Pub Date : 2026-01-01DOI: 10.1016/j.jcou.2025.103305
Jakub Halamek , Martin Kubů , Branislav Koreň , Jiří Čejka , Jan Valenta , Roman Bulánek
Adsorption on zeolites reduces CO2 emissions and cuts the energy costs of processing gas mixtures, such as natural gas, biogas, and landfill gas (CO2/CH4 of various concentrations). Among zeolite frameworks, LTA stands out for its CO2 adsorption and/or separation potential, particularly the Na-LTA zeolite with a Si/Al ratio of ∼5. However, the impact of different cations on the separation efficiency of this system remains unknown. In this study, we tested various alkali-metal-exchanged UZM-9 zeolites (Si/Al = 4.5) for their selective adsorption of CO2 over CH4. K+-exchanged UZM-9 reached the highest CO2 affinity, isosteric heat of adsorption, and selectivity, outperforming more commonly used Na+ forms. This enhanced performance likely stems from the predominant location of K+ in the 8-ring window, which fosters strong CO2 interactions, potentially via bridging CO2 species. Due to partial pore blocking, the total uptake may decrease slightly, but the K-UZM-9 system effectively balances CO2/CH4 selectivity and adsorption capacity. Therefore, K-UZM-9 emerges as a promising adsorbent for energy-efficient gas separation and carbon capture applications.
{"title":"Selective CO2 adsorption over alkali metal cation-exchanged UZM-9 zeolites","authors":"Jakub Halamek , Martin Kubů , Branislav Koreň , Jiří Čejka , Jan Valenta , Roman Bulánek","doi":"10.1016/j.jcou.2025.103305","DOIUrl":"10.1016/j.jcou.2025.103305","url":null,"abstract":"<div><div>Adsorption on zeolites reduces CO<sub>2</sub> emissions and cuts the energy costs of processing gas mixtures, such as natural gas, biogas, and landfill gas (CO<sub>2</sub>/CH<sub>4</sub> of various concentrations). Among zeolite frameworks, LTA stands out for its CO<sub>2</sub> adsorption and/or separation potential, particularly the Na-LTA zeolite with a Si/Al ratio of ∼5. However, the impact of different cations on the separation efficiency of this system remains unknown. In this study, we tested various alkali-metal-exchanged UZM-9 zeolites (Si/Al = 4.5) for their selective adsorption of CO<sub>2</sub> over CH<sub>4</sub>. K<sup>+</sup>-exchanged UZM-9 reached the highest CO<sub>2</sub> affinity, isosteric heat of adsorption, and selectivity, outperforming more commonly used Na<sup>+</sup> forms. This enhanced performance likely stems from the predominant location of K<sup>+</sup> in the 8-ring window, which fosters strong CO<sub>2</sub> interactions, potentially <em>via</em> bridging CO<sub>2</sub> species. Due to partial pore blocking, the total uptake may decrease slightly, but the K-UZM-9 system effectively balances CO<sub>2</sub>/CH<sub>4</sub> selectivity and adsorption capacity. Therefore, K-UZM-9 emerges as a promising adsorbent for energy-efficient gas separation and carbon capture applications.</div></div>","PeriodicalId":350,"journal":{"name":"Journal of CO2 Utilization","volume":"103 ","pages":"Article 103305"},"PeriodicalIF":8.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A novel hybrid Cu(30 %)-ZnO(41 %)/Al2O3/MWCNT catalyst was developed to enhance hydrogenation of CO2 to methanol. Multi-walled carbon nanotubes (MWCNTs) were functionalized and incorporated into catalysts with varying carbon contents (0–12 wt%) via co-precipitation. The catalysts were characterized using standard techniques, including XRD, FESEM, TEM, FTIR, Raman spectroscopy, TPR, and CO2-TPD, to evaluate their structural, morphological, and chemical properties. The results demonstrated that MWCNTs integration significantly improved metal dispersion, prevented particle agglomeration, and enhanced CO2 adsorption. The experiments showed that, among all catalyst formulations and the two industrial reference samples, the catalyst with 8 wt% MWCNTs exhibited the highest methanol yield (13.4 %) and a 25 % increase in space–time yield compared to the MWCNT-free catalyst (11.0 %). Furthermore, the catalyst demonstrated excellent long-term stability, preserving its structural integrity and catalytic performance over 60 h of continuous operation. The implementation of this hybrid catalyst as a replacement for the MWCNT-free formulation in the CO2 hydrogenation process resulted in a 6.1 % reduction in total energy demand, which consequently led to a 7.3 % decrease in greenhouse gas emissions (32.5 kg CO2/ton MeOH). These findings confirm that incorporation of MWCNTs constitutes an effective hybrid-support strategy for structural modulation and performance enhancement in CO2 hydrogenation catalysts.
