Sabatier Reaction Research Articles

Thermal Management Approach to Stabilization of Disordered Active Sites for Sabatier Reaction.

The transition metal nanocatalysts containing disordered active sites can potentially achieve efficient Sabatier reactions with high selectivity. However, it remains a challenge to maintain the stability of these active sites in such an exothermic reaction. Here, a thermal management approach is reported to address this challenge. Specifically, an efficient and stable catalytic system is developed by integrating urchin-like Ru nanoparticles with disordered active sites (d-RuNUs) and multi-walled carbon nanotubes (MWCNTs) as heat transfer framework, which achieves a CH4 yield of 3.3mol g-1 h-1 with nearly 100% selectivity in 12h. The characterizations reveal that the thermal-induced crystallization seriously weakens the adsorption of CO2, leading to significant degradation of catalytic performance. The heat transfer simulation confirms that the MWCNTs with high thermal conductivity play a key role in rapidly redistributing the reaction heat, thereby preventing the crystallization of disordered structures. This work elucidates the deactivation mechanism of disordered active sites in exothermic reactions and opens the avenue for local thermal management of non-thermal equilibrium reactions.

Direct CO2 hydrogenation over Na and CeO2-promoted Iron and Cobalt-based Catalysts Supported on MCM-41

This contribution has studied iron or cobalt-based Fischer-Tropsch catalysts, promoted with CeO2 and Na and supported on MCM-41 mesoporous silica in the direct CO2 hydrogenation to hydrocarbons. The cobalt-based catalyst is more active in the presence of ceria as a promoter, presenting long-chain hydrocarbons under reaction conditions of 350 °C, 40 bar, H2/CO2 = 3, and GHSV = 6000 mL g-1 h-1. The characterization of the catalysts suggests that CoCeNa/M exhibits a strong Co-O-Si bond formation, preventing the cobalt oxide reduction to Co2+ species, which can be associated with methane production. On the other hand, iron-based catalysts present higher CO and CH4 concentrations, as shown via in situ DRIFTS, suggesting a possible iron carbide phase, which can be formed by the severe FTS reaction conditions, producing a high concentration of water and competing with Sabatier reaction.

Solar‐Assisted CO2 Methanation via Photocatalytic Sabatier Reaction by Calcined Titanium‐based Organic Framework Supported RuOx Nanoparticles

AbstractCO2 reduction by sunlight under mild reaction conditions is a research area of increasing interest expected to favor decarbonization and produce fuels and chemicals in the circular economy. We hereby report on the development of a series of titanium oxide‐based solids produced by calcination of MIL‐125(Ti)‐NH2 decorated with RuOx nanoparticles (1 wt %) material at temperatures from 350 to 650 °C and used as photocatalysts for CO2 methanation under simulated sunlight irradiation (45 mW/cm2) at <200 °C and 1.5 atm total pressure. The material synthesized at 350 °C produced the highest photoactivity of the series (4.73 mmol g−1 CH4 at 22 h and an apparent quantum yield at 400, 500 and 750 nm of 0.76, 0.65 and 0.54 %, respectively), comparing favorably with the activities of other MOF‐based materials reported so far. Insights into the material's photocatalytic performance and a study of the possible reaction pathways during CO2 methanation were obtained by electrochemical impedance, electron spin resonance, photoluminescence and in situ FT‐IR spectroscopies together with transient photocurrent and hydrogen temperature programed desorption measurements. The study showed the possibility of using MOF‐based materials as precursors to develop metal oxide photocatalysts with enhanced activities for solar‐driven gaseous CO2 photomethanation.

