CO2-free Hydrogen Research Articles

P2G System Technology Development Aiming at Building a CO2-Free Hydrogen Society

The government's "Basic Energy Plan" decided on April 11, 2014 has been decided to promote initiatives aimed at realizing "hydrogen society", a society that utilizes hydrogen in everyday life and industrial activities It was. Following this, the Ministry of Economy, Trade and Industry will formulate the "Hydrogen / Fuel Cell Strategy Roadmap" in June 2014 and aim to establish a CO2-free hydrogen supply system around the year 2040. According to the Government's "Long-Term Energy Supply and Demand Outlook" published in July 2015, the renewable energy ratio to total electricity generation in FY 2030 is estimated to be 22 to 24%. On the other hand, renewable energy has large output fluctuations due to the influence of the natural environment, and geographically unevenly, there are concerns such as suspension of connection to the transmission and distribution electric power network. One solution to this problem would be the Power-to-Gas system utilizing the conversion using electric power from renewable energy into hydrogen. The obtained hydrogen can reduce CO2 emissions by replacing fossil fuels in heating sector. At the Agency for Natural Resources and Energy, the report of the "CO2 Free Hydrogen Working Group" was compiled in March, In the report, technical issues such as low cost and high efficiency of various technologies including water electrolysis equipment, improvement of durability, improvement of utilization rate were taken as technical issues. In this research, we demonstrate technological development from hydrogen production using renewable energy to transportation, storage and use in the real society, and establish the basic technology for practical application of "Power to Gas system". The applicability of the water electrolyzer was confirmed by grasping the electrical characteristics of the water electrolyzer (the ability to absorb unstable power, responsiveness, etc.) from the data of the evaluation equipment. In addition, it was expected that 74% could be achieved with the year-round water electrolyzer system efficiency. In the future business model using the 1.5 MW PEM type water electrolyzer, the MEA performance for achieving the required system efficiency of 80.5% is based on the voltage efficiency has already been achieved. Assuming a system at the stage of practical use, we concluded that direct utilization for industrial use and utilization as a CO2-free fuel for the heat demand for industrial use are effective. In line with this conclusion, we have determined the specifications of a pure hydrogen boiler assumed as a hydrogen utilization device, by investigating the tolerance of fluctuations and the partial load operation in line with actual plant operation. ACKNOWLEDGEMENT This work was partially supported by the New Energy and Industrial Technology Development Organization (NEDO) of Japan.

Hydrogen technologies and developments in Japan

Abstract The successful development of hydrogen-energy technologies has several advantages and benefits. Hydrogen-energy development could prevent global warming as well as ensure energy security for countries without adequate energy resources. The successful development of hydrogen would provide energy for transportation and electric power. It is a unique energy carrier, as it can be produced from various energy sources such as wind, fossil fuels and biomass and, when it is combusted, it emits no CO2 emissions. The other advantage is the wide distribution of resources globally that can be used to produce hydrogen. In Japan, the Ministry of Economy, Trade and Industry (METI) published a ‘Strategic Roadmap for Hydrogen and Fuel Cells’ in 2014, with a revised update published in March 2016. The goal of the roadmap is to achieve a hydrogen society. The roadmap aims to resolve technical problems and secure economic efficiency. The roadmap has been organized into the following three phases: Phase 1—Installation of fuel cells; Phase 2—Hydrogen power plant/mass supply chain; Phase 3—CO2-free hydrogen. This paper reports on the current status of fuel cells and fuel-cell vehicles in Japan and gives a description and status of the R&D programmes along with the results of global energy model study towards 2050.

