Search

In this paper energy dispersive spectroscopy, X-ray diffraction and Williamson-Hall grain size/strain characterization techniques were used to determine the effect exhaust water electrical conductivity, heating and electrical current had on Proton Exchange Membrane electrocatalyst degradation and the underlying mechanism. Quartz containing polybenzimidazole polymer had 6 nm of platinum sputter-coated and while 50 to 400 cycles of either 0.7 mA or 30 mA current were applied. Results showed between 38% (overall) and 100% (locally) platinum removal using 0.7 mA (400 cycles) or 30 mA (50 cycles) using water with 5 vol% acetic acid. The acetic acid increased the water's electrical conductivity and helped transport quartz to the sample surface to interact with the platinum. This interaction increased quartz's lattice strain to 1.4% and resulted in detached platinum. Furthermore, similar results may occur using membranes formulated with acid side chains, which can leach during thermal decomposition and destroy stack performance. Image 1 • Heating >100 °C using water & acetic acid did not detach catalyst from membrane. • Electrical current, quartz & conductive water detached catalyst from membrane. • Electrically conductive water critical component to remove catalyst from membrane. • Larger electrical current magnitudes removed catalyst at faster detachment rates. • Mechanism involved diffusion of quartz & catalyst increasing quartz lattice strain. [ABSTRACT FROM AUTHOR]

A study is made on a proton exchange membrane (PEM) fuel cell that supports a new type of chemical coupling of 2-propanol/acetone/hydrogen to generate power. Power generation that uses this new chemical coupling of reactions requires specific types of catalysts in the fuel cell. In the present paper, investigations of a few catalysts and systematic metallic loading from different precursors in various loading ratios on carbon electrodes have been conducted to maximize current generation. Various permutations of catalysts (pure or composite) with different loading ratios were tested for their relative performance using chemical liquids as oxidants in the PEM fuel cell (reactor). The maximum electrical power obtained from a single layer of PEM fuel cell was 0.259 mW/cm2. Experimental results are promising and the new coupling of chemical reactions may be used successfully in the electrochemical reactor (fuel cell) to tap solar energy to generate power. Further work is needed to put this concept into reality for power generation from a solar assisted PEM fuel cell system. [ABSTRACT FROM AUTHOR]

Abstract: This paper analyzes the mechanism of deactivation of a new Cu–Al2O3–CuAl2O4 water–gas shift (WGS) catalyst recently developed for small-scale hydrogen generation applications, such as fuel cell-based residential power generators and hydrogen fueling stations. The catalyst has good potential for use in small-scale fuel processors working under essentially steady-state conditions, such as on-site hydrogen generation systems for hydrogen filling stations. However, transient regimes with frequent starts and stops of the fuel processing system, common for the residential fuel cell applications, can result in aging with a decline in activity of this (and most likely of any) copper-based WGS catalyst. The study described in this paper reveals that the aging resulting in deactivation of Cu–Al2O3–CuAl2O4 under start–stop conditions is due to passivation of the catalytically active surface by the dense shell of hydrogen-bonded hydroxides strongly adsorbed over copper oxide crystallites. This deactivation phenomenon, likely to be typical for all copper-based WGS catalysts operating with frequent starts and stops, is a serious issue that will likely prevent use of such catalysts in residential fuel cell applications. However, the deactivated Cu–Al2O3–CuAl2O4 catalyst can be regenerated by calcining in air, with full recovery of the activity. This regeneration, which is impossible for conventional copper–zinc–alumina catalysts, is a significant practical advantage and also supports the conclusion on the role of surface hydroxides in the deactivation mechanism. [Copyright &y& Elsevier]

The Energy System lab at the University of Trieste has carried out a study to investigate the reduction in performance of high temperature polymer electrolyte membrane (HTPEM) fuel cell membrane electrode assemblies (MEAs) when subjected to different ageing tests. In this study, start and stop cycles, load cycles, open circuit voltage (OCV) permanence and constant load profile were considered. Polarization curves (PC) together with electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) data were recorded during the ageing tests to assess the fuel cell performance. In this paper, experimental data are presented to confirm the test methodology previously proposed by the authors and to quantitatively correlate the performance degradation to the operational profiles. It was demonstrated that OCV condition, start and stop and load cycling increase degradation of the MEAs with respect to constant load operation. As expected, the OCV is the operational condition that influences performance degradation the most. Finally, the MEAs were analyzed with synchrotron small angle X-ray scattering (SAXS) technique at the Austrian SAXS beamline at Elettra-Sincrotrone Trieste to analyze the nano-morphological catalyst evolution. As for the catalyst morphology evolution, the ex situ SAXS methodology proposed by the authors is confirmed in its ability to assess the catalyst nanoparticles aggregation. [ABSTRACT FROM AUTHOR]

