Quantification of the Imperfectness of the Molecular Flow Conditions of the Gas Entering the Mass Spectrometer Ion Source for Ionization: Exemplified for CO2 Isotope Amount Ratio Measurements

A new model to describe the gas flow status inside the gas mass spectrometer (MAT 271) inlet system has been developed and applied to the latest isotope amount ratio measurements.JRC.D.4-Isotope measurement

Iodine Doped Graphene for Enhanced Electrocatalytic Oxygen Reduction Reaction in PEM Fuel Cell Applications

Although doped graphene based materials have been intensively investigated, as electrocatalysts for oxygen reduction reaction (ORR), there is still a number of challenges to be explored in order to design a highly active, durable, thermodynamically stable and low-cost catalyst with full recognized technological importance. The application of iodine-doped graphene in fuel cells (FC) has been recently examined as innovative nanomaterial for cathode fabrication. Up to date microscopic and spectroscopic techniques have been combined with structural and electrochemical investigations for a compendious characterization of developed ORR catalysts. The unique structure of doped graphenes is ascertained by the presence of mesopores, vacancies and high surface area, and favors the ions/electrons transportation at nanometric scale. The chapter discusses (a) how to use the existing knowledge in respect to synthesized doped graphenes and (b) how to improve the FC by taking into account these materials and have an enhanced electrochemical performance as well as long-term durability

Determination by Isotope Ratio Mass Spectrometry of the Absolute Isotope Amount Fractions of Oxygen and Nitrogen in Nitrous Oxide

A measurement procedure for the complete isotope characterisation of atmospheric nitrous oxide sample has been developed and applied to establish a first Reference Material for this gas. The whole work has been based on the peculiar instrumental capabilites of "Avogadro" MAT 271IRMS. Additional hardware and software improvement has been done for this mass spectrometer to apply the proposed method.JRC.D.4-Isotope measurement

Steady State Isotopic Transient Kinetic Analysis Study of PEM Fuel Cell Anodes (SPA)

The hydrogen oxidation reaction at Proton Exchange Membrane Fuel Cell anodes is poisoned by part per million levels of carbon monoxide. Pt is the catalyst of choice for the oxidation of pure hydrogen, but it has recently been demonstrated that there is a dynamic equilibrium between CO adsorbed on Pt or Pt/Ru nanoparticles and CO in the gas phase, and that this equilibrium is affected by the competitive adsorption between CO and hydrogen. The purpose of this research is to perform Steady State Isotopic Transient Kinetic Analysis (SSITKA) experiments using the isotopic exchange between 13CO and 12CO to investigate the competitive adsorption of hydrogen and CO on commercial Pt and PtRu catalysts.JRC.D.4-Isotope measurement

Perovskite-Based Materials for Energy Applications

The role of energy in modern society is fundamental. Constraints due to the emissions of air pollutants from the excessive use of fossil fuels have increased dramatically in the last years. Over the years various devices and systems have been developed to transform energy from forms supplied by nature to forms that can be used by people. Another issue is to absorb energy generated at one time and to discharge it to supply power at a later time, what is called energy storage. This is also a matter to focus when it comes to searching for solutions of energy problems. Perovskites are promising key materials for energy applications, and in this chapter is a literature review summarizing the reported progress in energy applications of perovskite-type ceramic materials. To understand the fundamental nature of structure–property relationships, defect chemistry plays an important role. This paper, a mini-review, briefly describes from available literature and summarizes accordingly. It is focused on perovskite crystal structures, perovskite materials for solid oxide fuel cells, perovskite electrocatalyst and photocatalysts, and perovskite transport features

Perovskite-Type Lanthanum Cobaltite LaCoO₃: Aspects of Processing Route toward Practical Applications

Lanthanum cobaltite (LaCoO3) perovskite-type oxide is an important conductive ceramic material finding a broad range of technical applications. Physical and chemical properties of the final lanthanum cobalt oxide powder material obtained are strongly dependent on the method of preparation. Taking in account these considerations, we focus our investigation on the solid state reaction process. The characterization of prepared lanthanum cobalt oxide material was studied by using X-ray diffractometry (XRD), scanning electron microscopy (SEM), thermogravimetry-differential scanning calorimetry (TG-DSC), and conduction properties. Following the experimental results, it can be concluded that with proper improvement, the solid state reaction process may also provide an efficient preparation method for perovskite-type LaCoO3 powder. Important to mention is that we looked into the aspects to produce again same which showed consistently reproducibility of batch to batch powder properties. This is a key factor to overcome a successful commercialization of new material synthesis development

