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Porous carbons have become extremely important in many applications related to environmental remediation and, more recently, to challenging energy issues. Then, great efforts have been addressed to the design and production of carbon materials for emergent energy applications. Various templating approaches have emerged as suitable alternatives to traditional methods based on physical or chemical activation procedures. This review focuses on simple, sustainable templating strategies based on the use of easily removable inorganic particles (e.g., NaCl, MgO, CaCO3, ZnO) or polymeric materials (i.e., HIPE emulsions, block copolymers, surfactants). The fundamental aspects, advances, applications, and challenges are analyzed in detail. This review provides useful information for researchers interested in easy methodologies for producing porous carbons with a variety of morphologies and pore structures intended for a wide range of applications, including energy storage and production., This research work was supported by projects RTI2018-093712-B-I00 (MCIU/AEI/FEDER, UE) and IDI/2018/000148 (regional GRUPIN2018).

Purpose: The exposure to violence increases risk for future involvement; however, given that the transmission of violence is not universal, mechanisms underlying such association must be explored. The main aim of this study was to analyze the contribution of expected costs and benefits of aggressive behavior and romantic attachment to the association between past and present teen dating violence. Methods: A stratified two-stage cluster sampling was used to select a sample of 593 high school students. Participants were between 15 and 18 years old (M=16.97, SD=0.95; 41.82% male and 58.18% female) and were either currently involved or had been involved in at least one serious relationship in the previous 12 months. Results: An association between past and current aggressive behavior in dating relationships was found, as well as between dating violence and expected benefits of aggression. Other analyzed variables were found to have little or no influence on current dating violence perpetration (i.e., verbal-emotional, physical and sexual). Conclusions: This study offers evidence of the importance of early intervention. In addition, it is essential to change adolescent perceptions regarding any expected benefits of aggression and to promote skills as an alternative to violence. This study was fund by the Spanish Ministry of Economy and Competitiveness: National Subprogram for Knowledge Generation 2013 - Excellence (ref. PSI2013-46830-P). This sponsor had no involvement in the study design, the collection, analysis, and interpretation of data, the writing of the report, the decision to submit the paper for publication, etc.

Iron/Nitrogen-doped carbon catalysts are considered to be one of the most promising candidates to replace platinum-based catalysts for the oxygen reduction reaction in the cathode of the fuel cell. Herein, we demonstrate a simple and cost-effective strategy for the fabrication of Fe-N-C-mesoporous-carbons involving the carbonization of calcium citrate followed by a post-treatment with urea and ammonium sulfate iron (II). The synthesized materials exhibit high values of surface area, large nitrogen and iron contents. The iron is present in two configurations: i) γ-iron phase and ii) iron coordinated to nitrogen (Fe-Nx). When used as an electrocatalyst in basic electrolyte, the Fe-N-C material predominantly catalyzes the four-electron pathway with an onset potential of 0.91 V and a half-wave potential of 0.81 V. In acidic electrolyte, the optimized catalyst exhibits an onset potential of 0.73 V. The experimental results show that the N-functionalities and the Fe-N coordination sites play a major role in catalytic performance in both kinds of electrolytes and that the ɣ-iron phase has little or no catalytic effect. In this regard, pure N-doped carbon shows to be better catalyst than pure Fe-doped carbon. Hence, these results provide useful guidelines for the development of highly active and cost-effective ORR catalysts., This research work was supported by the FICYT Regional Project (GRUPIN14-102), and the Spanish MINECO-FEDER (CTQ2015-63552-R).

A simple one-pot route for the synthesis of highly porous N-doped carbons with an excellent performance as supercapacitor electrodes is presented. The synthesis scheme is based on the carbonization of an organic salt, potassium citrate, at a temperature in the 700-900 ºC range, in the presence of urea. Such porous carbons combine ultra-high BET surface areas of up to 3350 m2·g-1, a large pore volume of up to 2.65 cm3·g-1, a porosity which can be regulated to have a micropore or micro-mesopore network and a notable nitrogen content in the 0.5-4.5 wt % range, two essential properties for their use in electrochemical devices. The presence of urea in the synthesis mixture is the key to pore development in these synthesized carbons. The applicability of this type of carbon as supercapacitor electrode material with an ionic liquid as electrolyte has also been demonstrated in this study., This research work was supported by the FICYT Regional Project (GRUPIN14-102), and the Spanish MINECO-FEDER (CTQ2015-63552-R).