Synthesis gas production is a technology that dates to the 1950s. Recently, the conversion of hydrocarbons to syngas has played an important role in various applications from gas-to-liquid (GTL) processes to fuel cell applications. However, the current industrial production method is only profitable when large quantities of syngas are produced and generates high amounts of CO2 as a by-product. With the growing demands for smaller-scale and mobile syngas production technology, the catalytic partial oxidation of hydrocarbons has become a promising alternative to the conventional methane steam reforming technology. With the infrastructure for production and distribution of many commercial fuels already in place, numerous studies have been done on conversion of these fuels into syngas. This paper reviews the research that has been done in the past decade on the catalytic partial oxidation of conventional fuels and biofuels. The challenges faced in catalyst development are described as well as solutions that have been proposed to address those challenges. Advances in kinetic modelling of catalytic partial oxidation are presented, and techniques used to develop such models have also been highlighted. Finally, research gaps have been identified and recommendations have been given for further investigations to address current challenges. [ABSTRACT FROM AUTHOR]

One of the most attractive routes for the production of hydrogen or syngas for use in fuel cell applications is the reforming and partial oxidation of hydrocarbons. The use of hydrocarbons in high temperature fuel cells is achieved through either external or internal reforming. Reforming and partial oxidation catalysis to convert hydrocarbons to hydrogen rich syngas plays an important role in fuel processing technology. The current research in the area of reforming and partial oxidation of methane, methanol and ethanol includes catalysts for reforming and oxidation, methods of catalyst synthesis, and the effective utilization of fuel for both external and internal reforming processes. In this paper the recent progress in these areas of research is reviewed along with the reforming of liquid hydrocarbons, from this an overview of the current best performing catalysts for the reforming and partial oxidizing of hydrocarbons for hydrogen production is summarized. [ABSTRACT FROM AUTHOR]

Preferential oxidation of CO (CO‐PROX) in the hydrogen‐rich stream has been carried out over Pt‐NaY catalysts containing various Pt loadings along with Fe, Co, and Au. Catalysts have been characterized with inductively coupled plasma‐atomic emission spectroscopy, Brunauer, Emmett, and Teller surface area, X‐ray diffraction, transmission electron microscopy, X‐ray photoelectron spectroscopy, temperature programmed reduction, and Pt dispersion. CO‐PROX activities and CO oxidation selectivities are observed to increase with an increase in Pt content. Pt‐NaY catalyst with 0.75 wt.% Pt loading shows maximum CO‐PROX activity at low temperatures. An increase in space velocity decreases the CO and O2 conversions, but CO oxidation selectivity increases. A decrease in activity is observed when reformat gas contains around 20% H2O. During the stability test, no change in CO and O2 conversions is observed, but a small increase in the CO oxidation selectivity is noticed after 10 h indicating that the Pt‐NaY catalyst is a promising candidate for CO‐PROX reaction in a hydrogen‐rich stream. The Pt‐Fe‐NaY catalyst shows better activity than the Pt‐NaY catalyst but starts deactivating after 10 h. However, activity is observed to decrease over Pt‐Co‐NaY and Pt‐Au‐NaY catalysts. Pt‐Fe‐NaY catalyst with 0.75 and 0.35 wt.% Pt and Fe, respectively, shows better CO‐PROX activity at a temperature of 75°C. [ABSTRACT FROM AUTHOR]

Abstract: The present paper deals with the study on complete removal of CO in H2-rich gas stream through CO-SMET over Ru-based catalysts supported on γ-Al2O3 and CeO2 carriers. All the catalysts, loaded with 3% Ru, were prepared by a conventional impregnation method and their CO removal performance was determined at the powder level in a fixed bed micro reactor. The 3% Ru–γAl2O3 catalyst showed the best performance; consequently, it was deposited on microchannel metal plates reactor. With a catalyst load on the microchannel plates of 5mgcm−2 the performance was poor as complete CO conversion was not reached and also CO2 methanation was present. Increasing Ru load to 5%, the performance further worsened, the CO conversion decreased and higher amount of methane was produced. The catalytic activity on microchannel metal plates reactor was improved with the 3% Ru–γAl2O3 catalyst by doubling the its load on the surface (10mgcm−2): the residual CO concentration decreased to about 100–150ppmv at 310°C, but a large amount of methane was formed also by the CO2 methanation, thus reducing catalyst selectivity. [Copyright &y& Elsevier]