DEVELOPMENT OF AN ENERGY-SAVING TECHNOLOGY FOR THE PRODUCTION OF SYNTHETIC METHANE FROM CARBON DIOXIDE. 1. RESEARCH OF KINETICS AND MACRO-KINETICS OF THE SABATIER REACTION ON MODIFICATIONS OF THE SERIAL NI/Α-AL2O3 CATALYST GIAP-3-6N

This study presents the results of laboratory research of kinetics and mechanisms of heterogeneous catalytic reactions of hydrogenation of carbon dioxide to carbon monoxide and methane through the Sabatier reaction on modifications of the serial Ni/α-Al2O3 catalyst GIAP-3-6N manufactured in Ukraine. The research was carried out on a laboratory bench using a classic glass gradientless reactor with internal piston stirring, which provides kinetic equations at the level of physicochemical constants of the reactions under consideration. A detailed analysis and review of the literature in the areas of kinetic research of our interest was carried out. A detailed comparison of the kinetic parameters obtained by us for the powder (kinetic) form of contact with a nickel content of 7.5 % (NiO = 7.5 %) with a similar and one of the best foreign analogs containing nickel, Katalco 57-4 (NiO = 15−18 %), produced by the British chemical and metallurgical company Johnson Matthey, was performed. The results of the research confirmed almost equal parameters of the kinetic activity of the compared catalysts in the reactions of hydrogenation of carbon dioxide with hydrogen, including the «Sabatier» reaction, which made it possible to propose a similar mechanism of the processes, calculate the reaction rate constants and their activation energy, propose (determine) kinetic equations for design of reactors and processes, both with the loading of a domestic catalyst and its replacement with a foreign analog. Kinetic equations will be used in the development of multi-ton synthesis gas plants for the production of methanol, ammonia, and synthetic methane, as well as carbon-free e-fuel for internal combustion engines that meet modern climate requirements. Bibl. 28, Fig. 4, Tab. 6.

Low Temperature Sabatier CO2 Methanation

AbstractThe CO2 methanation reaction, or Sabatier reaction, is experiencing renewed interest in the context of large‐scale recycling of point CO2 emissions, leading to the power‐to‐gas technology. The reaction represents a flexible route to transform CO2 into methane by hydrogenation with (green) dihydrogen. This exothermic transformation takes place at a reasonable rate at temperatures above 200 °C and is directed to the targeted product at low temperatures. The CO2 methanation nevertheless remains kinetically limited due to the chemical stability of CO2 and the high bond dissociation energy for C═O in CO2. Therefore, the current urgent demand is for the development of catalysts and associated processes with superior activity for CO2 activation at low temperatures. This critical review aims to overview the state of the art of this low‐temperature technology using thermal, plasma and photo‐assisted catalysis. We summarize research advances around low‐temperature CO2 methanation, focusing on catalyst formulations (metal, supports and promoters), reaction mechanisms and suitable activation processes. We discuss each of these critical aspects of the technology and identify the main challenges and opportunities for low temperature (≤200 °C) CO2 methanation.

Using MCFC for capturing CO2 from flue gases and delivering to Sabatier reactor for SNG synthesis

In contemporary power generation, enhancing efficiency and mitigating environmental contamination are of paramount importance. The imperative to curtail greenhouse gas emissions stands as a preeminent challenge within this sector. Concurrently, there is a marked surge in the exploitation of renewable energy sources, which, due to their intermittent nature, precipitates the imperative for advanced energy storage solutions. This paper introduces an integrated system designed to address both the reduction of CO2 emissions and the storage of energy. The advocated system integrates a Molten Carbonate Fuel Cell (MCFC), Solid Oxide Electrolysis Cell (SOEC), and a Sabatier reactor. The MCFC is employed for its proficient CO2 capture capabilities at the cathode, exhibiting remarkable efficiency, operational flexibility, and a high CO2 separation quotient. The SOEC is recognized for its effective hydrogen production, leveraging high operational temperatures to augment hydrogen output while diminishing electrical energy consumption through thermal energy substitution. The Sabatier reactor is utilized for catalytic methanation, transforming CO2 into Substitute Natural Gas—a compound predominantly comprising methane and hydrogen with minimal CO2 and water traces. This system facilitates the capture and utilization of over 80% of CO2 from exhaust fumes, achieving an overall energy efficiency of 71%. The system's design and off-design operational parameters were meticulously modeled and analyzed.