A novel activating agent for the production of highly microporous carbons with textural properties that match those of superactivated carbons prepared by KOH activation, i.e. BET surface areas of 2600–3000 m2 g−1, pore volumes of ∼1.3–1.6 cm3 g−1 and pore size distributions in the supermicropore-small mesopore (, This research work was supported by the FICYT Regional Project (GRUPIN14-102) and Spanish MINECO/FEDER (CTQ2015-63552-R). G. A. F. thanks the MINECO for his predoctoral contract.

A simple, cost-effective and scalable approach for the synthesis of N-doped mesoporous carbons that are effective as ORR catalysts is reported. The synthesis procedure involves two steps: a) production of mesoporous carbons using a template-free approach based on the carbonization of citrate salts of zinc and calcium, and b) N-doping by heat treatment in the presence of melamine. The resulting N-doped carbon possess a high specific surface area, a porosity made up exclusively of mesopores and a large amount of nitrogen functionalities (∼8–9 wt%). When used as an electrocatalyst for the oxygen reduction reaction (ORR), the metal-free carbon materials predominantly catalyze the 4 e− process, with an onset potential of 0.9 V (vs. RHE) and a superior kinetic current density (∼17 mA cm−2) to that of Pt/C at ∼0.6 V under basic conditions. In addition, the developed catalysts show a higher stability than commercial Pt/C and excellent electrocatalytic selectivity against methanol crossover., This research work was supported by the Spanish Ministerio de Economía y Competitividad, MINECO (MAT2012-31651), Fondo Europeo de Desarrollo Regional (FEDER) and FICYT Regional Project (GRUPIN14-102). G. A. F. thanks the MINECO for his predoctoral contract and M. S. thanks the Spanish Ministerio de Ciencia e Innovación for her Ramón y Cajal contract.

Flexible supercapacitors have aroused a great deal of interest for their integration in portable, flexible and wearable electronic devices. In this context, graphene has emerged as an excellent building block for the fabrication of flexible electrodes. However, free-standing graphene films suffer from a certain lack of mechanical resistance, which limits their use. In this paper, we report on the fabrication of free-standing and flexible composites with enhanced robustness, consisting of a graphene layer deposited over a porous cellulose tissue. The coated graphene consists of two types of holey graphene units (i.e. wrinkled graphene sheets and graphene nanoscrolls) that produce closely interconnected and porous 3D graphene architectures. The graphene-tissue composites developed here have a thickness of around 60 µm and areal densities in the 0.6–2.4 mg cm−2 range. These composites have a very open structure that provides easy access to the electrolyte, thereby guaranteeing high ion-transport rates. In consequence, they show a remarkable capacitive performance in both liquid (1 M H2SO4) and solid (PVA-H2SO4) electrolytes. The supercapacitors assembled with these materials possess an areal capacitance of up to ~80 mF cm−2 at low rates in both kinds of electrolyte and around 60 mF cm−2 at 500 mA cm−2 in H2SO4 and 54 mF cm−2 at ca. 80 mA cm−2 in a gel electrolyte. What is more, these SCs are able to deliver ca. 9 µWh cm−2 of energy at a high power density of 100 mW cm−2., This research work was supported by the FICYT Regional Project (GRUPIN14- 102) and Spanish MINECO (CTQ2015-63552-R).

