and granitoids (Horozköy and Divrigi) along the Inner Tauride suture zone. The results show that: (i) the crystallization age of SSZ oceanic crust is ~89Ma and the magmatic activity continued until just prior to ophiolite emplacement onto the Tauride-Anatolide platform during the latest Cretaceous (Maastrichtian), (ii) the timing of intraoceanic thrusting/subduction is constrained as ~89Ma, which is consistent with steady-state subduction in a forearc tectonic setting, (iii) the timing of collision of the Tauride-Anatolide passive margin with the subduction trench of the Inner Tauride ocean and subsequent slab break-off occurred from 76 to 67Ma, and (iv) the timing of continent-continent collision between the Central Anatolian Crystalline Complex and the Tauride-Anatolide Block is constrained as Eocene (50-49Ma). The first three tectonic stages overlap each other during the closure of the Inner Tauride oceanic basin. 'Soft' collision of the subduction trench with the passive margin was followed by hard-collision and suture tightening ~8-10My later. © 2012 Elsevier Ltd.MMF2011BAP16 106Y231This work is supported by TÜBİTAK (Project no: 106Y231 ) and partly by Çukurova University Research Foundation (project no: MMF2011BAP16 ). Fatih Karaoğlan acklowledges International Research Fellowship Programme support from TÜBİTAK–BİDEB . Alastair Robertson, Yener Eyüboğlu and Erdin Bozkurt are thanked for their valuable comments and suggestions that improved the manuscript. Appendix

The origin of carbonatites from the eastern armutlu peninsula (Nw turkey)

Unusual carbonate dykes, which have a thickness of up to 4 m, cross-cut the amphibolites from the high-grade metamorphic rocks in the Armutlu Peninsula (NW Turkey). They are described as carbonatites on the basis of their petrographic, geochemical and isotope-geochemical characteristics. The carbonatites, which commonly show equigranular texture, are composed of calcite and clinopyroxene with other minor phases of plagioclase, mica, garnet, K-feldspar, quartz, epidote, titanite and opaque minerals. They contain abundant xenoliths of pyroxenite and amphibolite. The geochemical characteristics of the carbonatites are significantly different from those of mantle-derived carbonatites. They have remarkably low incompatible element (e.g. Ba, Th, Nb) and total REE (11–91 ppm) contents compared with mantle-derived carbonatites. The high87Sr/86Sr(i) (0.70797–0.70924) and low εNd(t) (−8.08 to −9.57) of the carbonatites confirm that they were derived from the continental crust rather than from a mantle source. Mica from carbonatite was dated by the40Ar/39 Ar method, yielding a Late Jurassic–Early Cretaceous age (148–137 Ma). This is significantly younger than the age of adjacent amphibolites (Upper Triassic). All data from field studies, as well as petrographic, geochemical and geochronological observations, suggest that these carbonatites were formed from anatectic melting of a carbonated source area in the continental crust