Optically selective catalyst design with minimized thermal emission for facilitating photothermal catalysis

Converting solar energy into fuels is pursued as an attractive route to reduce dependence on fossil fuel. In this context, photothermal catalysis is a very promising approach through converting photons into heat to drive catalytic reactions. There are mainly three key factors that govern the photothermal catalysis performance: maximized solar absorption, minimized thermal emission and excellent catalytic property of catalyst. However, the previous research has focused on improving solar absorption and catalytic performance of catalyst, largely neglected the optimization of thermal emission. Here, we demonstrate an optically selective catalyst based Ti3C2Tx Janus design, that enables minimized thermal emission, maximized solar absorption and good catalytic activity simultaneously, thereby achieving excellent photothermal catalytic performance. When applied to Sabatier reaction and reverse water-gas shift (RWGS) as demonstrations, we obtain an approximately 300% increase in catalytic yield through reducing the thermal emission of catalyst by ~70% under the same irradiation intensity. It is worth noting that the CO2 methanation yield reaches 3317.2 mmol gRu−1 h−1 at light power of 2 W cm−2, setting a performance record among catalysts without active supports. We expect that this design opens up a new pathway for the development of high-performance photothermal catalysts.

Comparing CO2 Storage and Utilization: Enhancing Sustainability through Renewable Energy Integration

Addressing the environmental challenges posed by CO2 emissions is crucial for mitigating global warming and achieving net-zero emissions by 2050. This study compares CO2 storage (CCS) and utilization (CCU) technologies, highlighting the benefits of integrating captured CO2 into fuel production. This paper focuses on various carbon utilization routes such as Power-to-Gas via the Sabatier reaction, indirect production of DME, and Power-to-Fuel technologies. The maturity of these technologies is evaluated using the Technology Readiness Level (TRL) method, identifying the advancements needed for future implementation. Additionally, global regulations and policies surrounding carbon capture and storage are reviewed to provide context for their current status. The study emphasizes the potential of CCU technologies to reduce future CO2 emissions by converting captured CO2 into valuable fuels and chemicals, thus supporting the transition to a sustainable energy system. The findings indicate that while CCS technologies are more mature, promising CCU technologies can significantly contribute to reducing greenhouse gas emissions if green hydrogen becomes more affordable. This research underscores the importance of further technological development and economic evaluation to enhance the feasibility and adoption of CCU technologies in the pursuit of long-term environmental sustainability.

CO2 Hydrogenation on Carbides Formed in situ on Carbon-Supported Iron-Based Catalysts in High-Density Supercritical Medium.

CO2 conversion via hydrogenation on iron-based catalysts on non-carbon supports produces mainly CO or methane by the Sabatier reaction, while the formation of C2+ hydrocarbons is of greatest interest. CxHy production from CO2 may be considered as a two-step process with the initial formation of carbon monoxide by the reverse water gas shift reaction followed by the Fischer-Tropsch synthesis (FTS). In the present work CO2 hydrogenation over iron-based catalysts (Fe, FeCr, FeK) deposited on a carbon carrier has been studied. The catalyst structure has been investigated by XRD, TEM, XPS, Mössbauer spectroscopy and in situ magnetometry. Spinel-type oxide phases (magnetite Fe3O4; maggemite γ-Fe2O3, and, in the case of FeCr/C catalyst, iron chromite Fe1+xCr2-xO4) are formed on the catalysts, and they contribute exclusively to the CO production. Iron carbides, active in FTS, are formed on Fe- and FeK-catalysts during pre-activation in reducing environment and then during the reaction. The reaction over the 20Fe1K/C catalyst in supercritical high-density CO2/H2 substrate (400°C, 8.5 MPa) leads to 72% selectivity for C1-C12+ hydrocarbons (alkanes and alkenes). Under the same conditions, iron carbides do not form on the FeCr/C catalysts, and CO2 hydrogenation results in the CO formation with the selectivity of 90-100%.