N-doped highly dense uniform carbon microspheres of around 1 μm have been prepared by a nanocasting strategy using silica particles as template and a nitrogen-rich substance (i.e. pyrrole) as carbon precursor. These carbon microspheres possess a large number of nitrogen functional groups (∼ 9 wt % N), a high BET surface area of up to ∼ 1300 m2 g−1 with a porosity made up mostly of micropores (< 2 nm), and a high packing density of 0.97 g cm−3. They also show a remarkable volumetric capacitance of ca. 290 F cm−3 in H2SO4 as a result of pseudocapacitance effects arising from the N-groups, such that they are able to keep 50 % of the capacitance at a high current density of 40 A g−1. An additional chemical activation process with KOH has been performed to enhance the microporous network. These highly porous microspheres (2690 m2 g−1), that have a lower nitrogen content (∼ 2 % wt), can achieve 92 F cm−3 in TEABF4/AN while displaying 83 % of capacitance retention at a high current density of 40 A g−1., This research work was supported by Spanish Ministerio de Economía y Competitividad, MINECO (MAT2012-31651), and Fondo Europeo de Desarrollo Regional (FEDER). G. A. F. thanks the MINECO for his predoctoral contract and M. S. thanks the Spanish Ministerio de Ciencia e Innovación for her Ramón y Cajal contract.

N-doped highly microporous carbons have been successfully fabricated from N-rich microalgae by the combination of low-cost hydrothermal carbonization and industry-adopted KOH activation processes. The hydrothermal carbonization process was found to be an essential step for the successful conversion of microalgae into a carbon material. The materials thus synthesized showed BET surface areas in the range ∼1800–2200 m2 g−1 exclusively ascribed to micropores. The carbons showed N contents in the 0.7–2.7 wt.%, owing to the use of N-rich microalgae as a carbon precursor. When tested in symmetric double layer capacitors (occasionally called supercapacitors) based on aqueous LiCl electrolytes, pseudocapacitance was only observable for the sample synthesized at the lowest temperature, 650 °C, which is the one exhibiting the largest amount of N- and O-containing groups. The samples synthesized at 700–750 °C exhibited excellent rate capability (only 20% of capacitance loose at 20 A g−1), with specific capacitances of 170–200 F g−1 at 0.1 A g−1. These materials showed excellent long-term cycling stability under high current densities., The financial support for this research work provided by the US Army Research Office (grant W911NF-12-1-0259) and by the Spanish MINECO (MAT2012-31651) is gratefully acknowledged. M.S. thanks the Spanish MINECO for the award of a Ramón y Cajal contract.

[EN] Macro/mesoporous carbon monoliths with a graphitic framework were synthesized by carbonizing polymeric monoliths of poly(benzoxazine-co-resol). The overall synthesis process consists of the following steps: (a) the preparation of polymeric monoliths by co-polymerization of resorcinol and formaldehyde with a polyamine (tetraethylenepentamine), (b) doping the polymer with a metallic salt of Fe, Ni or Co, (c) carbonization and (d) the removal of inorganic nanoparticles. The metal nanoparticles (Fe, Ni or Co) formed during the carbonization step catalyse the conversion of a fraction of amorphous carbon into graphitic domains. The resulting carbon monoliths contain >50 wt.% of graphitic carbon, which considerably improves their electrical conductivity. The use of tetraethylenepentamine in the synthesis results in a nitrogen-containing framework. Textural characterization of these materials shows that they have a dual porosity made up of macropores and mesopores (∼2–10 nm), with a BET surface area in the 280–400 m2 g−1 range. We tested these materials as electrodes in organic electrolyte supercapacitors and found that no conductive additive is needed due to their high electrical conductivity. In addition, they show a specific capacitance of up to 35 F g−1, excellent rate and cycling performance, delivering up to 10 kW kg−1 at high current densities., The financial support for this research work provided by the Spanish MCyT (CQT2011-24776 and MAT2012-31651) is gratefully acknowledged. M. S. thanks the Spanish MCyT for the award of a Ramón y Cajal contract.