Energy Efficient and Intermittently Variable Ammonia Synthesis over Mesoporous Carbon-Supported Cs-Ru Nanocatalysts

The Cs-promoted Ru nanocatalysts supported on mesoporous carbon materials (denoted as Cs-Ru/MPC) and microporous activated carbon materials (denoted as Cs-Ru/AC) were prepared for the sustainable synthesis of ammonia under mild reaction conditions (<500 °C, 1 MPa). Both Ru and Cs species were homogeneously impregnated into the mesostructures of three commercial available mesoporous carbon materials annealed at 1500, 1800 and 2100 °C (termed MPC-15, MPC-18 and MPC-21, respectively), resulting in a series of Cs-Ru/MPC catalysts with Ru loadings of 2.5–10 wt % and a fixed Cs loading of 33 wt %, corresponding to Cs/Ru molar ratios of 2.5–10. However, the Ru and Cs species are larger than the pore mouths of microporous activated carbon (shortly termed AC) and, as a consequence, were mostly aggregated on the outer surface of the Cs-Ru/AC catalysts. The Cs-Ru/MPC catalysts are superior to the Cs-Ru/AC catalyst in catalysing mild ammonia synthesis, especially for the 2.5Cs-10Ru/MPC-18 catalyst with a Ru loading of 10 wt % and a Cs/Ru ratio of 2.5, which exhibited the highest activity across a wide SV range. It also showed an excellent response and stability during cycling tests over a severe temperature jump in a short time, presumably due to the open mesoporous carbon framework and suitable surface concentrations of CsOH and metallic Ru species at the catalytically active sites. This 2.5Cs-10Ru/MPC-18 catalyst with high activity, fast responsibility and good stability has potential application in intermittently variable ammonia synthesis using CO2-free hydrogen derived from electrolysis of water using renewable energy with fast variability.

Module design of silica membrane reactor for hydrogen production via thermochemical IS process

The potential of the silica membrane reactors for use in the decomposition of hydrogen iodide (HI) was investigated by simulation with the aim of producing CO2-free hydrogen via the thermochemical water-splitting iodine-sulfur process. Simulation model validation was done using the data derived from an experimental membrane reactor. The simulated results showed good agreement with the experimental findings. The important process parameters determining the performance of the membrane reactor used for HI decomposition, namely, reaction temperature, total pressures on both the feed side and the permeate side, and HI feed flow rate were investigated theoritically by means of a simulation. It was found that the conversion of HI decomposition can be improved by up to four times (80%) or greater than the equilibrium conversion (20%) at 400 °C by employing a membrane reactor equipped with a tubular silica membrane. The features to design the membrane reactor module for HI decomposition of the thermochemical iodine-sulfur process were discussed under a wide range of operation conditions by evaluating the relationship between HI conversion and number of membrane tubes.

Techno-economic analysis of a potential energy trading link between Patagonia and Japan based on CO2 free hydrogen

Abstract With regard to the Fukushima Daiichi accident in 2011 and Japan's goal to reduce CO2 emission, the Japanese government strives for an emission free “hydrogen society” in which hydrogen will be the primary energy medium. The import of hydrogen generated by means of CO2 free wind electricity from overseas can be a promising option for Japan's prospective energy supply. Besides different other factors like specific costs of electrolyzers and hydrogen shipment over long distances, the economically reasonable export of hydrogen based on renewable energy requires low levelized costs of electricity. Within the scope of this study, the underlying idea of a hydrogen supply chain is taken up and revisited by means of a spatially highly resolved wind energy potential analysis and a detailed investigation of the supply chain elements between Patagonia and Japan. Our analysis reveals that approximately 25% of the total land area in Patagonia would be eligible. Approx. 33,000 turbines with a minimum number of 4500 full-load hours with an overall capacity of about 115 GW can be positioned. Taking into consideration the related average number of 4750 full-load hours and an electrolysis efficiency of 0.7, this leads to a potential production of about 11.5 million tons/year of hydrogen. So the wind power potential of Patagonia would theoretically be sufficient for the assumed Japanese hydrogen demand of 8.83 million tons/year. The total hydrogen pretax cost would amount to approx. 4.40 €/kgH2 at a liquid state at the harbor of Yokohama. Hence, the final specific costs of hydrogen in Japan depend on the expansion of wind power in Patagonia and therefore hydrogen based on wind energy can be cost-competitive to conventional fuels.