Direct Catalytic Conversion of Carbon Dioxide to Liquid Hydrocarbons over Cobalt Catalyst Supported on Lanthanum(III) Ion‐Doped Cerium(IV) Oxide

AbstractDirect CO2 conversion to liquid hydrocarbons (HCs) in a single process was achieved using cobalt (Co) catalysts supported on lanthanum ion (La3+)‐doped cerium oxide (CeO2) under a gas stream of H2/CO2/N2=3/1/1. The yield of liquid HCs was the highest for 30 mol% of La3+‐doped CeO2, which was because extrinsic oxygen vacancy formed by doping La3+ could act as an effective reaction site for reverse water gas shift reaction. However, the excess La3+ addition afforded surface covering lanthanum carbonates, resulting in depression of the catalytic performance. On the other hand, bare CeO2 lead to an increase in the selectivity of undesirable methane, which arose from reduction of CO2 to CO proceeding by intrinsic oxygen vacancy generated by only Ce3+, and weaker CO2 capture ability of intrinsic oxygen vacancy than extrinsic one, resulting in the proceeding of Sabatier reaction on Co catalyst. The rational design of reaction sites presented in this study will contribute to sustainability.

CO2 methanation under more realistic conditions: Influence of O2 and H2O on Ni-based catalysts’ performance

In this work, Ni-based catalysts (15 wt%) promoted with Y (15 wt%) and Fe (1 wt%) supported on an optimized USY zeolite were prepared by incipient wetness co-impregnation, characterized by XRD, TGA, N2 adsorption, H2-TPR, and TEM, and finally tested towards CO2 methanation (total flow of 274 mL/min, H2/CO2 = 4, 2.5 bar and 0.2 g of catalyst) including water or oxygen in the feed. On one side, water (∼5 vol%) shows a limited impact on catalysts’ performance despite being a product of the CO2 methanation reaction. These results were mainly attributed to the high hydrophobicity of the studied catalysts, as well as to the absence of additional/competitive reactions. On the other side, oxygen (∼4 vol%) negatively affected the activity of the tested catalysts, decreasing the CO2 conversion, particularly for the unpromoted catalysts. Two different aspects were found to be responsible for the decline in activity: on the one hand, the H2/O2 reaction, which is faster than the CO2 methanation and decreases H2 availability for Sabatier reaction; on the other hand, the partial re-oxidation of nickel active sites, evidenced by post-test characterization, which decreases the number of Ni0 active sites, and therefore, leads to a drop in CO2 conversion. Reversibility tests to assess O2 effect were also performed, indicating that its impact on the catalytic performances mainly arises from the decrease in H2 partial pressure, leading to operation under sub-stoichiometric CO2 methanation conditions (H2/CO2 ∼ 3). When compared to a commercial Al2O3–supported Ni catalyst, zeolite-based samples demonstrated superior resistance to H2O and O2.

Metal-oxide nanocomposites by low temperature exsolution from perovskite-like La nickelates: Synthesis, morphology, and catalytic properties in CO2 hydrogenation

Thermal decomposition of the citrate-gel precursors with La/Ni = 1/1 and La/Ni = 3/2 results in the formation at T ≥ 700 °C the single phase perovskite LaNiO3 and the disordered perovskite-like phase La3Ni2O6+x. A reduction of both compounds during thermal processing in a 5 % H2/Ar gas mixture proceeds in two definite steps. The first stage of LaNiO3 reduction at 250 - 350 °C results in the formation of an O-deficient La2Ni2O5 compound. A similar process during the reduction of La3Ni2O6+x occurs at 300–400 °C with the lack of significant changes in the XRD pattern. An unusual feature of these processes deals with the formation of Ni0 nanoparticles on the surface of both reduction intermediates at 350–400 °C while similar processes are usually observed during redox exsolution of metals from several complex oxides at T > 700 °C only. As-obtained Ni/LaxNiOy nanocomposites demonstrated significant catalytic activity and excellent selectivity and stability in the Sabatier reaction.