[EN] The synthesis of highly functionalized porous silica–carbon composites made up of sulfonic groups attached to a carbon layer coating the pores of three types of mesostructured silica (i.e. SBA-15, KIT-6 and mesocellular silica) is presented. The synthesis procedure involves the following steps: (a) removal of the surfactant, (b) impregnation of the silica pores with a carbon precursor, (c) carbonization and (d) sulfonation. The resulting silica–carbon composites contain ∼30 wt % of carbonaceous matter with a high density of acidic groups attached to the deposited carbon (i.e.single bondSO3H, single bondCOOH and single bondOH). The structural characteristics of the parent silica are retained in the composite materials, which exhibit a high surface area, a large pore volume and a well-ordered porosity made up uniform mesopores. The high density of the sulfonic groups in combination with the mesoporous structure of the composites ensures that a large number of active sites are easily accessible to reactants. These sulfonated silica–carbon composites behave as eco-friendly, active, selective, water tolerant and recyclable solid acids. In this study we demonstrate the usefulness of these composites as solid acid catalysts for the esterification of maleic anhydride, succinic acid and oleic acid with ethanol. These composites exhibit a superior intrinsic catalytic activity to other commercial solid acids such as Amberlyst-15., This work was supported by Spanish MICINN (Project CQT2011-24776). M.S. and P.V-V. acknowledge the Ramon y Cajal and JAE-Predoc contracts respectively.

[EN] Highly porous carbons have been prepared by the chemical activation of two mesoporous carbons obtained by using hexagonal- (SBA-15) and cubic (KIT-6)-ordered mesostructured silica as hard templates. These materials were investigated as sorbents for CO2 capture. The activation process was carried out with KOH at different temperatures in the 600–800 °C range. Textural characterization of these activated carbons shows that they have a dual porosity made up of mesopores derived from the templated carbons and micropores generated during the chemical activation step. As a result of the activation process, there is an increase in the surface area and pore volume from 1020 m2 g−1 and 0.91 cm3 g−1 for the CMK-8 carbon to a maximum of 2660 m2 g−1 and 1.38 cm3 g−1 for a sample activated at 800 °C (KOH/CMK-8 mass ratio of 4). Irrespective of the type of templated carbon used as precursor or the operational conditions used for the synthesis, the activated samples exhibit similar CO2 uptake capacities, of around 3.2 mmol CO2 g−1 at 25 °C. The CO2 capture capacity seems to depend on the presence of narrow micropores (, The financial support for this research work provided by the Spanish MCyT (MAT2008-00407) is gratefully acknowledged. P. V-V. and M. S. thank the Spanish MCyT for the award of a grant (JAE-Predoc) and a Postdoctoral Mobility contract, respectively.

[EN] Highly porous carbons have been successfully synthesized by chemical activation of polythiophene with KOH. The activation process was performed under relatively mild activation conditions, i. e., a KOH/polymer weight ratio of 2 and reaction temperatures in the 600–850 °C range. The porous carbons thus obtained possess very large surface areas, up to 3000 m2/g, and pore volumes of up to 1.75 cm3/g. The pore size distribution of these carbons can be tuned via modification of the activation temperature. Thus, by increasing the activation temperature from 600 to 850 °C, the nature of the carbons changes gradually from microporous to micro-mesoporous (with small mesopores of up to 2.5 nm). The polythiophene-derived activated carbons are sulfur-doped with sulfur contents in the 3–12 wt% range. The sulfur content decreases at higher activation temperature. The hydrogen storage capacity of these activated carbons, at cryogenic temperature and 20 bar, is up to 5.71 wt% with an estimated maximum hydrogen uptake of 6.64 wt%. Their ease of preparation and high uptake makes the polythiophene-derived carbons attractive hydrogen storage materials., The financial support provided by the Spanish MCyT (MAT2008-00407) is gratefully acknowledged. M. S. thanks the Spanish MCyT for the award of a Postdoctoral Mobility contract

