Publications

@article{ZAMBRANOJUCA2027124691,

title = {Proposal of a metric for catalyst comparison: Application to catalysts for methanol synthesis from CO2},

author = {Daniel Zambrano-Juca and Miguel Menéndez},

url = {https://www.sciencedirect.com/science/article/pii/S0009250926014065},

doi = {https://doi.org/10.1016/j.ces.2026.124691},

issn = {0009-2509},

year  = {2027},

date = {2027-01-01},

journal = {Chemical Engineering Science},

volume = {338},

pages = {124691},

abstract = {Comparing the performance of different catalysts becomes challenging when the experimental data have been obtained under varying experimental conditions (temperature, pressure, spatial velocity…). A system where a huge amount of experimental data has been published, but under widely different experimental conditions, is the catalytic hydrogenation of CO2 to methanol, which would be a key process for CO2 upgrading and for the production of sustainable fuels. This work introduces a new metric based on the calculation of the relative activity (a*) and relative selectivity (s*) with respect to a reference catalyst, using kinetics equations from literature and a plug flow reactor model. For this reaction an industrially relevant catalyst (Cu/ZnO/Al2O3) has been chosen as reference catalyst, a wide review of literature data was performed and, after applying a filter for thermodynamic feasibility, the values of relative activity (a*) and selectivity (s*) for each catalyst were calculated. Eleven groups of catalyst have been analyzed and compared using this methodology, and significative trends were found in this meta-analysis. Systems based on Cu (including promotors as Zr, Y, W or Al) show significative improvements in a* and/or s* over the reference catalyst. Ga-promoted catalysts, particularly the Cu-Ga systems, show more relative selectivity (s*> 3) than most of the studied catalyst. Systems based on In2O3, in particular with Pd doping (with s*>2 and good activity), ZnZrOx as catalyst and as support, and innovative solids such as CdZrOx (with a* > 70 and s* > 1.5), emerge as the most attractive platforms to achieve high intrinsic selectivity. The proposed methodology could be extended to other reaction systems of interest, providing a useful approach for screening the most suitable catalyst for a given reaction.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{GONZALEZPIZARRO2026182703,

title = {Sorption Enhanced reverse Water Gas Shift (SErWGS): Optimal potassium-driven methanol suppression and zeolite type selection (LTA and FAU) under high-pressure conditions},

author = {R. González-Pizarro and S. Renda and J. Lasobras and J. Soler and M. Menéndez and J. Herguido},

url = {https://www.sciencedirect.com/science/article/pii/S1385894726101661},

doi = {https://doi.org/10.1016/j.cej.2026.182703},

issn = {1385-8947},

year  = {2026},

date = {2026-01-01},

journal = {Chemical Engineering Journal},

volume = {549},

pages = {182703},

abstract = {CO hydrogenation is thermodynamically and kinetically more favorable than direct CO2 hydrogenation, making a preceding CO2-to-CO conversion step an attractive route for enhancing e-fuel production. In this work, intensified e-syngas production via high-pressure CO2 hydrogenation was investigated through the Sorption-Enhanced Reverse Water-Gas Shift (SErWGS) process. Particular attention was given to methanol suppression through the incorporation of low potassium loadings in the catalyst, and to the influence of zeolite type on process performance. The effect of potassium loading on catalytic activity and CH3OH inhibition was systematically evaluated under different temperatures and WHSV values using a Design of Experiments (DoE) methodology, which enabled the development of empirical models describing the process behavior and identification of the optimal catalyst formulation. In parallel, the performance of different zeolite adsorbents was assessed to maximize H2O removal and process intensification. The optimized catalyst, containing 1.5 wt% K, effectively suppressed methanol formation while maximizing CO production. The intensified SErWGS process achieved CO yields exceeding the thermodynamic equilibrium limit at the operating temperature. H2/CO ratios approaching those expected for complete CO2-to-CO conversion, and pre-breakthrough periods accounting for up to 80% of the total cycle duration. The highest CO yield obtained in this work reached 42% at 260 °C using the 3A-LTA zeolite, corresponding to a value approximately 2.5 times higher than that achieved under conventional RWGS conditions. Remarkably, this CO yield was comparable to the thermodynamic equilibrium yield expected at approximately 450 °C in a conventional rWGS process. These results validate that the SErWGS strategy can deliver performance equivalent to operating nearly 200 °C above the actual reaction temperature, highlighting its potential as an effective intensification approach for low-temperature CO2 conversion and sustainable e-syngas production.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{GONZALEZPIZARRO2026109731,