Abstract: The United States imports approximately 58% of its petroleum and about 2/3 of that is used for propulsion of cars and light trucks [The White House National Economic Council. Advanced Energy Initiative, http://www.whitehouse.gov/stateoftheunion/2006/energy/energy_booklet.pdf ; 2006]. It is important to reduce dependence on foreign oil. Hydrogen-fueled fuel cells for transportation have the potential to solve these problems. The US Department of Energy (DOE) is supporting research, development and demonstration of several types of fuel cells, including polymer electrolyte membrane (PEM) fuel cells, primarily for transportation applications. PEM technologies being developed with funding from DOE include electrolyte and membrane materials, catalyst and support materials, water management (including freeze/thaw) in the cell and stack, and bipolar plates. The effort is focused on the key issues of performance, durability, and cost. This paper provides an overview of the progress being made with DOE support. [Copyright &y& Elsevier]

Abstract: This paper presents the synthesis of Co-doped Al2O3 catalysts, developed by our group, with porous structures and high surface areas. The catalytic activity of the materials obtained was evaluated in the catalytic decomposition of methane, which is an attractive method for CO/CO2-free production of hydrogen, particularly for fuel cell applications. The catalysts were shown to be active and stable in relation to the catalytic decomposition of methane reaction. It was observed that the catalytic performance is dependent on the catalyst characteristics and on the operational conditions employed. The conversion of methane increased with metal loading, reaction temperature and N2:CH4 molar ratio. [Copyright &y& Elsevier]

On board hydrogen production out of hydrocarbons (reforming) for fuel cells feed is subject to problems when used with traditional catalysts. High device weight, a relatively long transient time and poisoning problems make the integration onboard a vehicle complex. In response to these challenges, hydrocarbons reforming processes assisted by non-thermal plasmas for hydrogen production have been implemented over recent years. This paper aims to provide an overview of the setting up, feasibility and efficiency of the existing technologies here investigated. This state-of-the-art technology review explains the key characteristics of plasma reforming through various original approaches. The performances of some of the systems are then compared against each other and discussed. [Copyright &y& Elsevier]

Abstract: The ideal fuel for PEMs and SOFC fuel cells is pure hydrogen, which is not available in nature and thus needs to be produced from other resources. It is a special task to make hydrogen from JP-8 (kerosene-based jet propulsion fuel), which consists of high hydrocarbon and aromatic compounds, as well as contains a significant amount of sulfur (up to 3000ppm). The auto-thermal reforming (ATR) process is externally energy-intensive and cost-effective method for hydrogen generation. However, it is critical to develop highly efficient, low-cost catalyst. This paper presents a detailed description of a novel combustion approach for synthesis of complex LaFeO3-based catalysts. The activities of these catalysts for ATR of JP-8 fuel were also tested in unique Micro-Scale Bench-Top Reactor System. Several non-noble (Me=K, Na, Li, Cs, Co, Mo) and noble metals additives (Me=Pt, Pd, Ru, Re) were tested as B-site substitution in La0.6Ce0.4Fe0.8−Z Ni0.2Me Z O3−δ perovskite to find the compositions that possess stable and effective performance under severe sulfur containing environment. It was shown that small amounts of potassium (2wt.%) or ruthenium (1wt.%) doped to above perovskite structure significantly increase catalysts activity and lead to their stable performance during reforming of JP-8 fuel with up to 220ppm of sulfur. [Copyright &y& Elsevier]

Abstract: In this paper, the effect of the catalyst surface site density (catalyst amount) and reactor geometry on the reforming process of methane in a wall-coated, single-channel microreactor is investigated numerically. Such a reactor, consisting of a tubular flow channel and a thermal conductive channel wall, is a good representation of microfabricated channels and monoliths. It is found that the hydrogen selectivity changes significantly with varying catalyst loading, which is a noteworthy result. Thus, the reaction path leading to higher hydrogen production becomes more important by increasing the catalyst surface site density on the active surface. This is due to the splitting rate of methane and water, which is a function of catalyst density. Furthermore, this study shows the significance of scaling the inlet volume flow not only with the reactor volume (gas space velocity) but also with the catalyst amount (catalyst space velocity). Another unexpected result is the presence of an optimum channel geometry and an optimum catalyst amount if the gas space velocity and the catalyst space velocity are constant. This underlines the necessity of coordinating the channel diameter, the inlet volume flow rate, and the catalyst amount in order to obtain a maximum reformer performance. Furthermore, it is necessary to specify the catalyst amount, the inlet conditions and the geometry in order to characterize sufficiently a catalytic reactor. [Copyright &y& Elsevier]