7 pages, 6 figures, 1 table.-- Available online Aug 28, 2008., Graphitic carbon nanocoils with a high degree of crystallinity have been synthesized by using as intermediates hydrothermally carbonized samples (here denoted as hydrochar) obtained from three representative saccharides (glucose, sucrose and starch). The hydrochar samples were converted to graphitic nanocoils at moderate temperatures (900°C) using nickel nanoparticles as a graphitization catalyst. The synthesis method involves two simple steps: (a) pyrolysis of the Ni impregnated samples at 900°C and (b) liquid-phase oxidation to remove the metallic particles and the non-graphitized (amorphous) carbon. This synthesis scheme allows the fabrication of uniform nanostructures of graphitic nanocoils, with a high level of crystallinity as was demonstrated by different techniques (HRTEM, SAED, XRD and Raman spectroscopy)., The financial support for this research work provided by the Spanish MCyT (MAT2005-00262) is gratefully acknowledged. M.S. acknowledges the assistance of the Spanish MCyT for the award of a FPU grant.

3 pages, 3 figures, 1 table. -- Printed version published 1 Dec 2008. -- Issue title: Non-Crystalline Solids 9, 9th International Workshop on Non-Crystalline Solids (Porto, Portugal, 27-30 April 2008), Combining different experimental techniques, the physical properties of Fe nanoparticles (NPs) randomly dispersed in a porous carbon have been investigated. From the analysis of TEM images and the broad maximum observed in ZFC–FC magnetization measurements under an applied magnetic field of 2.5 mT, a broad-size distribution NPs (5–50 nm) is estimated. The nature of these NPs (α-Fe and γ-Fe) was determined from X-ray diffraction. Furthermore, magnetization measurements suggest that these Fe-NPs remain completely blocked below 60 K due to a magnetic exchange-bias coupling induced on the surface of these NPs. However, the true nature of the core–shell responsible for this exchange bias within the NPs, is not totally understood yet. In addition, the system begins to be magnetically unblocked above 60 K, becoming almost superparamagnetic above 200 K. Room temperature Mössbauer spectroscopy confirms the existence of both α- and γ-Fe phases; an additional quadrupole component is required to properly fit the spectrum, which could be associated with the NP’s shell or to an oxide phase probably located on the surface of the NPs., The work was supported by the Spanish MCyT (MAT2005-06806-C04-01 and MAT2005-00262). One of the authors, M.P.F.-G., acknowledges the Spanish MEC for the award of a FPI Grant during the collaboration with the University of Porto. Authors are also endebted to: D. Martínez-Blanco for magnetic measurements; Dr C. Alvarez-Rua for X-ray diffraction, C. Alvarez and A. Quintana for Electronic Microscopy, all of them from SCT’s at University of Oviedo, as well as University of Porto and IFIMUP for the assistance and experimental equipment provided.

5 pages, 4 figures, 1 table.-- Available online Nov 5, 2008., Highly graphitic carbon nanocoils (GCNC) were synthesized through the catalytic graphitization of carbon microspheres obtained by the hydrothermal carbonization of different saccharides (sucrose, glucose and starch) and were used as a support for Pt nanoparticles. The Pt nanoparticles were deposited by means of a polymer mediated-polyol method. The Pt catalysts were characterized both physically (XRD, TEM, HRTEM and XPS) and electrochemically (electrooxidation of methanol in an acid medium). The electrocatalysts thus prepared show a high dispersion of Pt nanoparticles, with diameters in the 3.0–3.3 nm range and a very narrow particle size distribution. These catalytic systems possess high electroactive Pt surface areas (up to 85 m2 g−1 Pt) and they exhibit large catalytic activities towards methanol electrooxidation (up to 201 A g−1 Pt). Moreover, they have a high resistance against oxidation, which is considerably greater than that of the Pt/Vulcan system., The financial support for this research work provided by the Spanish MCyT (MAT2008-00407, MAT2007-60621 and FEDER) is gratefully acknowledged. M.S. and C.S. acknowledge the assistance of the Spanish MCyT for the award of a FPU.