title = {LTA and FAU zeolites as water and CO₂ sorbents for sorption-enhanced CO₂ hydrogenation (SECO2H): Low-pressure sorption-enhanced methanol synthesis as a case study},

author = {R. González-Pizarro and V. D. Mercader and P. Durán and S. Renda and J. Soler and J. A. Peña and M. Menéndez and J. Herguido},

url = {https://www.sciencedirect.com/science/article/pii/S0957582026013492},

doi = {https://doi.org/10.1016/j.psep.2026.109731},

issn = {0957-5820},

year  = {2026},

date = {2026-01-01},

journal = {Process Safety and Environmental Protection},

volume = {221},

pages = {109731},

abstract = {The selection of the zeolite used in a sorption enhanced CO2 hydrogenation process (SECO2H) plays a decisive role in determining the extent of process intensification and the resulting product yields. This selection is governed by several key properties, including zeolite acidity, pore aperture, adsorption capacity, and the selective adsorption of the target reaction product. Among the zeolites investigated, namely 3 A, 4 A, 5 A (LTA framework), and 13X (FAU framework), the last one exhibited the highest CO2 and H2O adsorption capacities. However, LTA-3A provided the highest selectivity and affinity towards H2O adsorption. H2O adsorption also appeared stronger than CO2 adsorption, as complete H2O desorption and zeolite regeneration required more severe desorption conditions than those needed for CO2 removal. Sorption-enhanced methanol synthesis (SEMS) was selected as the target reaction to evaluate the effect of these zeolites on CO2 hydrogenation. Among all the materials studied, only LTA-3A provided a pronounced intensification of the process, increasing both CH3OH and CO yields due to its highly selective H2O adsorption. The SEMS experiments assisted by LTA-3A delivered yields above the conventional thermodynamic limits of the conventional process and outperformed reported values under comparatively mild operating conditions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{MERCADER2026136698,

title = {Intensifying synthetic natural gas production by functionalization of a NiFe/γ-Al2O3 catalyst with alkaline and alkaline-earth materials},

author = {V. D. Mercader and P. Sanz-Monreal and P. Durán and P. Aragüés-Aldea and E. Francés and J. Herguido and J. A. Peña},

url = {https://www.sciencedirect.com/science/article/pii/S0016236125024238},

doi = {https://doi.org/10.1016/j.fuel.2025.136698},

issn = {0016-2361},

year  = {2026},

date = {2026-01-01},

journal = {Fuel},

volume = {406},

pages = {136698},

abstract = {This study demonstrates the influence of the functionalization method (Mechanical Mixture -MM- and Dual Function Materials -DFM-) of two CO2 adsorbent species (Na and Ca) in a catalytic fixed-bed reactor for CO2 methanation. The experiments consisted of cycles beginning with a CO2 adsorption stage followed by a methanation stage (with H2), interspersed with or without inert purge periods. The greatest enhancement in methane generation was observed in experiments with a mechanical mixture (MM) of NiFe/γ-Al2O3 catalyst and Na2O/γ-Al2O3. The methane production capacity was tested over a temperature range comprised between 200 and 400 °C, with values over 380 μmol/g obtained under moderate conditions (350 °C and pCO2 = 0.12 bar) and selectivity to methane close to 100 %. Since the ultimate goal is the methanation of the CO2 present in a biogas (without removing CH4), the potential effect of the presence of methane during the CO2 adsorption stages was also investigated. To achieve this task, a feed stream representative of a sweetened biogas coming from the anaerobic decomposition of municipal solid waste (MSW) (70 %v CH4 and 30 %v CO2) was used. The results showed no adverse effects along the successive cycles, paving the way to the use of these solids for biogas upgrading. On the other hand, the catalyst did not show a significant loss of activity after several hours of repetitive adsorption-methanation cycles.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{GONZALEZPIZARRO2026136974,

title = {Tuning e-fuel selectivity in sorption-enhanced CO2 hydrogenation over In2O3/ZrO2: The effect of LTA and FAU zeolites},