Establishment of Blue Energy Center and Its Future Development

A research center focusing on salinity gradient energy (SGE), “Blue Energy center for SGE Technology (BEST)”, was newly established in Yamaguchi University in July 2018. This center is forging ahead membrane–based researches utilizing SGE towards its future’s implementation. In BEST, there are three research groups: (1) SGE conversion group, (2) Water hydrolysis group and (3) Water treatment group. Here, we introduced one of BEST ’s researches, a direct hydrogen production technique from seawater and sewage treated water by reverse electrodialysis (RED–H2 system). Since Yamaguchi is one of innovative prefectures for hydrogen applications, there is a good opportunity to generate CO2–free hydrogen (and oxygen) by the RED–H2 system at the municipal wastewater plant especially in Shunan city.

Methane Pyrolysis for Carbon Nanotubes and COx-Free H2 over Transition-Metal Catalysts

Recently, researchers at West Virginia University reported a promising catalyst innovation for nonoxidative thermochemical conversion of methane to CO2-free hydrogen and solid carbon nanotubes (CNTs). A catalyst system was discovered that promotes “base growth” CNT formation rather than conventional “tip growth”. This enables catalyst regenerability while also generating highly pure and crystalline carbon products. In this study, simultaneous productions of CNTs and CO2-free hydrogen were studied over Fe-based catalysts supported on Al2O3, SiO2, and H-ZSM-5. The experimental results showed that metal–support interaction played a key role in the base growth mechanism. Methane conversion and the property of CNTs depended significantly on metal loading and the type of support. To elucidate the formation mechanism of CNTs, the spent catalysts were characterized by a number of analytical instrumentations including transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD)...

R&D status of hydrogen production test using IS process test facility made of industrial structural material in JAEA

Abstract Thermochemical water splitting by means of the iodine-sulfur (IS) process is one of the promising candidates of CO2-free hydrogen production. Japan Atomic Energy Agency (JAEA) has been conducting R&D on the IS process since the end of the 1980s. A test facility has been constructed using corrosion-resistant industrial structural materials to verify the integrity of chemical plant components and demonstrate continuous and stable hydrogen production. A trial operation was successfully carried out for 8 h with a hydrogen production rate of approximately 10 NL/h. To improve the facility for enhancing the operation stability, a shaft seal technology was developed for a corrosion-resistant pump, which is the key device for feeding HI solution with high concentrations of iodine. The shaft seal technology features purge gas supply and solvent supply to the shaft seal part of the pump to prevent I2 precipitation, which causes pump malfunction. Upon introduction of the developed shaft seal technology, the duration of the hydrogen production operation was extended to 31 h (hydrogen production rate of approximately 20 NL/h).

A quantitative analysis of Japan's optimal power generation mix in 2050 and the role of CO2-free hydrogen

In this study, the authors developed an Optimal Power Generation Mix model, which takes into account the supply chain of imported and domestically produced hydrogen, also modeling the intermittency of renewable energy at a 10-min resolution, and applied it to the case of Japan, to investigate quantitatively the possibility of achieving zero emission in 2050. Even if the costs of wind and solar PV decline drastically towards 2050 and the huge potentials that have been assumed in the literature are realized, the total system costs escalate significantly with very high shares of intermittent renewables. Since the use of hydrogen produced by excess electricity from renewable power generation sources can only make a slight contribution to reducing this escalation, it would be invaluable to introduce at least a significant amount of electricity generated by “zero-emission thermal power” technologies, including CO2-free imported hydrogen or conventional thermal power generation with carbon capture and sequestration (CCS). Nuclear power is also estimated as being effective in reducing the cost hike associated with achieving zero emissions. The results of this study could contribute to giving insights regarding global deployment of hydrogen-related technologies, as well as to presenting a frame of reference for Japan's future energy policies.

