@misc{GonzalezCastanoNavarrodeMiguelBoelteetal., author = {Gonzalez-Castano, Miriam and Navarro de Miguel, Juan Carlos and Boelte, Jens-H. and Centeno, Miguel Angel and Klepel, Olaf and Arellano-Garcia, Harvey}, title = {Assessing the impact of textural properties in Ni-Fe catalysts for CO2 methanation performance}, series = {Microporous and Mesoporous Materials}, volume = {327}, journal = {Microporous and Mesoporous Materials}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2021.111405}, pages = {7}, abstract = {In heterogeneous catalysis, the benefits of employing adequate textural properties on the catalytic performances are usually stated. Nevertheless, the quantification of the extent of improvement is not an easy task since variations on the catalysts' specific areas and pore structures might involve modifications on a number of other surface catalytic features. This study establishes the impact of the catalyst textural properties on the CO2 methanation performance by investigating bimetallic Ni-Fe catalysts supported over carbon supports with different textural properties regarding surface area and pore structure. The comparable metal loading and dispersions attained for all systems enabled establishing forthright relationships between the catalyst textural properties and CO2 methanation rate. Once the influence of the external mass diffusions on the catalysts' performance was experimentally discarded, the estimated Thiele modulus and internal effectiveness (φ and ηEff) values showed that the catalyst performance was majorly governed by the surface reaction rate whilst the pore size affected in no significant manner within the examined range (Dpore = 10.2 to 5.8 nm). Therefore, the rapport between the catalyst performance and surface area was quantified for the CO2 methanation reaction over Ni-Fe catalysts: increasing the surface area from 572 to 802 m2/g permit obtaining ca. 10\% higher CO2 conversions.}, language = {en} } @misc{GonzalezCastanoNavarrodeMiguelPernkovaetal., author = {Gonz{\´a}lez-Casta{\~n}o, Miriam and Navarro de Miguel, Juan Carlos and Pernkova, A. and Centeno, Miguel Angel and Odriozola, Jos{\´e} Antonio and Arellano-Garcia, Harvey}, title = {Ni/YMnO3 perovskite catalyst for CO2 methanation}, series = {Applied Materials Today}, volume = {23}, journal = {Applied Materials Today}, doi = {10.1016/j.apmt.2021.101055}, abstract = {Ni/YMnO3 perovskite catalyst for CO2 methanation}, language = {en} } @misc{GonzalezCastanoMoralesNavarrodeMigueletal., author = {Gonzalez-Cast{\~a}no, Miriam and Morales, Carlos and Navarro de Miguel, Juan Carlos and Boelte, Jens H. and Klepel, Olaf and Flege, Jan Ingo and Arellano-Garc{\´i}a, Harvey}, title = {Are Ni/ and Ni5Fe1/biochar catalysts suitable for synthetic natural gas production? A comparison with γ-Al2O3 supported catalysts}, series = {Green Energy \& Environment}, volume = {8}, journal = {Green Energy \& Environment}, number = {3}, issn = {2468-0257}, doi = {10.1016/j.gee.2021.05.007}, pages = {744 -- 756}, abstract = {Among challenges implicit in the transition to the post-fossil fuel energetic model, the finite amount of resources available for the technological implementation of CO2 revalorizing processes arises as a central issue. The development of fully renewable catalytic systems with easier metal recovery strategies would promote the viability and sustainability of synthetic natural gas production circular routes. Taking Ni and NiFe catalysts supported over γ-Al2O3 oxide as reference materials, this work evaluates the potentiality of Ni and NiFe supported biochar catalysts for CO2 methanation. The development of competitive biochar catalysts was found dependent on the creation of basic sites on the catalyst surface. Displaying lower Turn Over Frequencies than Ni/Al catalyst, the absence of basic sites achieved over Ni/C catalyst was related to the depleted catalyst performances. For NiFe catalysts, analogous Ni5Fe1 alloys were constituted over both alumina and biochar supports. The highest specific activity of the catalyst series, exhibited by the NiFe/C catalyst, was related to the development of surface basic sites along with weaker NiFe-C interactions, which resulted in increased Ni0:NiO surface populations under reaction conditions. In summary, the present work establishes biochar supports as a competitive material to consider within the future low-carbon energetic panorama.