author = {R. González-Pizarro and R. Calero-Berrocal and J. Lasobras and S. Renda and M. R. Rodríguez-Pardo and J. Soler and M. Menéndez and J. Herguido},

url = {https://www.sciencedirect.com/science/article/pii/S0016236125026997},

doi = {https://doi.org/10.1016/j.fuel.2025.136974},

issn = {0016-2361},

year  = {2026},

date = {2026-01-01},

journal = {Fuel},

volume = {406},

pages = {136974},

abstract = {The e-fuels synthesis via CO2 hydrogenation and the Sorption Enhanced Reaction technology are captivating strategies for CO2 utilization and the integration of renewable energy sources. This study focuses on enhancing the conversion of CO2 over an In2O3/ZrO2 catalyst by incorporating LTA zeolites (3A and 4A) and a FAU zeolite (13X). Key operational parameters, such as temperature (T), Gas Hour Space Velocity (GHSV), type of zeolite, and Zeolite: Catalyst mass ratio (Z/C), were systematically varied. LTA zeolites (3A and 4A) provided the highest CO2 conversions. The introduction of a water-adsorbing solid into the reactor significantly altered the products yield and selectivity. While the selectivity towards CH4, CH3OH, and C2H6O appeared to lay on the type of zeolite, the selectivity towards CO remained unaffected. Zeolite 3A demonstrated the greatest enhancement in selectivity towards CH4 and CH3OH, whereas the synthesis of C2H6O was favored by zeolites 4A and 13X. The Zeolite:Catalyst mass ratio also played a crucial role in process performance, influencing both CO2 conversion and product selectivity. Increasing this ratio improved CO2 conversion and reduced CO selectivity under all operating conditions, while CH4 selectivity increased. However, the selectivity toward CH3OH and C2H6O exhibited an anomalous and complementary behavior. While a maximum was observed for DME, a minimum was registered in methanol production, suggesting a dependency of the dehydration reaction kinetics on the amount of water produced during the reaction.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{RENDA2026120682,

title = {Doped In2O3/ZrO2 catalysts to drive selectivity toward DME in one-pot CO2 hydrogenation},

author = {Simona Renda and Jaime Soler and Miguel Menéndez and Javier Herguido},

url = {https://www.sciencedirect.com/science/article/pii/S0926860X25005848},

doi = {https://doi.org/10.1016/j.apcata.2025.120682},

issn = {0926-860X},

year  = {2026},

date = {2026-01-01},

journal = {Applied Catalysis A: General},

volume = {710},

pages = {120682},

abstract = {This study investigates single-pass dimethyl ether synthesis at mild pressure conditions using novel bifunctional catalysts based on indium-modified formulations and incorporating Ni, Cu, Pt, and Pd as active metals. Additionally, the substitution of the conventional HZSM-5 zeolite with 4A zeolite as the dehydration component was evaluated. Although 4A zeolite exhibited lower dehydration activity, it contributed to an overall improvement in DME selectivity. The incorporation of secondary metals into the In2O3-ZrO2 formulation reduced catalytic activity but enhanced selectivity, ultimately increasing DME yield. The formation of by-products such as light olefins and methane was significantly dependent on the metal used: Ni, Pt, and Pd reduced olefin production, though Ni promoted excessive methane formation across the whole temperature range. Notably, the Pt-based catalyst completely suppressed by-product formation across the temperature range studied. While the In2O3-ZrO2-based catalysts generally displayed lower space–time yields than the commercial reference, they achieved comparable performance at 280 °C. Due to their superior selectivity, these formulations are promising for developing even better performing catalysts, to be excellent candidates in industrial processes, where the operation with recycle loops requires a high product purity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{GONZALEZPIZARRO2026137642,

title = {Low loading copper-based catalysts for effective CO2 hydrogenation to methanol},

author = {R. González-Pizarro and S. Renda and J. Lasobras and J. Soler and M. Menéndez and J. Herguido},