Abstract: Fuel cell requires hydrogen as its fuel source for generating power. Hydrogen for use in auxiliary power units is produced in a fuel processor by the catalytic reforming of hydrocarbons. Diesel, jet fuel, gasoline, as well as natural gas, are potential fuels that all have existing infrastructure of manufacture and distribution, for hydrogen production for fuel cell applications. It is well known that essentially all hydrocarbon feeds contain sulfur at different concentrations. In addition to coking, sulfur poisoning is the main force for deactivation of pre-reforming and reforming catalysts. The objective of this paper is to develop, test and characterize efficient catalysts for hydrogen generation from diesel autothermal reforming. Bimetallic catalysts exhibited superior performance compared to the commercial catalyst and the monometallic counterparts. BET, TPD, TPR, and XPS were utilized for surface analysis of these formulations, which showed that the enhanced stability is due to a strong metal–metal and metal–support interaction in the catalyst. [Copyright &y& Elsevier]

Examples of the merits of blue-sky research in the history of science are legion. The invention of the laser, celebrating its 50th anniversary this year, is an excellent example. When it was invented it was considered to be ''a solution waiting for a problem'', and yet the level to which it has now infiltrated our day-to-day technological landscape speaks volumes. At the same time it is also true to say that the direction of research is also at times rightly influenced by the needs and concerns of the general public. Over recent years, growing concerns about the environment have had a noticeable effect on research in nanotechnology, motivating work on a range of topics from green nanomaterial synthesis [1] to high-efficiency solar cells [2] and hydrogen storage [3]. The impact of the world''s energy consumption on the welfare of the planet is now an enduring and well founded concern. In the face of an instinctive reluctance to curtail habits of comfort and convenience and the appendages of culture and consumerism, research into renewable and more efficient energy sources seem an encouraging approach to alleviating an impending energy crisis. Fuel cells present one alternative to traditional combustion cells that have huge benefits in terms of the efficiency of energy conversion and the limited harmful emissions. In last week''s issue of Nanotechnology, Chuan-Jian Zhong and colleagues at the State University of New York at Binghamton in the USA presented an overview of research on nanostructured catalysts in fuel cells [4]. The topical review includes insights into the interactions between nanoparticles and between nanoparticles and their substrate as well as control over the composition and nanostructure of catalysts. The review also serves to highlight how the flourishing of nanotechnology research has heralded great progress in the exploitation of catalysts with nanostructures ingeniously controlled to maximize surface area and optimize energetics for synthesis procedures. One man who was well aware of the role of nanostructured catalysts in the progress of material science research was the late Ulrich Gosele, director at the Max-Planck-Institut fur Mikrostrukturphysik Halle, who passed away at the age of 60 on 8 November, 2009. Ulrich Gosele published over 750 papers of premium calibre research that have collectively been cited over 20,000 times. His research output includes a cornucopia of excellent work published in Nanotechnology, amongst which are a number of papers detailing the deft manipulation of nanocatalysts to control the quality and structure of nanomaterials [5-8]. Ulrich Gosele was a pioneer in nanoscience. In 1991, when the nanotechnology revolution was little more than a portentous rumble, he published a seminal report examining the effect of quantum confinement on the optical properties of silicon nanowires [9]. While we lament the loss to the community, we have much to celebrate in the insights his legacy has provided for the progress of materials science. It would be unwise to assume that science will or can ultimately advance in such a way as to allow ample means to indulge an unrestrained appetite for consumerism and energy consumption. As with most things, a balanced approach, considering solutions to the problem from many angles, seems sensible. Nonetheless, a browse through the latest literature leaves much cause for optimism for the positive role science can play in improving and sustaining our lifestyle. References [1] Mukherjee P, Roy M, Mandal B P, Dey G K, Mukherjee P K, Ghatak J, Tyagi A K and Kale S P 2008 Nanotechnology 19 075103 [2] Greenham N C and Gratzel M 2008 Nanotechnology 19 420201 [3] Vajo J, Pinkerton F and Stetson N 2009 Nanotechnology 20 200201 [4] Zhong C-J, Luo J, Fang B, Wanjala B N, Njoki P N, Loukrakpam R and Yin J 2010 Nanotechnology 21 062001 [5] Sivakov V A, Scholz A, Syrowatka F, Falk F, Gosele U and Christiansen S H 2009 Nanotechnology 20 405607 [6] Liu L, Lee W, Huang Z, Scholz R and Gosele U 2008 Nanotechnology 19 335604 [7] Fan H J et al 2006 Nanotechnology 17 S231-9 [8] Stelzner Th et al 2006 Nanotechnology 17 2895-8 [9] Lehmann V and Gosele U 1991 Appl. Phys. Lett. 58 856-8 [ABSTRACT FROM AUTHOR]