Adjacent Reaction Sites of Atomic Mn2O3 and Oxygen Vacancies Facilitate CO2 Activation for Enhanced CH4 Production on TiO2-Supported Nickel-Hydroxide Nanoparticles

The catalytic conversion of carbon dioxide (CO2) to methane (CH4) through the “Sabatier reaction”, also known as CO2 methanation, presents a promising avenue for establishing a closed carbon loop. However, the competitive reverse water gas shift (RWGS) reaction severely limits CH4 production at lower temperatures; therefore, developing highly efficient and selective catalysts for CO2 methanation is imperative. In this regard, we have developed a novel nanocatalyst comprising atomic scale Mn2O3 species decorated in the defect sites of TiO2-supported Ni-hydroxide nanoparticles with abundant oxygen vacancies (hereafter denoted as NiMn-1). The as-prepared NiMn-1 catalyst initiates the CO2 methanation at a temperature of 523 K and delivers an optimal CH4 production yield of 21,312 mmol g−1 h−1 with a CH4 selectivity as high as ~92% at 573 K, which is 45% higher as compared to its monometallic counterpart Ni-TiO2 (14,741 mmol g−1 h−1). Physical investigations combined with gas chromatography analysis corroborate that the exceptional activity and selectivity of the NiMn-1 catalyst stem from the synergistic cooperation between adjacent active sites on its surface. Specifically, the high density of oxygen vacancies in Ni-hydroxide and adjacent Mn2O3 domains facilitate CO2 activation, while the metallic Ni domains trigger H2 splitting. We envision that the obtained results pave the way for the design of highly active and selective catalysts for CO2 methanation.

Auto‐Pressurized Multi‐Stage Tesla‐Valve Type Microreactors in Carbon Monoliths Obtained Through 3D Printing: Impact of Design on Fluid Dynamics and Catalytic Activity

AbstractThe present research exploits an innovative methodology for producing auto‐pressurized carbon microreactors with a precise and controlled structure analyzing the influence of their design on the fluid dynamics and their catalytic performance. Carbon monoliths with Tesla‐valve shape channels (Tesla, T, and modified Tesla, Tm) are synthesized through the combination of 3D printing and sol–gel process and further probed as Ni/CeO2 supports on CO2 methanation. The experimental results and mathematical modeling corroborated the improved performance obtained through the complex design compared to a conventional one. In addition to chaotic fluid flow induced by the deviation in flow direction, which improves the reagents‐active phase interaction, local pressure increases due to convergence of flows may enhance the Sabatier reaction according to Le Châtelier's principle. Conversely to straight channels, T and Tm are not affected by flow rate and presented chemical control. Tesla‐valve with curved angle (Tm) improved the mass transfer, achieving higher conversion and ≈30% reaction rate increase regarding right angle (T). Thus, this auto‐pressurized multi‐stage Tesla‐valve monolith opens the gate to design specific and advanced functional materials for multitude chemical reactions where not only the reactant‐active phase contact can be maximized but also the reaction conditions can be controlled to maximize the reaction kinetics.

Selectivity control between reverse water-gas shift and fischer-tropsch synthesis in carbon-supported iron-based catalysts for CO2 hydrogenation