P2G System Technology Development Aiming at Building a CO2-Free Hydrogen Society

The government's "Basic Energy Plan" decided on April 11, 2014 has been decided to promote initiatives aimed at realizing "hydrogen society", a society that utilizes hydrogen in everyday life and industrial activities It was. Following this, the Ministry of Economy, Trade and Industry will formulate the "Hydrogen / Fuel Cell Strategy Roadmap" in June 2014 and aim to establish a CO2-free hydrogen supply system around the year 2040. According to the Government's "Long-Term Energy Supply and Demand Outlook" published in July 2015, the renewable energy ratio to total electricity generation in FY 2030 is estimated to be 22 to 24%. On the other hand, renewable energy has large output fluctuations due to the influence of the natural environment, and geographically unevenly, there are concerns such as suspension of connection to the transmission and distribution electric power network. One solution to this problem would be the Power-to-Gas system utilizing the conversion using electric power from renewable energy into hydrogen. The obtained hydrogen can reduce CO2 emissions by replacing fossil fuels in heating sector. At the Agency for Natural Resources and Energy, the report of the "CO2 Free Hydrogen Working Group" was compiled in March, In the report, technical issues such as low cost and high efficiency of various technologies including water electrolysis equipment, improvement of durability, improvement of utilization rate were taken as technical issues. In this research, we demonstrate technological development from hydrogen production using renewable energy to transportation, storage and use in the real society, and establish the basic technology for practical application of "Power to Gas system". ACKNOWLEDGEMENT This work was partially supported by the New Energy and Industrial Technology Development Organization (NEDO) of Japan.

Special issue: Plasma Conversion

With growing concern of energy and environmental issues, the combination of plasma and heterogeneous catalysts receives special attention in greenhouse gas conversion, nitrogen fixation and hydrocarbon chemistry. Plasma gas conversion driven by renewable electricity is particularly important for the electrification of the chemical industry, which is currently dominated by water electrolysis, producing CO2-free renewable hydrogen. Meanwhile, electrochemical conversion of CO2, CH4 and other gaseous materials has yet to be successful because the material and energy conversion efficiency as well as productivity of the electrochemical processes greatly depend on the electrolyte material in terms of the solubility of gaseous materials and mass transport capability, which needs to be dramatically improved. As for fuel processing, the majority of reactions are categorized as uphill (endothermic) reactions where energy input is indispensable due to the conservation of energy. Ideally, such energy should be supplied by low temperature heat while plasma-generated reactive species promote initiation reactions. One promising approach is the use of vibrationally excited molecules which enhance the probability of chemisorption onto the catalyst surfaces. The role of vibrational species has been well investigated through molecular beam studies. However, the way to create such species has not been studied yet. Non-thermal plasma creates an oversaturated amount of vibrational species even at low temperature, showing great promises towards low temperature plasma catalysis of stable molecules. Furthermore, vibrational species uniquely create reaction pathways in homogeneous reactions via stepwise energy transfer gradually populating higher vibrational levels which eventually leads to the dissociation of stable molecules such as CO2. The special issue entitled “Plasma Conversion” consists of three review articles and 11 original research papers, focusing on the state-of-the-art plasma technology that is used for enhancing homogeneous/heterogeneous plasma catalytic conversion of greenhouse gases, nitrogen fixation and hydrocarbon chemistry. Review articles include the new catalyst synthesis approach using nonthermal plasma processes and the potential application of such unique catalysts is introduced (Rahimpour et al.) [1]. CH4 and CO2 reforming is one of the hot topics in plasma catalysis and research has been conducted mostly by experimental approaches. Bogaerts et al. discuss CH4 reforming and CO2 splitting and various mixtures from a modeling perspective, paying special attention to plasma chemistry and the role of plasma-generated vibrationally excited molecules [2]. Reactions involving vibrationally excited species need to be explored further and a numerical approach is truly beneficial providing insightful information towards the reaction mechanisms. Liquefaction of CH4 is to produce higher hydrocarbons via CH4 polymerization at ambient conditions (not for cryogenic methane condensation) [3]. Carbon containing liquid fuels such as gasoline and diesels produced via renewable electricity improve transportability and storage of renewable energy. Two research papers are related to heterogeneous plasma catalysis of CH4 and CO2 where nonthermal plasma is combined with Ni-supported reforming catalysts [4,5]. Research was conducted experimentally and plasma induced synergistic effects are highlighted. Van Rooij and Bongers discuss the homogeneous CO2 conversion with warm discharge, or low pressure microwave plasma [6,7]. Special emphasis on the vibrationally excited CO2 chemistry and CO2 dissociation by the latter mechanism is discussed. A novel heterogeneous plasma catalysis approach of CO2, where nonthermal plasma is combined with an oxygen permeating solid electrolyte membrane, is presented by Mori [8]. O2 is extracted directly from the plasma reaction field, and thus the CO2 conversion and energy efficiency were greatly improved. Moreover, CO2 microwave plasma diagnostics by optical emission spectroscopy [9], diagnostics plasma-catalyst interfacial phenomena [10], and atomistic simulations of plasma catalytic interactions [11] are included in the collection of this special issue. Three other papers focus on ammonia synthesis with atmospheric pressure plasma combined with heterogeneous catalysts [12–14]. Finally we would like to thank all contributors to this special issue and the editorial staff of Plasma Processes and Polymers for their great support. We hope that this issue contributes to exploring the new frontiers of plasma chemistry, and also to promoting the interdisciplinary interaction among the plasma science, chemical catalysis and surface science community, as well as other science specialists.