5 pages, 5 figures.-- Printed version published Oct 1, 2007., We present a novel synthetic method for the fabrication of encapsulated nanosized catalysts that have a core/shell structure consisting of numerous inorganic nanoparticles confined within the hollow core of a mesoporous carbon capsule. Specifically, we applied this synthetic strategy to CoFe2O4 nanoparticles (size ~10 nm), which were encapsulated within inner core of porous carbon capsules of ca. 350 nm diameter. We examined the catalytic activity of this core/shell catalytic composite toward H2O2 decomposition (Fenton reaction) and found that decomposition rates measured for this material were considerably higher than those for the unsupported nanoparticles and other nanocatalysts reported in the literature. The synthetic strategy described here could be extended to the preparation of other catalysts with similar core/shell structures., Financial support for this research work was provided by the Spanish MCyT (MAT2005-00262). T.V.S. thanks the CSIC-ISF for an I3P postdoctoral contract.

6 pages, 5 figures. -- Printed version published Dec 2007. -- Correction published in Catalysis Communications 9(15): 2621 (2008), http://hdl.handle.net/10261/11596, Spinel ferrite MnFe2O4 nanoparticles were synthesized by means of a nanocasting technique using a low-cost mesoporous silica gel as a hard template. The magnetic nanoparticles, of, T.V.-S. thanks the CSIC-ESF for the I3P postdoctoral contract. The financial support provided by MCyT (MAT2005-00262) and FICYT (IB05-001) is gratefully acknowledged.

7 pages, 4 figures, 1 table.-- Printed version published Apr 15, 2007., A nanosized LiMn2O4 (nano-LiMn2O4) spinel was prepared by a novel route using a porous silica gel as a sacrificial hard template. This material was found to be made up of 8–20 nm nanoparticles with a mean crystallite size of 15 nm. The electrochemical properties of nano-LiMn2O4 were tested in lithium cells at different cycling rates and compared to those of microsized LiMn2O4 (micro-LiMn2O4) obtained by the classical solid state route. Microsized LiMn2O4 is formed by 3–20 μm agglomerates, the size of each individual particle being approximately 0.20 μm. The behaviour of nano-LiMn2O4 as a positive electrode improves with increasing current densities (from C/20 to 2C). Moreover, it was found to exhibit a noticeably better performance at high rates (2C), with higher initial capacity values and very good retention (only 2% loss after 30 cycles), with respect to micro-LiMn2O4, almost certainly due to enhanced lithium diffusion in the small particles., Dr. Heiner Santner is thanked for his assistance in carrying out the electrochemical experiments. TVS thanks CSIC-ESF for the award of a postdoctoral I3P contract. The financial support for this research provided by the Spanish MCyT (MAT2005-00262) is gratefully acknowledged.

9 pages, 6 figures, 1 table.-- Available online Nov 2, 2006., By analogy with other types of carbons, templated mesoporous carbons (TMCs) can be used as supercapacitors. Their contribution arises essentially from the double layer capacity formed on their surface, which corresponds to 0.14 F m−2 in aqueous electrolytes such as H2SO4 and KOH and 0.06 F m−2 for the aprotic medium (C2H5)4NBF4 in CH3CN. In the case of a series of 27 TMCs, it appears that the effective surface area determined by independent techniques can be as high as 1500–1600 m2 g−1, and therefore exceeds the value obtained for many activated carbons (typically 900–1300 m2 g−1). On the other hand, the relatively low amount of surface oxygen in the present TMCs, as opposed to activated carbons, reduces the contribution of pseudo-capacitance effects and limits the gravimetric capacitance to 200–220 F g−1 for aqueous electrolytes. In the case of non-aqueous electrolyte, it rarely exceeds 100 F g−1., It is also shown that the average mesopore diameter of these TMCs does not improve significantly the ionic mobility compared with typical activated carbons of pore-widths above 1.0–1.3 nm., This study suggests that activated carbons remain the more promising candidates for supercapacitors with high performances., The financial support provided by the Spanish MCyT (MAT2005-00262) is gratefully acknowledged. M. Sevilla and S. Alvarez thank the Spanish MCyT for their respective FPU (AP-2004-0027) and FPI (BES-2003-0134) grants.

