Flexible ruthenium oxide-activated carbon cloth composites prepared by simple electrodeposition methods

This work focuses on the preparation of flexible ruthenium oxide containing activated carbon cloth by electrodeposition. Different electrodeposition methods have been used, including chronoamperometry, chronopotentiometry and cyclic voltammetry. The electrochemical properties of the obtained materials have been measured. The results show that the potentiostatic method allows preparing composites with higher specific capacitance than the pristine activated carbon cloth. The capacitance values measured by cyclic voltammetry at 10 mV s−1 and 1 V of potential window were up to 160 and 180 F g−1. This means an improvement of 82% and 100% with respect to the capacitance of the pristine activated carbon cloth. This excellent capacitance enhancement is attributed to the small particle size (4–5 nm) and the three-dimensional nanoporous network of the ruthenium oxide film which allows reaching very high degree of oxide utilization without blocking the pore structure of the activated carbon cloth. In addition, the electrodes maintain the mechanical properties of the carbon cloth and can be useful for flexible devices.Financial support by the Ministerio de Economía y Competitividad (MAT2010-15273) and Generalitat Valenciana and FEDER (PROMETEO/2009/047) projects are gratefully acknowledged. J.M.S. thanks Ministerio de Educación (SB2010-132)

Metal-free heteroatom-doped carbon-based catalysts for ORR. A critical assessment about the role of heteroatoms

Metal-free carbon-based catalysts have gained much attention during last years because of their interesting properties towards oxygen reduction reaction. Intrinsic parameters of carbon materials such as porosity, structural order, conductivity and defects have proved to have a strong influence in the catalytic activity of these materials. However, the highest differences in catalytic activity are obtained via doping with heteroatoms, being nitrogen the most remarkable in terms of activity and selectivity. One of the most challenging goals of the scientific community is to unravel the role of the functional groups in order to design an optimized material. However, the complexity of isolating one specific functionality, the difficult unambiguous characterization of the species and the influence of the intrinsic properties of the carbon materials, make the identification of the active sites a complex and controversial issue. This review presents a critical assessment about the role of heteroatoms on ORR from the analysis of the literature that combine both experimental work and computational modelling.The authors thank Ministerio de Ciencia, Innovación y Universidades and FEDER for financial support (Project RTI2018-095291-B-I00, ENE2017-90932-REDT and MAT2016-76595-R)

Tailoring Intrinsic Properties of Polyaniline by Functionalization with Phosphonic Groups

Phosphonated polyanilines were synthesized by copolymerization of aniline (ANI) with both 2- and 4-aminophenylphosphonic acids (APPA). The material composition and the final properties of the copolymers can be easily tailored by controlling the monomers ANI/APPA molar feed ratio. An important influence on the reactivity of monomers has been found with the substituent position in the ring, leading to differences in the properties and size of blocks of each monomer in the polymer. As expected, while 2APPA shows more similarities to ANI, 4APPA is much less reactive. Phosphorus loading of ~5 at% was achieved in the poly(aniline-co-2-aminophenylphosphonic acid) (PANI2APPA) with a 50/50 molar feed ratio. All the resulting copolymers were characterized by different techniques. Experimental results and density functional theory (DFT) computational calculations suggest that the presence of phosphonic groups in the polymeric chain gives rise to inter- and intra-chain interactions, as well as important steric effects, which induce a slight twist in the substituted PANI structure. Therefore, the physicochemical, electrical, and electrochemical properties are modified and can be suitably controlled.This research was funded by Ministerio de Ciencia e Innovación (Grant number: PID2019-105923RB-100) and Ministerio de Ciencia, Innovación y Universidades (grant number: FPU18/05127). And the APC was funded by Universidad de Alicante

Feasibility of electrochemical regeneration of activated carbon used in drinking water treatment plant. Reactor configuration design at a pilot scale