8-2-1 世界及び日本におけるCO2フリー水素の導入量の検討(8-2 エネルギー政策,Session 8 エネルギー評価・経済(エネ学含む))

8-2-1 世界及び日本におけるCO2フリー水素の導入量の検討(8-2 エネルギー政策,Session 8 エネルギー評価・経済(エネ学含む))

Significance of CO2-free hydrogen globally and for Japan using a long-term global energy system analysis

In this paper, the significance of CO2-free hydrogen is discussed using a long-term global energy system. The energy demand–supply system including CO2-free hydrogen was assumed, though there are still large uncertainties as to whether a global CO2-free hydrogen energy system will be deployed. System analysis was conducted using the global and long-term intertemporal optimization energy model GRAPE under severe CO2 emission constraints. Applied global CO2 constraints for 2050 were a 50% reduction from 1990 levels. CO2 constraints accounting for Intended Nationally Determined Contributions (INDCs) in each region were also considered. A variety of energy resources and technologies were considered in this model. Hydrogen can be produced from low-grade coal or natural gas with CO2 capture and electricity from renewable energy. The hydrogen CIF (cost, insurance, and freight) price for Japan was about 3.2 cents/MJ in 2030. Hydrogen demand technologies considered in this paper are hydrogen-fired power plants, direct combustion, combined heat and power (fuel cells, gas engines, and gas turbines), fuel cell vehicles, and hydrogen internal combustion engine vehicles. The majority of CO2-free hydrogen was deployed in the transportation sector. CO2-free hydrogen was utilized in the power sector, where deployment of other zero emission technology has some constraints. From an economic viewpoint, CO2-free hydrogen can reduce the global energy system cost. From the viewpoint of a localized region, such as Japan, deployment of CO2-free hydrogen can improve energy security and environmental indicators.