}, language = {en} } @misc{GonzalezCastanoNavarrodeMiguelSinhaetal., author = {Gonz{\´a}lez-Casta{\~n}o, Miriam and Navarro de Miguel, Juan Carlos and Sinha, F. and Ghomsi Wabo, Samuel and Klepel, Olaf and Arellano-Garcia, Harvey}, title = {Cu supported Fe-SiO2 nanocomposites for reverse water gas shift reaction}, series = {Journal of CO2 Utilization}, volume = {46}, journal = {Journal of CO2 Utilization}, issn = {2212-9820}, doi = {10.1016/j.jcou.2021.101493}, pages = {8}, abstract = {This work analyses the catalytic activity displayed by Cu/SiO2, Cu-Fe/SiO2 and Cu/FSN (Fe-SiO2 nanocomposite) catalysts for the Reverse Water Gas Shift reaction. Compared to Cu/SiO2 catalyst, the presence of Fe resulted on higher CO's selectivity and boosted resistances against the constitution of the deactivation carbonaceous species. Regarding the catalytic performance however, the extent of improvement attained through incorporation Fe species strongly relied on the catalysts' configuration. At 30 L/gh and H2:CO2 ratios = 3, the performance of the catalysts' series increased according to the sequence: Cu/SiO2 < Cu-Fe/SiO2 << Cu/FSN. The remarkable catalytic enhancements provided by Fe-SiO2 nanocomposites under different RWGS reaction atmospheres were associated to enhanced catalyst surface basicity's and stronger Cu-support interactions. The catalytic promotion achieved by Fe-SiO2 nanocomposites argue an optimistic prospective for nanocomposite catalysts within future CO2-valorising technologies.}, language = {en} } @misc{BaenaMorenoGonzalezCastanoNavarrodeMigueletal., author = {Baena-Moreno, Francisco Manuel and Gonz{\´a}lez-Casta{\~n}o, Miriam and Navarro de Miguel, Juan Carlos and Miah, Kamal Uddin Mohammad and Ossenbrink, Ralf and Odriozola, Jos{\´e} Antonio and Arellano-Garcia, Harvey}, title = {Stepping toward Efficient Microreactors for CO2 Methanation: 3D Printed Gyroid Geometry}, series = {ACS Sustainable Chemistry \& Engineering}, volume = {9}, journal = {ACS Sustainable Chemistry \& Engineering}, number = {24}, issn = {2168-0485}, doi = {10.1021/acssuschemeng.1c01980}, pages = {8198 -- 8206}, abstract = {This work presents a comparative study towards the development of efficient micro-reactors based on 3D-printed structures. Thus, the study evaluates the influence of the metal substrate geometry on the performance of structured catalysts for the CO2 methanation reaction. For this purpose, 0.5\%Ru-15\%Ni/MgAl2O4 catalyst is wash coated over two different micro-monolithic metal substrates: a conventional parallel channel honeycomb structure and a novel 3D-printed structure with a complex gyroid geometry. The effect of the metal substrate geometry is analyzed for several CO2 sources including ideal flue gas atmospheres, the presence of residual CH4 and CO in the flue gas, as well as simulated biogas sources. The advantages of the gyroid-3D complex geometries over the honeycomb structures are shown for all evaluated conditions, providing at the best-case scenario a 14\% improvement of CO2 conversion. Moreover, this contribution shows that systematically tailoring geometrical features of structured catalysts becomes an effective strategy to achieve improved catalysts performances independent of the flue gas composition. By enhancing the transport processes and the gas-catalyst interactions, the employed gyroid 3D metal substrates enable boosted CO2 conversions and greater CH4 selectivity within diffusional controlled regimes.}, language = {en} } @misc{GonzalezCastanoBaenaMorenoNavarrodeMigueletal., author = {Gonz{\´a}lez-Casta{\~n}o, Miriam and Baena-Moreno, Francisco Manuel and Navarro de Miguel, Juan Carlos and Miah, Kamal Uddin Mohammad and Arroyo-Torralvo, F{\´a}tima and Ossenbrink, Ralf and Odriozola, Jos{\´e} Antonio and Benzinger, Walther and Hensel, Andreas and Wenka, Achim and Arellano-Garc{\´i}a, Harvey}, title = {3D-printed structured catalysts for CO2 methanation reaction: Advancing of gyroid-based geometries}, series = {Energy Conversion and Management}, volume = {258}, journal = {Energy Conversion and Management}, issn = {2590-1745}, doi = {10.1016/j.enconman.2022.115464}, pages = {8}, abstract = {This work investigates the CO2 methanation rate of structured catalysts by tuning the geometry of 3D-printed metal Fluid Guiding Elements (FGEs) structures based on periodically variable pseudo-gyroid geometries. The enhanced performance showed by the structured catalytic systems is mostly associated with the capability of the FGEs substrate geometries for efficient heat usages. Thus, variations on the channels diameter resulted in ca. 25\% greater CO2 conversions values at intermediate temperature ranges. The highest void fraction evidenced in the best performing catalyst (3D-1) favored the radial heat transfer and resulted in significantly enhanced catalytic activity, achieving close to equilibrium (75\%) conversions at 400 ◦C and 120 mL/min. For the 3D-1 catalyst, a mathematical model based on an experimental design was developed thus enabling the estimation of its behavior as a function of temperature, spatial velocity, hydrogen to carbon dioxide (H2/CO2) ratio, and inlet CO2 concentration. Its optimal operating conditions were established under 3 different scenarios: 1) no restrictions, 2) minimum H2:CO2 ratios, and 3) minimum temperatures and H2/CO2 ratio. For instance, for the lattest scenario, the best CO2 methanation conditions require operating at 431 ◦C, 200 mL/min, H2/CO2 = 3 M ratio, and inlet CO2 concentration = 10 \%.}, language = {en} }