6 pages, 4 figures.-- Printed version published Sep 27, 2007., Highly graphitic carbon nanocoils were synthesised from the catalytic graphitization of carbon spherules obtained by the hydrothemal treatment of different saccharides (sucrose, glucose and starch). This nanostructured carbon was characterized by X-ray power diffraction, N2 adsorption and microscopy techniques (SEM and TEM). The carbon nanocoils were used as a support for PtRu nanoparticles, which were well-dispersed over the carbon surface. This catalytic system was investigated for use as an electrocatalyst for methanol electrooxidation in an acid medium. The experiments were carried out at two working temperatures (25°C and 60°C). It was found that the carbon nanocoils supporting PtRu nanoparticles exhibit a high catalytic activity, which is even higher than that of conventional carbon supports (Vulcan XC-72R). We believe that the high electrocatalytic activity of the carbon nanocoils presented here is due to the combination of a good electrical conductivity, derived from their graphitic structure, and a wide porosity that allows the diffusional resistances of reactants/products to be minimized., The financial support for this research work provided by the Spanish MCyT (MAT2005-00262) is gratefully acknowledged. MS acknowledges the assistance of the Spanish MCyT in awarding a FPU grant. G.A. acknowledges the financial support of the Polish grant DS 31-129/2007.

4 pages, 3 figures, 1 table.-- Available online Sep 26, 2006., A commercial macrocellular polyurethane foam was used as template to fabricate macro/mesoporous silica and carbon monoliths. These materials have a cellular structure which is a faithful replica of that of the polymeric foam. In addition, they have a high surface area and a large porosity made up of accessible mesopores. The synthesis of silica monoliths was carried out by impregnating the polymeric foam with a mixture of a silica precursor and a surfactant. The carbon monoliths were prepared by using the silica monoliths as sacrificial templates. They retain the foamy vesicular structure and exhibit a high surface area of 1800 m2 g−1 and a large porosity made up of framework-confined mesopores of around 3.4 nm., The financial support for this research work provided by the Spanish MCyT (MAT2005-00262) is gratefully acknowledged. S. Alvarez thanks the Spanish MCyT for her FPI (BES-2003-0134) grant.

7 pages, 4 figures.-- Available online on Oct 5, 2005., Graphitic porous carbons with a wide variety of textural properties were obtained by using a silica xerogel as template and a phenolic resin as carbon precursor. The synthetic procedure used to prepare them was as follows: (a) infiltration of the porosity of silica by a solution containing phenolic resin, (b) carbonization of the silica-resin composite, (c) removal of the silica skeleton, (d) impregnation of the templated porous carbon with a metallic salt and (e) catalytic graphitization of the impregnated carbon by heat treatment at 900°C. The graphitization of the carbons thus prepared varies as a function of the carbonization temperature used and the type of metal employed as catalyst (Fe, Ni or Mn). The porous characteristics of these materials change greatly with the temperatures used during the carbonization step. These graphitized carbons exhibit high electrical conductivities up to two orders larger than those obtained for the non-graphitized samples., The financial support for this research provided by the Spanish MCyT (MAT2005-00262) is gratefully acknowledged. MS acknowledges the assistance of the CSIC-ESF for the award of an I3P grant.

Publisher Summary This chapter presents the results of different tests for several candidate sorbents to be used in the 300–600° C temperature window. Special emphasis is placed on the analysis of the sulfation of sodium carbonate at different temperatures and sulfursulfursulfur dioxide (SO 2 ) concentrations. The observations indicate that several competing processes contribute to the sulfur capture of the tested sorbents. Simulation of boiler conditions is required for meaningful evaluations. From all tested sorbents, sodium carbonate presents the highest sulfur loading under the experimental conditions utilized. The sodium carbonate presents a maximum in sulfur capture of 0.66 mol SO 2 /mol sorbent at a temperature of 550 ° C. The sorbent is a good candidate to be utilized under economizer conditions. The change in SO 2 concentration between 900 and 3300 ppm does not have any influence on sulfur capture.