CO2 hydrogenation to chemicals and fuels has the potential to alleviate CO2 emissions and displace fossil resources simultaneously via consecutive RWGS and FTS reactions, also known as CO2-FTS. As Fe-based catalysts are active and selective for both reactions, their bifunctionality requires a delicate balance between the RWGS and FTS. In this work, we investigated the thermodynamic constraints of RWGS and CO2-FTS, the influence of CO2 conversion on selectivity and the influence of Fe nanoparticle size within the range of 4.7 to 10.3 nm. An inert carbon support was selected to rule out metal-support interaction and promoting effects of the support. Catalytic performance was evaluated at 300 °C, 11 bar, H2/CO2/Ar = 3/1/1, 600 to 72000 mL·gcat-1·h-1. At a CO2 conversion level below RWGS equilibrium conversion of 23 %, RWGS was found to be the primary and dominant reaction. No primary Sabatier reaction was observed. At higher CO2 conversion till the CO2-FTS threshold of 42 %, the secondary FTS reaction became dominant. Notably, a non-linear relation between CO2 conversion and CO selectivity was discovered. Comparing two catalysts with identical 5 wt% Fe loading but different average Fe nanoparticle size (6.6 and 8.4 nm), the 8.4 nm Fe catalyst was at least two times more active than the 6.6 nm Fe catalyst. In situ Mössbauer spectroscopy suggested a positive correlation between particle size, carburization and selectivity towards long-chain hydrocarbons. For these potassium-promoted carbon-supported Fe-based catalysts, nanoparticles of at least 8 nm are required for the formation of Fe carbides and improved reactivity.

Economy of scale for green hydrogen-derived fuel production in Nepal.

Opportunity for future green hydrogen development in Nepal comes with end-use infrastructural challenges. The heavy reliance of industries on fossil fuels (63.4%) despite the abundance of hydroelectricity poses an additional challenge to the green transition of Nepal. The presented work aims to study the possibility of storing and utilizing spilled hydroelectricity due to runoff rivers as a compatible alternative to imported petroleum fuels. This is achieved by converting green hydrogen from water electrolysis and carbon dioxide from carbon capture of hard-to-abate industries into synthetic methane for heating applications via the Sabatier process. An economy-of-scale study was conducted to identify the optimal scale for the reference case (Industries in Makwanpur District Nepal) for establishing the Synthetic Natural Gas (SNG) production industry. The techno-economic assessment was carried out for pilot scale and reference scale production unit individually. Uncertainty and sensitivity analyses were performed to study the project profitability and the sensitivity of the parameters influencing the feasibility of the production plant. The reference scale for the production of Synthetic Natural Gas was determined to be 40 Tons Per Day (TPD), with a total capital investment of around 72.15 Million USD. Electricity was identified as the most sensitive parameter affecting the levelized cost of production (LCOP). The 40 TPD plant was found to be price competitive to LPG when electricity price is subsidized below 3.55 NPR/unit (2.7c/unit) from 12 NPR/unit (9.2c/unit). In the case of the 2 TPD plant, for it to be profitable, the price of electricity must be subsidized to well below 2 NPR/kWh. The study concludes that the possibility of SNG production in Nepal is profitable and price-competitive at large scales and at the same time limited by the low round efficiency due to conversion losses. Additionally, it was observed that highly favorable conditions driven by government policies would be required for the pilot-scale SNG project to be feasible.

Biogas upgrading by intensified methanation (SESaR): Reaction plus water adsorption - desorption cycles with Ni-Fe/Al2O3 catalyst and LTA 5A zeolite

This work is conducted within the framework of the Power to Gas (PtG) technologies, focusing on the topic of “biogas upgrading”. The objective is to enhance the CH4 content of biogas streams by utilizing the CO2 present in these streams through the Sabatier reaction, thereby producing a renewable alternative to natural (fossil) gas. Referred to as “SESaR”(Sorption Enhanced Sabatier Reaction), this process employs a catalytic fixed-bed reactor, featuring selective water adsorption using LTA 5A zeolites, as an innovative approach to traditional methanation reactors. The catalyst used comprises Ni-Fe (7.5:2.5 wt/wt) as the active metallic phase supported on γ-Al2O3. Experimental work has been divided in two sets of trials. The first set focuses on the hydrogenation of CO2 as single reactant (H2 also supplied in the inlet with 4:1 = H2:CO2 molar ratio). The second set of experiments was carried out with a synthetic gas mixture representative of a sweetened biogas stream (molar ratio CH4:CO2 = 7:3). Maximum intensification behavior for CO2 conversion was found at 350 °C, also showing that CH4 presence in the inlet gas has negligible influence on the conversion of CO2. Selectivity to CO is minimized at temperatures exceeding 300 °C and remains constant after three consecutive cycles of methanation, water adsorption, and desorption. The Fe-Ni catalyst has demonstrated sustained performance throughout the experimental cycles, exhibiting no significant loss of activity.