Evaluation of activated carbons based on olive stones as catalysts during hydrogen production by thermocatalytic decomposition of methane

Catalytic decomposition of methane over carbon materials has been intensively studied as an environmental approach for CO2-free hydrogen production without further by-products except hydrogen and valuable carbon. In this work, we will investigate the catalytic activity of activated carbons based on olive stones prepared by two different processes. Additionally, the effect of three major operational parameters: temperature, weight of catalyst and flow rate of methane, was determined. Therefore, a series of experiments were conducted in a horizontal-flow fixed bed reactor. The outflow gases were analysed using a mass spectrometer. The textural, structural and surface chemistry properties of both fresh and used activated carbons were determined respectively by N2 gas adsorption, X-Ray Diffraction and Raman and Temperature Programmed Desorption. The results reveal that methane decomposition rate increases with temperature and methane flow however it decreases with catalyst weight. The two carbon samples exhibit a high initial activity followed by a rapid decay. Textural characterization of the deactivated carbon presents a dramatic drop of surface area, pore and micropore volumes against an increase of average pore diameter confirming that methane decomposition occurs mainly in micropores. XRD characterization shows a turbostratic structure of fresh samples with more graphitization in deposed carbon explaining the lowest activity at the end of reaction. Raman spectra reveal the domination of the two bands G and D which varying intensities affirm that the different carbons tend to organise in aromatic rings. Finally the surface chemistry qualitatively changes greatly after methane dissociation for CAGOC unlike CAGOP but quantitatively a small difference is observed which indicates that these functionalities may have a role in this heterogeneous reaction but cannot be totally responsible. Among the two catalysts tested, CAGOC has the highest initial methane decomposition rate but CAGOP is the most stable one.

Characterizing Voltage Losses in an SO2 Depolarized Electrolyzer Using Sulfonated Polybenzimidazole Membranes

The hybrid sulfur cycle has been investigated as a means to produce CO2-free hydrogen efficiently on a large scale through the decomposition of H2SO4 to SO2, O2, and H2O, and then electrochemically oxidizing SO2 back to H2SO4 with the cogeneration of H2. The net effect is the production of hydrogen and oxygen from water. Recently, sulfonated polybenzimidazoles (s-PBI) have been investigated as a replacement for Nafion due to the ability to offer increased process efficiency through the generation of higher acid concentrations at lower potentials. Here, we measure the acid concentrations and individual potential contributions toward the overall operating voltage seen in the SO2-depolarized-electrolyzer. We then determine model parameters necessary to predict voltage losses in a cell over a wide range of operating temperatures, pressures, currents and reactant flow rates.

(Keynote) Japan's Policy and Activity on Hydrogen Energy

This presentation will provide an overview of Japan’s hydrogen and fuel cell activities, focusing on the latest policy, market and NEDO’s research, development and demonstration programs. In June 2014, Japanese Ministry of Economy, Trade and Industry (METI) compiled the “Strategic Road Map for Hydrogen and Fuel Cells” toward the realization of a “hydrogen society.” This road map states how Japan would be able to make use of hydrogen, what are goals to be achieved in each step of production, transportation, storage and utilization of hydrogen, and what kind of collaborative efforts could be possible among industry, academia and government for achieving these goals. Regarding market status, Japan has success to market introduction of hydrogen technology. Fuel cell micro combined heat and power system for household has been on market since 2009 and over 150,000 units are installed. Fuel cell vehicle was launched in December 2014 and around 70 hydrogen refueling stations have been operated now.The New Energy and Industrial Technology Development Organization (NEDO) has been conducting comprehensive technology development and demonstrative research programs on hydrogen energy. The most recent result from NEDO’s program such as new materials for PEFC, analysis technology of morphology, electrochemical reaction and mass transfer in MEA, evaluation technology for long time fuel cell durability will be addressed. Following current topic, NEDO’s future challenge to develop hydrogen energy demand will be presented. NEDO just started R&D program to develop large scale n hydrogen supply chain with long-distance transportation of hydrogen and hydrogen gas turbine technology. NEDO is now also conducting Power to Gas which is a key technology to provide CO2 free hydrogen in the future.