url = {https://www.sciencedirect.com/science/article/pii/S001623612503368X},

doi = {https://doi.org/10.1016/j.fuel.2025.137642},

issn = {0016-2361},

year  = {2026},

date = {2026-01-01},

journal = {Fuel},

volume = {408},

pages = {137642},

abstract = {Methanol synthesis via CO2 hydrogenation is an emerging Power-to-Liquid (PtL) technology aimed to accelerate the energy transition and the defossilization of key sectors, particularly maritime transport. This study focuses on the study of low loading formulations, to minimize the catalyst cost. Key operational variables including temperature (T), Weight Hourly Space Velocity (WHSV), copper and zinc loadings, and aging state were systematically varied. An overall active phase loading of 10 %wt emerged as optimal. Within this total loading, a 5 %wtCu-5 %wtZn/ZrO2 catalysts delivered higher methanol productivity than 10 %wtCu/ZrO2; however, the bimetallic catalysts showed pronounced deactivation under water-rich atmospheres, establishing 10 %wtCu/ZrO2 as the most promising catalysts. Operating temperature and WHSV exerted a strong, synergistic influence on CH3OH formation; in particular, increasing WHSV shifted the reaction away from thermodynamic control and boosted methanol synthesis. Finally, the catalytic performance of these low-loading catalysts was benchmarked against high-copper-loading methanol catalysts reported in the literature by critically compare their activities as a function of the residence time (τ) calculated at reaction conditions. This assessment revealed that the proposed formulation is highly competitive when compared to most conventional formulation, with a maximum methanol space time yield (STYCH3OH) of 3.9 gCH3OH gCu-1 h-1. This comparison confirms that the catalysts proposed in this study could offer a remarkably more efficient use of the active phase than the conventional high-copper-loading catalysts.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{GONZALEZPIZARRO2026138902,

title = {Overcoming thermodynamic limitations of the low-temperature reverse water-gas shift in a sorption-enhanced fluidized bed reactor with continuous sorbent feeding and separation (SEFBR + CSF)},

author = {R. González-Pizarro and J. Lasobras and S. Renda and J. Soler and M. Menéndez and J. Herguido},

url = {https://www.sciencedirect.com/science/article/pii/S1383586626021684},

doi = {https://doi.org/10.1016/j.seppur.2026.138902},

issn = {1383-5866},

year  = {2026},

date = {2026-01-01},

journal = {Separation and Purification Technology},

volume = {404},

pages = {138902},

abstract = {Abstract 

This work presents a novel approach for intensifying the reverse water gas shift (rWGS) reaction by integrating an advanced fluidized-bed reactor design with a continuous solid sorbent feeding/separation strategy. The proposed Sorption Enhanced Fluidized Bed Reactor combined with Continuous Sorbent Feeding and Separation (SEFBR + CSF) enables continuous operation while maintaining the intensification effect traditionally associated with temporal-limited sorption-enhanced processes. This configuration externalizes the regeneration of the water-adsorbing zeolite, which is continuously and selectively withdrawn from the reactor in a partially or fully saturated state and replaced with regenerated material, thereby sustaining the sorption capacity throughout operation. Process intensification was experimentally demonstrated in the SEFBR + CSF configuration, which achieved CO yields significantly higher than those obtained in the conventional fluidized-bed reactor (cFBR). During the interval in which continuous sorbent feeding was applied, CO production surpassed the thermodynamic equilibrium limit at operating temperatures between 260 and 300 °C. When compared with literature data under similar conditions, the proposed system exhibited superior CO yields, particularly in the low-temperature regime where conventional LT-rWGS performance is typically limited. Overall, the SEFBR + CSF system represents a promising pathway for continuous sorption-enhanced operation, providing improved efficiency and enabling the process to exceed the equilibrium constraints of the LT-rWGS reaction.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{ARAGUESALDEA2026115899,

title = {Packed-bed membrane reactors as a strategy for selective CO2 methanation},

author = {P. Aragüés-Aldea and P. Durán and V. D. Mercader and S. Renda and E. Francés and J. A. Peña and J. Herguido},