Performance of Ni/Si‐MCM‐41 catalysts in CO2 methanation

AbstractThe production of methane from the methanation reaction between H2 and CO2, also known as the Sabatier reaction, is one way to diversify the global energy matrix, providing a use for CO2. This work evaluates the performance in this reaction of Ni catalysts supported on type MCM‐41 silica, synthesized y a wet impregnation method. Catalytic tests were performed for 2.5 h under atmospheric pressure. The reaction variables considered were the catalyst nickel mass content (5% and 10%), temperature (T = 400 and 550°C), reactant ratio (H2/CO2 = 4 and 2.5), and space velocity (VHSV = 5 and 10 L g−1 h−1). The catalysts were characterized by Brunauer–Emmett–Teller (BET), X‐ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x‐ray spectroscopy (EDS) analyses before the reactions, and by thermogravimetric analysis (TGA), SEM, and EDS analyses after the reactions. The reaction variables were evaluated using an experimental design with 2 factors and 4 variables, in order to determine the effects of the reaction conditions on catalyst selectivity, reactant conversion, and reaction yields in terms of CH4 and CO. The best result was obtained using a reactant ratio of 2.5, space velocity of 5 L g−1 h−1, and reaction temperature of 550°C, resulting in 93.7% selectivity for methane, 69.4% CO2 conversion, 74% H2 conversion, and methane yield of 20.69%. Findings show Ni/Si‐MCM‐41 catalyst's applicability in methanation, advancing CH4 production technology, and addressing local demand while reducing CO2 emissions.

Design of a novel wastewater reuse system for space station based on urea electrooxidation technology

The replenishment of water resources in a space station is essential for achieving an astronaut's long-term and on-orbit residence. Recycling his or her urine is one of important and major ways of wastewater recovery. However, traditional urine treatment methods have the disadvantages of equipment that takes large space, complex procedures and low atomic utilization. Therefore, this paper designs a novel wastewater reuse system that treats urine based on urea electrooxidation technology, introduces methane fuel cell coupled with the Sabatier reactor and hydrogen-oxygen fuel cell to further utilize urine treatment products and to allocate water resources precisely in the space station through designing grading treatment and dynamic control systems. The wastewater reuse system designed in the paper contributes to saving valuable space and reducing energy consumption during urine treatment, thus improving water recovery rate and optimizing resource allocation.

Ni/CeZr deposition on metallic mesh supports for CO2 methanation. Adherence and morphology

Structured supports suitable for highly demanding reactions in heat and mass transfer such as the Sabatier reaction were synthesised. The use of a metallic mesh as the support is promising. In this work, a treatment strategy for the metallic substrate and deposition of the support and the catalytic phase was proposed to obtain a thin, homogeneous, and crack-free layer that avoid the attack of the metallic substrate under the reaction conditions. The metallic surface of the meshes was thermally pre-treated under different conditions to generate roughness. A layer of Ce and Zr oxides was deposited from Nyacol® to generate the catalyst support that act, at the same time, as a barrier between the reaction atmosphere and the surface of the meshes. Subsequently, nickel was deposited as an active phase by impregnation. The elimination of the excess was studied by air blowing and centrifugation. The morphology, phase structure and adhesion of the layer were investigated by SEM, EDX and adherence test. The results showed that the load and the adhesion of the layer were affected by the mesh size and the conditions of the excess removal as well as the concentration of the slurry. The adhesion of the active phase was excellent under severe conditions.