This work evaluates the feasibility of electrochemical regeneration of granular activated carbon used in drinking water treatment plants as a real alternative to thermal regeneration. Two pilot-plant-scale reactors, with a capacity of 10−15 kg, have been designed using two different configurations, parallel plate electrodes and concentric cylindrical electrodes. The optimization of the anode material has also been studied and Pt/Ti, RuO2/Ti and IrO2/Ti have been used. After the regeneration and, thus, recovery of the porosity the samples were tested in the adsorption of bisphenol A. In the electrochemical regeneration, recovery of the porosity of spent activated carbon until 100 % and 96 % with respect to the pristine activated carbon using Pt/Ti anode after 3 h of treatment, has been achieved. The regeneration process produces a small increase in the number of surface oxygen groups. No important differences have been observed among the tested anodes and RuO2/Ti and IrO2/Ti can be an economic alternative to Pt/Ti. Bisphenol A adsorption kinetics was slower in regenerated activated carbons probably due to the formation of surface oxygen groups. However, the adsorption capacity was similar in the regenerated samples and the pristine one.This work was supported by the European Union-Horizon 2020 (PORTABLECRAC - SPIRE09 - 2017 Nº 768905)

Polyaniline-Derived N-Doped Ordered Mesoporous Carbon Thin Films: Efficient Catalysts towards Oxygen Reduction Reaction

One of the most challenging targets in oxygen reduction reaction (ORR) electrocatalysts based on N-doped carbon materials is the control of the pore structure and obtaining nanostructured thin films that can easily be incorporated on the current collector. The carbonization of nitrogen-containing polymers and the heat treatment of a mixture of carbon materials and nitrogen precursor are the most common methods for obtaining N-doped carbon materials. However, in this synthetic protocols, the surface area and pore distribution are not controlled. This work enables the preparation of 2D-ordered N-doped carbon materials through the carbonization of 2D polyaniline. For that purpose, aniline has been electropolymerized within the porous structure of two different templates (ordered mesoporous Silica and ordered mesoporous Titania thin films). Thus, aniline has been impregnated into the porous structure and subsequently electropolymerized by means of chronoamperometry at constant potential. The resultant samples were heat-treated at 900 °C with the aim of obtaining 2D N-doped carbon materials within the template structures. Polyaniline and polyaniline-derived carbon materials have been analyzed via XPS and TEM and characterized by electrochemical measurements. It is worth noting that the obtained 2D-ordered mesoporous N-doped carbon materials have proved to be highly active electrocatalysts for the ORR because of the formation of quaternary nitrogen species during the heat treatment.This research was funded by Ministerio de Ciencia, Innovación y Universidades and FEDER grant number Project RTI2018-095291-B-I00 and ENE2017-90932-REDT

Effect of surface oxygen groups in the electrochemical modification of multi-walled carbon nanotubes by 4-amino phenyl phosphonic acid

Electrochemical functionalization of pristine Multi-walled Carbon Nanotubes (MWCNTs) and oxidized MWCNTs by nitric acid with 4-aminophenyl phosphonic acid (4-APPA) has been studied. Electrochemical modification has been carried out by cyclic voltammetry using different upper potential limits, what results in the incorporation of N and P functionalities through oligomerization and covalent attachment. The electrochemical characterization shows that there are important differences among the functionalized materials derived from the pristine MWCNTs or the oxidized materials. For the pristine MWCNTs, well-defined redox processes are observed. Characterization by X-Ray photoelectron spectroscopy, Raman spectroscopy and electron microscopy, show that oligomerization is easier for the pristine MWCNTs and the presence of oligomer chains are clearly distinguished for the lowest oxidation potentials. However, the presence of surface oxygen groups in the oxidized MWCNTs modify the interaction of the 4-APPA with the surface promoting mainly covalent attachment.The authors would like to thank MINECO and FEDER (MAT2016-76595-R) for the financial support. A.F.Q.J. gratefully acknowledges Generalitat Valenciana for the financial support through Santiago Grisolia grant (GRISOLIA/2016/084)

Hydrolytic Dehydrogenation of Ammonia Borane Attained by Ru-Based Catalysts: An Auspicious Option to Produce Hydrogen from a Solid Hydrogen Carrier Molecule