url = {https://www.sciencedirect.com/science/article/pii/S0920586126002233},

doi = {https://doi.org/10.1016/j.cattod.2026.115899},

issn = {0920-5861},

year  = {2026},

date = {2026-01-01},

journal = {Catalysis Today},

volume = {476},

pages = {115899},

abstract = {CO2 methanation represents a key route within Power-to-X strategies for converting captured carbon into synthetic natural gas. However, its efficiency is limited by thermodynamic constraints, heat management issues, and undesired CO formation due to the reverse water–gas shift reaction. In this work, a novel packed-bed membrane reactor (PBMR), conceived as an evolution of the polytropic packed-bed reactor (PPBR), is proposed and experimentally validated for selective CO2 methanation. The reactor enables distributed reactant feeding through a porous membrane wall, allowing enhanced control over local reaction environments along the catalytic bed. A Ni–Fe/Al2O3 catalyst was employed and tested under various operating conditions, including different weight hourly space velocities (WHSV) and feeding configurations (conventional, co-current, and counter-current). The influence of distributing either H2 or CO2 was systematically investigated in terms of CO2 conversion, temperature profiles, and CO selectivity. While distributed configurations did not improve overall CO2 conversion compared to conventional operation, they significantly affected selectivity. In particular, CO2-distributed feeding consistently reduced CO selectivity under iso-conversion conditions, achieving up to a 40% decrease in the most favorable case. This significant reduction highlights the effectiveness of spatial reactant management in driving the reaction pathway toward methane. Overall, these results underline the critical role of reactor design in overcoming selectivity limitations and demonstrate the potential of membrane-assisted distributed feeding as a process intensification strategy for CO2 methanation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{ARAGUESALDEA2025103038,

title = {Biogas upgrading through CO2 methanation in a multiple-inlet fixed bed reactor: Simulated parametric analysis},

author = {P. Aragüés-Aldea and V. D. Mercader and P. Durán and E. Francés and J. Á. Peña and J. Herguido},

url = {https://www.sciencedirect.com/science/article/pii/S2212982025000228},

doi = {https://doi.org/10.1016/j.jcou.2025.103038},

issn = {2212-9820},

year  = {2025},

date = {2025-01-01},

journal = {Journal of CO2 Utilization},

volume = {93},

pages = {103038},

abstract = {A simulation of the catalytic CO2 methanation reaction was carried out, evaluating the effect of reactants distributed feeding throughout the bed. The main operational parameters were studied in a multiple-inlet reactor to test their effect on conversions and, most importantly, on selectivities towards both CO and CH4 as reaction products. The analyzed parameters were, firstly, the number of feeding points (N) and the dosage degree of reactants, followed by temperature (T), partial pressures of reactants (H2:CO2 ratios), and the composition of a sweetened biogas as feeding stream (CH4:CO2 ratios). It is confirmed that a distribution of biogas through several side inlets improves selectivities to the desired CH4 product, over other feeding configurations. The effect of distributing reactants becomes intensified when the number of lateral feedings increases. This observation supports the experimental trends already proven in previous works. Regarding main operation parameters such as temperature and H2:CO2 molar ratio, the analysis confirmed that their influence on selectivities acts just as predicted at low conversions. However, when these conversions become higher the space velocity (WHSV) is the most important factor for selectivities. Finally, no significant changes in reaction performance were obtained when modifying the biogas CH4:CO2 ratio in the broad range of methane concentrations from 55 v% to 70 v%.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{RENDA2025107764,

title = {Effect of particles size and density on the segregation of catalyst-sorbent mixtures for direct sorption-enhanced DME synthesis: Experimental and mathematical study},

author = {Simona Renda and Jaime Soler and Javier Herguido and Miguel Menéndez},

url = {https://www.sciencedirect.com/science/article/pii/S0961953425001758},

doi = {https://doi.org/10.1016/j.biombioe.2025.107764},

issn = {0961-9534},

year  = {2025},

date = {2025-01-01},

journal = {Biomass and Bioenergy},

volume = {197},

pages = {107764},

abstract = {Direct sorption-enhanced dimethyl ether synthesis (SEDMES) is a promising process for the production of fuels from CO2 sources. Using novel technologies, the process can be run exploiting the phenomena of particles segregation in a fluidized bed reactor. However, the knowledge on the solid movement and the segregation patterns is a mandatory preliminary step for the setup of the final application. In this study, we evaluated the impact of particles size and density on the segregation patterns, and we used the Gibilaro and Rowe (GR) model to analytically represent the experimental results. It was observed that the variation of both parameters influences segregation, even though a higher separation degree in a wider operating velocity range was observed when a higher density ratio was induced between the two solids. Through the experimental analysis, five possible bed configurations were identified, and a consideration was made on the aims of the GR model to adjust the mathematical representation to the present case. By considering the bottom portion of the bed as a jetsam-rich phase and not – as previously reported – as a segregated layer, a mass balance on the catalyst allowed to obtain a faithful analytical representation of the experimental segregation patterns.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}