The performance of a СuO-ZnO/γ-AlO catalyst for the reactions of methanol, dimethyl ether (DME) and dimethoxymethane (DMM) steam reforming (SR) to hydrogen-rich gas was studied. The catalyst was found to be active and selective for methanol and DMM SR producing hydrogen-rich gas with low content of CO (<1 vol %). It provided complete conversion of methanol and DMM at 300°C, and hydrogen productivity of, respectively, 15 and 16.5 Lgh. With the use of physicochemical methods and catalytic experiments, it was shown that the catalyst surface contained the acid sites typical for γ-AlO, and CuO-ZnO agglomerates, responsible, respectively, for DMM hydration to methanol and formaldehyde, and SR of these compounds to hydrogen-rich gas. [ABSTRACT FROM AUTHOR]

Fuel cells are very promising technologies for efficient electrical energy generation. The development of enhanced system components and new engineering solutions is fundamental for the large-scale deployment of these devices. Besides automotive and stationary applications, fuel cells can be widely used as auxiliary power units (APUs). The concept of a direct methanol fuel cell (DMFC) is based on the direct feed of a methanol solution to the fuel cell anode, thus simplifying safety, delivery, and fuel distribution issues typical of conventional hydrogen-fed polymer electrolyte fuel cells (PEMFCs). In order to evaluate the feasibility of concrete application of DMFC devices, a cost analysis study was carried out in the present work. A 200 W-prototype developed in the framework of a European Project (DURAMET) was selected as the model system. The DMFC stack had a modular structure allowing for a detailed evaluation of cost characteristics related to the specific components. A scale-down approach, focusing on the model device and projected to a mass production, was used. The data used in this analysis were obtained both from research laboratories and industry suppliers specialising in the manufacturing/production of specific stack components. This study demonstrates that mass production can give a concrete perspective for the large-scale diffusion of DMFCs as APUs. The results show that the cost derived for the DMFC stack is relatively close to that of competing technologies and that the introduction of innovative approaches can result in further cost savings. [ABSTRACT FROM AUTHOR]

Preparation of hydrogen by low-temperature steam conversion of ethanol on nickel and binary nickel-copper catalysts supported on zinc oxide was studied experimentally in the temperature interval 200-450°C. High efficiency of hydrogen evolution in the course of ethanol conversion on these catalysts was demonstrated. At temperatures lower than 350°C, the main conversion products are hydrogen, methane, carbon monoxide, and carbon dioxide. At 400°C, the conversion products contain no carbon monoxide, which allows the mixture obtained to be used for feeding fuel cells with proton-conducting membranes. [ABSTRACT FROM AUTHOR]

As a provider of our energy requirements, hydrogen seems to be one of most promising fuels, in particular when used to feed PEM fuel cells. When produced from a renewable source, it has got the potential to reduce the dependence on non-renewable fossil fuels and lower the amount of harmful emissions. Ethanol steam-reforming (ESR) reaction is an interesting option to obtain a H- and CH-rich stream with a low content of CO, combining the deep knowledge of the technology with the advantage of the biomass-derived feedstock. Thermodynamic analysis has indicated that the most interesting operating range to enhance the H production and minimize CO and coke formation requires low pressure, high temperature, and high water-to-ethanol molar ratio. On the other hand, despite its endothermic nature, ESR could be carried out at low temperature, to increase overall thermal efficiency, even if at these conditions the catalyst's deactivation, due to coking and sintering phenomena, is not negligible. The main objective of this study is to investigate on the activity, stability, and durability of bimetallic Pt-Ni and Pt-Co catalysts supported on CeO for low-temperature bio-ESR reaction. The catalysts have been prepared through different methods and with an optimized metal's content. They have also been characterized with various physico-chemical characterization tests, and the catalytic studies have been carried out in a lab-scale apparatus. While evaluating the effects on the catalysts' performances of preparation method, reaction temperature, space time, and water-to-ethanol molar ratio, the selected catalysts were found effective for the production of H by steam reforming at low temperature. In particular, the Pt/Ni/CeO catalyst shows a perfect agreement with equilibrium calculations yet at low contact times, although some carbon deposition occurs. Also the cobalt-based catalysts appear attractive. The relative rates of carbon growth versus gasification have been studied, and ascending water contents were used to study the effect of steam addition in the feed stream. An in-depth investigation of the reaction mechanism and the evaluation of the kinetic parameters will be crucial to complete the study of the proposed process. [ABSTRACT FROM AUTHOR]