Noble Metal Dispersed on Reduced Graphene Oxide and Its Application in PEM Fuel Cells

Metal-dispersed nanoparticles on reduced graphene oxide as catalyst for oxygen reduction reaction (ORR) demonstrate promising applications in the energy sector. The catalyst activity enhancement and stability improvement investigated in this study are mandatory steps in obtaining feasible electrodes for PEMFC. The chapter deals with the synthesis of noble metal catalysts including platinum and gold nanoparticles dispersed on reduced graphene oxide (PtNPs/rGO and AuNPs/rGrO). The understanding of the correlations between the electrochemical activity on one side and the structure, composition and synthesis method on the other side are provided. Facile routes in order to prepare the well dispersed PtNPs/rGO and AuNPs/rGrO are included. The structure and morphology were characterized by different techniques, namely X-ray diffraction (XRD), Scanning Transmission Electron Microscopy (STEM), specific surface area measurements. In this context we report a hybrid derived electrocatalyst with increased electrochemical active area and enhanced mass-transport properties. The electrochemical performances of PtNPs/rGO and AuNPs/rGrO were tested and compared with a standard PEMFC configuration. The performed electrochemical characterization recommends the prepared materials as ORR electrocatalysts for the further fabrication of cathodes for PEM fuel cells. The research directions as well as perspectives on the subsequent development of more active and less expensive electrocatalysts are established

Applying the Direct Absorption Method and LSC for 14C Concentration Measurement in Aqueous Samples

From the 19th International Radiocarbon Conference held in Keble College, Oxford, England, April 3-7, 2006.We investigated a simple, reliable radiocarbon measurement procedure for water samples using the direct absorption method for sample preparation, followed by low-level liquid scintillation spectrometry. This process has involved quantitative evaluation of the conversion steps in order to estimate the appropriate working parameters. The 14C activity of dissolved inorganic carbon (DIC) for several types of water (ranging from seawater to groundwater) has been measured, paying attention to the preparation requirements of each type of water. The main advantage of this method is the simplified sample preparation, allowing measurement of a great number of samples in less time. This method was designed for routine analysis of water samples, and it is proposed particularly for use in 14C monitoring programs of CANDU-type reactors.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Experimental Results for an Off-Road Vehicle Powered by a Modular Fuel Cell Systems Using an Innovative Startup Sequence

This article deals with implementing a rule-based control method and startup sequence of a hybrid electric vehicle powered by a modular fuel cell system as its primary energy source and a lithium-ion battery system as its secondary energy source. The modular fuel cell system is composed of two separate fuel cell systems, electrically coupled to a one-power converter, using a programmable device. Depending on the vehicle’s operating mode, either both systems are used or just one of them. The vehicle’s fuel efficiency is improved by operating at constant power in the peak efficiency range of each fuel cell system. The experimental results show that the proposed system can significantly improve the fuel economy of a fuel cell vehicle and extend the driving range, while avoiding start/stop cycles. Additionally, this solution can increase the fuel cells’ lifecycle

Electronic Percolation Threshold of Self-Standing Ag-LaCoO3 Porous Electrodes for Practical Applications

Perovskite LaCoO 3 materials have various applications, from selective permeable membranes and gas sensing devices to water splitting applications. However, the intrinsic electrical resistivity of the perovskite limits the applicative potential. To overcome that, Ag powder was used with LaCoO 3 to obtain porous composite electrodes with enhanced conductivities. For that, a series of composite Ag-LaCoO 3 powders were prepared into pellets and pre-sintered at various temperatures up to 1000 ∘ C. Their structural properties and morphology were investigated by X-ray diffraction and scanning electron microscopy. The electronic transport of compacted specimens was studied by impedance spectroscopy. The results indicate that the presence of Ag acts as pre-sintering additive to obtain porous electrodes, with porosity values as high as 40% at 50 vol. % Ag. Moreover, the overall electrical resistivity of the composite electrodes varied well over four orders of magnitude. The results are discussed within the generalized Bruggeman theory for effective media comprising arbitrarily shaped metallic and semiconducting inclusions