A study of the effect of coal preoxidation conditions (temperature and time) and particle size upon char structure has been performed. Two particle size ranges were studied: 125-180 and 710-1000 μm. Samples of a high-volatile bituminous coal were oxidized at 150 and 270°C for periods of time ranging from 6 hours to 15 days. Char porosity was examined by means of gas adsorption of CO 2 at 0°C and N 2 at -196°C. It was observed that chars from oxidized coals exhibit a CO 2 -micropore volume of around 0.18-0.25 cm 3 /g and an accessible micropore width of around 0.8 nm. Moreover, the oxidation process eliminates the constrictions in the entry of micropores. In this way, it was noted that the use of coal particles of 125-180 μm and a coal oxidation temperature of 270°C favours accessible char textural development.

The effects of air preoxidation of coal and flow rate of activating gas on the preparation of activated carbon were studied. A high-volatile bituminous coal was used as starting material. Coal preoxidation has a beneficial influence on the textural development of chars and activated materials. The flow rate of the activating gas (CO 2 ) has a big influence on the development of the porous network of the activated carbons. The best results were obtained with a high degree of coal preoxidation and a low flow rate of CO 2 in the activation step.

Publisher Summary This chapter discusses the influence of mineral matter on the structure and reactivity of chars. The composition of the organic matter is similar for all fractions. The use of narrow density intervals ensures that the particles within each individual fraction have similar ash content. The use of size-graded and density fractionated coal reduces the variability of parameters relevant to the combustion of char. Scanning electron microscopy of the six chars shows particles with a high plasticity, covered by reflectant matter identified as mineral particles. It is found that within the mineral areas, carbonaceous matter is present with features of plasticity. It is demonstrated that in the highest ash char, the amounts of calcium and particularly iron are considerably higher than in the lowest ash sample. The major part of iron is present as partly decomposed pyrite in the form of 1 μm particles. The highest ash fraction contains about six times as much FeS as the lowest ash char.

Publisher Summary This chapter discusses the structure and properties of unburned chars from fluidized bed coal combustion. Loss of char during fluidized bed combustion is a result of either elutriation of small flychar particles generated during coal devolatilization or of attrition of char with the bed materials. In a study described in the chapter, to improve combustion efficiency, the elutriated char was recycled to the bed or burned in another reactor. Therefore, process efficiency in fluidized bed combustion depends upon the efficient combustion of flychar. Flychar reactivity, measured isothermally at 500°C, decreased with the increase in combustion temperature. This trend is similar to that found for char reactivity with HTT during pyrolysis. The reactivity of flychars produced from semianthracite is hardly affected by the combustion temperature. The values of char reactivity measured isothermally correlate with the characteristic temperature derived from the burning profiles. A high proportion of the flychar consists of materials originated during the devolatilization stage. This proportion is higher for bituminous coals. The rest of the material is composed of more irregular structures, possibly formed during the reaction–attrition processes.

Publisher Summary Coal oxidation has an important influence on some relevant properties in relation with the coal beneficiation and utilization. This chapter discusses a study to examine the influence of coal oxidation on char reactivity. A high volatile bituminous A coal from the Maria Luisa mine in the North of Spain was used. Coal samples, ground to < 1mm, were placed in trays and oxidized in an oven with forced circulation of air at 413 K for different periods of time up to 72 h. Textural properties were obtained from the measurement of true (helium) and apparent (mercury) densities, total open pore volumes, and pore volume distributions. Coal preoxidation affects the textural properties of the chars subsequently obtained by pyrolysis. Coal preoxidation produces an important enhancement in the porosity of chars obtained by pyrolysis from oxidized samples of a bituminous coal.

The effect, on the preparation of activated carbons, of coal preoxidation, particle size and activating flow rate was studied. As starting material a high bituminous coal was used. Data on the progressive evolution of texture in oxidized coal samples, and in subsequent chars and activated material are presented. The flow rate of the activating agent (CO2) has a big influence on the development of the porous network of the activated carbons.