Studies are presented of the kinetics and mechanism of oxygen electroreduction on CoPd catalysts synthesized on XC 72 carbon black. As shown both in model conditions and in tests with the cathodes of hydrogen–oxygen fuel cells with proton conducting electrolyte, the CoPd/C system features higher activity as compared to Co/C. It is found by means of structural analysis that CoPd alloy is formed in the course of the catalyst synthesis. This provides the higher catalytic activity of the binary systems. CoPd/C catalyst is also more stable in respect to corrosion than Pd on carbon black. Measurements on a rotating ring–disc electrode show that the CoPd/C system provides preferential oxygen reduction to water in the practically important range of potentials ( E > 0.7 V). The similarity of the kinetic parameters of the oxygen reduction reaction on CoPd/C and Pt/C catalysts points to a similar reaction mechanism. The slow step of the reaction is the addition of the first electron to the adsorbed and previously protonated O2 molecule. Studies of the most active catalyst in the fuel cell cathodes are performed. Binary PtCo catalysts (metal atomic ratio of 1 : 1) with low platinum content (7.3 wt.%) modified by phosphorus or sulfur are developed and studied. It is demonstrated that the specific activity of the PtCoS/C (Pt : S = 1 : 1) catalytic system for the O2 reduction reaction exceeds that of a commercial Pt/C catalyst (E-TEK). The tolerance of the catalyst modified with sulfur is at least six times higher than that of Pt/C (E-TEK). [ABSTRACT FROM AUTHOR]

In a hydrogen-based energy system, fuel cells will utilize hydrogen to produce electricity while reformers produce hydrogen from infrastructure fuels, such as gasoline, diesel and natural gas. Reformers based on microchannel technology require a catalyst dispersed throughout a porous support, and the support must adhere firmly to the substrate. In this work, catalyst and support precursors were deposited via plasma enhanced chemical vapor deposition onto Fecralloy substrates, in alternate layers of plasma-polymerized platinum acetylacetonate and zirconium acetylacetonate. Non-equilibrium, inductively-coupled plasma was generated by applying radio frequency fields to a precursor vapor plume emanating from a heated sublimator crucible. After calcining the composite organic film to volatilize organic constituents, catalytically active platinum agglomerates remained supported by a matrix of zirconia. Plasma-processing took place directly in precursor vapor without added carrier gas. The intermediate organic composite film and the final synthesized platinum-loaded support adhering to the Fecralloy have been evaluated with profilometry, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and inductively coupled plasma-mass spectrometry. Cubic phase platinum and cubic phase zirconia have been detected on the Fecralloy. This material catalyzes conversion of carbon monoxide to carbon dioxide in a water gas shift (WGS) reactor in the temperature range 400 °C-500 °C. [ABSTRACT FROM AUTHOR]

The increasing energy demand and the subsequent climate change consequences are supporting the search for sustainable alternatives to fossil fuels. In this scenario, the link between hydrogen and renewable energy is playing a key role and unitized hydrogen-chlorine (H2-Cl2) regenerative cells (RFCs) have become promising candidates for renewable energy storage. Described herein are the recent advances in cell configurations and catalysts for the different reactions that may take place in these systems, that work in both modes: electrolysis and fuel cell. It has been found that platinum (Pt)-based catalysts are the best choice for the electrode where hydrogen is involved, whereas for the case of chlorine, ruthenium (Ru)-based catalysts are the best candidates. Only a few studies were found where the catalysts had been tested in both modes and recent advances are focused on decreasing the amount of precious metals contained in the catalysts. Moreover, the durability of the catalysts tested under realistic conditions has not been thoroughly assessed, becoming a key and mandatory step to evaluate the commercial viability of the H2-Cl2 RFC technology. [ABSTRACT FROM AUTHOR]