HAZID for CO2-Free Hydrogen Supply Chain FEED (Front End Engineering Design)

We at Kawasaki have proposed a “CO2 free H2 chain” using the abundant brown coal of Australia as a hydrogen source. We developed the basic design package and finished the Front End Engineering Design (FEED) in 2014. There are not only the hazards of the processing plant system, but also the characteristic hazards of a hydrogen plant system. We considered and carried out Hazard Identification (HAZID) as the most appropriate approach for safety design in this stage. This paper describes the safety design and HAZID which we practiced for the CO2-Free Hydrogen Supply Chain FEED.

Development of methane decarbonisation based on liquid metal technology for CO2-free production of hydrogen

The development of a low-carbon technique to produce hydrogen from fossils would be of great importance during the transition to a long-term sustainable energy system. Methane decarbonisation, the well-known transformation of methane into hydrogen and solid carbon, is a potential candidate in this regard. At the Institute for Advanced Sustainability Studies (IASS), a new alternative technology for methane decarbonisation applying liquid metal technology was proposed and an ambitious programme was set up in collaboration with the Karlsruhe Institute of Technology (KIT). The comprehensive programme included the following: conceptual design of a liquid metal bubble column reactor and material testing, process engineering incorporating carbon separation and hydrogen purification, and a socio-economic analysis. In the present paper, an overview of the programme along with some of the results, are presented. Results from the experimental campaigns show that the liquid metal reactor design works effectively in producing hydrogen and carbon separation. Other aspects of the technology such as socio-economics, environmental impact, and scalability also seem to be favourable making methane decarbonisation based on liquid metal technology a potential candidate for CO2-free hydrogen production.

Pathways to ultra-low platinum group metal catalyst loading in proton exchange membrane electrolyzers

Hydrogen is one of the world's most important chemicals, with global production of about 50billion kg/year. Currently, hydrogen is mainly produced from fossil fuels such as natural gas and coal, producing CO2. Water electrolysis is a promising technology for fossil-free, CO2-free hydrogen production. Proton exchange membrane (PEM)-based water electrolysis also eliminates the need for caustic electrolyte, and has been proven at megawatt scale. However, a major cost driver is the electrode, specifically the cost of electrocatalysts used to improve the reaction efficiency, which are applied at high loadings (>3mg/cm2 total platinum group metal (PGM) content). Core–shell catalysts have shown improved activity for hydrogen production, enabling reduced catalyst loadings, while reactive spray deposition techniques (RSDT) have been demonstrated to enable manufacture of catalyst layers more uniformly and with higher repeatability than existing techniques. Core–shell catalysts have also been fabricated with RSDT for fuel cell electrodes with good performance. Manufacturing and materials need to go hand in hand in order to successfully fabricate electrodes with ultra-low catalyst loadings (<0.5mg/cm2 total PGM content) without significant variation in performance. This paper describes the potential for these two technologies to work together to enable low cost PEM electrolysis systems.

Catalytic membrane reactors for SO3 decomposition in Iodine–Sulfur thermochemical cycle: A simulation study

The possibility of applying a catalytic membrane reactor (CMR) to SO3 decomposition in a low-temperature range was theoretically evaluated with the purpose of producing CO2-free hydrogen in an Iodine–Sulfur thermochemical cycle. A one-dimensional, isothermal and plug-flow model was developed for a cocurrent membrane reactor with selective permeation from the reactant stream to the permeate stream. Simulation results have revealed that CMRs can greatly reduce the reaction temperature for SO3 decomposition from the conventional 1200–1400 K to about 900 K. We predicted that porous inorganic membranes with a high O2 permeability and with selectivities of more than 50 for O2/SO3 and less than 10 for O2/SO2 had the potential to effectively improve SO3 conversion. CMRs were simulated to carry out SO3 decomposition at different catalyst weights, reaction temperatures, and SO3 feed flow rates as well as pressures in feed and permeate streams. SO3 conversion at 900 K was increased to 0.93 beyond the equilibrium conversion of 0.28 due to a shift in thermodynamic equilibrium.