Chemical hydrogen storage stands as a promising option to conventional storage methods. There are numerous hydrogen carrier molecules that afford satisfactory hydrogen capacity. Among them, ammonia borane has attracted great interest due to its high hydrogen capacity. Great efforts have been devoted to design and develop suitable catalysts to boost the production of hydrogen from ammonia borane, which is preferably attained by Ru catalysts. The present review summarizes some of the recent Ru-based heterogeneous catalysts applied in the hydrolytic dehydrogenation of ammonia borane, paying particular attention to those supported on carbon materials and oxides.This work was financed by the MICINN, FEDER (RTI2018-095291-B-I00). MNG thanks the Plan GenT project (CDEIGENT/2018/027) for their financial support. DST thanks MICINN for the “Juan de la Cierva” contract (IJCI-2016-27636) and the Vicerrectorado de Investigación y Transferencia de Conocimiento de la Universidad de Alicante (GRE19-16)

Few layers graphene-based electrocatalysts for ORR synthesized by electrochemical exfoliation methods

Graphene-based materials were synthesized by electrochemical exfoliation method (cathodic method) starting from a graphite sheet. In the established methodology, an initial immersion in H2SO4 was applied, followed by cathodic expansion in potassium sulphate, where the effect of the applied voltage was studied. Finally, by ultrasound treatment, the exfoliation was achieved to produce a dispersion of few layer graphene material. Once the optimum procedure was established, Pt nanoparticles were incorporated using H2PtCl6.6H2O. This incorporation was studied at each stage of the graphene-based material synthesis to determine which was the most adequate to obtain the highest Pt dispersion and the best distribution of the Pt nanoparticles. In this sense, the incorporation of Pt in the graphene-based material colloidal dispersion by stirring for 3 h and sonication for 1 h, results in Pt nanoparticles with an average size of around 1 nm with an excellent distribution in the carbon material. The performance of this catalyst was compared with the commercial Pt/C electrocatalyst, showing a great oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) activity, exceeding it by far when comparing the mass-specific activity (A gPt−1) In addition, it presents excellent stability and selectivity toward the 4-electron pathway in ORR, which is the most energy-efficient, and using half of the platinum loading compared to the commercial material.The authors would like to thank PID2019-105923RB-I00 and PID2021-123079OB-I00 projects funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe”, and the Generalitat Valenciana (GRISOLIA/2020/114) for the financial support

Experimentació en síntesi química: química inorgànica

Aquest llibre de laboratori de química inorgànica està dirigit a alumnes que s'introdueixen per primera vegada en l'experimentació de síntesi inorgànica. Per aquest motiu, es pretén no sols que l'alumne adquiresca coneixements de química inorgànica sinó que els integre dins la metodologia de treball de la química inorgànica (els coneixements essencials de la qual són la teoria i l'experimentació).Secretariat de Normalització Lingüístic

Three-dimensional reconstruction using SFM for actual pedestrian classification

In recent years, the popularity of intelligent and autonomous vehicles has grown notably. In fact, there already exist commercial models with a high degree of autonomy as regards self-driving capabilities. A key feature for this kind of vehicle is object detection, which is commonly performed in 2D space. This has some inherent issues as an object and the depiction of such an object would be classified as the actual object, which is inadequate since urban environments are full of billboards, printed adverts and posters that would likely make these systems fail. In order to overcome this problem, a 3D sensor could be leveraged, although this would make the platform more expensive, energy inefficient and computationally complex. Thus, we propose the use of structure from motion to reconstruct the three-dimensional information of the scene from a set of images, and merge the 2D and 3D data to differentiate actual objects from depictions. As expected, our approach is able to work with a regular color camera. No 3D sensors whatsoever are required. As the experiments confirm, our approach is able to distinguish between actual pedestrians and depictions of them more than 87% of times in synthetic and real-world tests in the worst scenarios, while the accuracy is of almost 98% in the best case.This work was funded by a Spanish Government PID2019-104818RB-I00 grant, supported by Feder funds. It was also supported by Spanish grants for Ph.D. FPU16/00887. Experiments were made possible by a generous hardware donation from NVIDIA