{"title":"Multi-walled carbon nanotube–integrated Cu–ZnO/Al2O3 catalysts: A hybrid support strategy for structural modulation and efficient CO2 hydrogenation to methanol","authors":"Esmaeil GhasemiKafrudi , Navid Mostoufi , Alimorad Rashidi , Reza Zarghami","doi":"10.1016/j.jcou.2025.103306","DOIUrl":"10.1016/j.jcou.2025.103306","url":null,"abstract":"<div><div>A novel hybrid Cu(30 %)-ZnO(41 %)/Al<sub>2</sub>O<sub>3</sub>/MWCNT catalyst was developed to enhance hydrogenation of CO<sub>2</sub> to methanol. Multi-walled carbon nanotubes (MWCNTs) were functionalized and incorporated into catalysts with varying carbon contents (0–12 wt%) via co-precipitation. The catalysts were characterized using standard techniques, including XRD, FESEM, TEM, FTIR, Raman spectroscopy, TPR, and CO<sub>2</sub>-TPD, to evaluate their structural, morphological, and chemical properties. The results demonstrated that MWCNTs integration significantly improved metal dispersion, prevented particle agglomeration, and enhanced CO<sub>2</sub> adsorption. The experiments showed that, among all catalyst formulations and the two industrial reference samples, the catalyst with 8 wt% MWCNTs exhibited the highest methanol yield (13.4 %) and a 25 % increase in space–time yield compared to the MWCNT-free catalyst (11.0 %). Furthermore, the catalyst demonstrated excellent long-term stability, preserving its structural integrity and catalytic performance over 60 h of continuous operation. The implementation of this hybrid catalyst as a replacement for the MWCNT-free formulation in the CO<sub>2</sub> hydrogenation process resulted in a 6.1 % reduction in total energy demand, which consequently led to a 7.3 % decrease in greenhouse gas emissions (32.5 kg CO<sub>2</sub>/ton MeOH). These findings confirm that incorporation of MWCNTs constitutes an effective hybrid-support strategy for structural modulation and performance enhancement in CO<sub>2</sub> hydrogenation catalysts.</div></div>","PeriodicalId":350,"journal":{"name":"Journal of CO2 Utilization","volume":"103 ","pages":"Article 103306"},"PeriodicalIF":8.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-18DOI: 10.1016/j.jcou.2025.103304
Jesse Y. Rumbo-Morales , Felipe D.J. Sorcia-Vázquez , Gerardo Ortiz Torres , Alexis U. Salas Villalobos , Carlos Alberto Torres-Cantero , Manuela Calixto-Rodriguez , Antonio Márquez Rosales , Mayra G. Mena-Enriquez , Mario A. Juarez , Alan Cruz Rojas , Miguel Beltrán-Escobar , Jesús E. Valdez-Resendiz
Biomethane is a renewable energy source obtained by purifying biogas, removing impurities such as H2S and CO2. The removal of H2S is essential due to its toxicity and corrosiveness, protecting equipment and improving process efficiency. Pressure Swing Adsorption (PSA) is used to separate CO2, which produces a methane-rich gas. This process is efficient, clean, and key to utilizing biogas as a substitute for natural gas. This study aims to perform a sensitivity analysis on the H2S removal stage using a packed column with 13X zeolite, and to conduct a parametric study of the PSA process to identify input variables that significantly affect CO2 adsorption and achieve high-purity biomethane (above 99%). Comparative results showed that a pressure of 10 at a temperature of 298 achieved the lowest H2S removal (1100 ), in a period of 4000 ; however, the highest H2S removal was achieved at 2 and 440 , reaching 1500 removal in 900 . In the case of CO2 retention, the input variables that have the least effect on biomethane purity and that present the least adsorption of CO2 were the feed pressure and purge pressure variables, achieving a biomethane purity between the ranges of 97.53 % and 98.86 % and adsorbing between 0.35 to 0.38 molar fraction using only 0.6 of the total bed length. On the other hand, the input variables that achieved the highest adsorption capacity (0.5 molar fraction) were temperature and composition, achieving to use the longest length of the packed bed (0.8 ) and reaching a biomethane purity of 99.05%, which meets established international criteria to be used as biofuel.
{"title":"Sensitivity analysis of the H2S breakthrough curve in a column packed with type 13X zeolite: Parametric study of pressure swing adsorption process for CO2 separation and biomethane production","authors":"Jesse Y. Rumbo-Morales , Felipe D.J. Sorcia-Vázquez , Gerardo Ortiz Torres , Alexis U. Salas Villalobos , Carlos Alberto Torres-Cantero , Manuela Calixto-Rodriguez , Antonio Márquez Rosales , Mayra G. Mena-Enriquez , Mario A. Juarez , Alan Cruz Rojas , Miguel Beltrán-Escobar , Jesús E. Valdez-Resendiz","doi":"10.1016/j.jcou.2025.103304","DOIUrl":"10.1016/j.jcou.2025.103304","url":null,"abstract":"<div><div>Biomethane is a renewable energy source obtained by purifying biogas, removing impurities such as H<sub>2</sub>S and CO<sub>2</sub>. The removal of H<sub>2</sub>S is essential due to its toxicity and corrosiveness, protecting equipment and improving process efficiency. Pressure Swing Adsorption (PSA) is used to separate CO<sub>2</sub>, which produces a methane-rich gas. This process is efficient, clean, and key to utilizing biogas as a substitute for natural gas. This study aims to perform a sensitivity analysis on the H<sub>2</sub>S removal stage using a packed column with 13X zeolite, and to conduct a parametric study of the PSA process to identify input variables that significantly affect CO<sub>2</sub> adsorption and achieve high-purity biomethane (above 99%). Comparative results showed that a pressure of 10 <span><math><mrow><mi>b</mi><mi>a</mi><mi>r</mi></mrow></math></span> at a temperature of 298 <span><math><mi>K</mi></math></span> achieved the lowest H<sub>2</sub>S removal (1100 <span><math><mrow><mi>p</mi><mi>p</mi><mi>m</mi></mrow></math></span>), in a period of 4000 <span><math><mi>s</mi></math></span>; however, the highest H<sub>2</sub>S removal was achieved at 2 <span><math><mrow><mi>b</mi><mi>a</mi><mi>r</mi></mrow></math></span> and 440 <span><math><mi>K</mi></math></span>, reaching 1500 <span><math><mrow><mi>p</mi><mi>p</mi><mi>m</mi></mrow></math></span> removal in 900 <span><math><mi>s</mi></math></span>. In the case of CO<sub>2</sub> retention, the input variables that have the least effect on biomethane purity and that present the least adsorption of CO<sub>2</sub> were the feed pressure and purge pressure variables, achieving a biomethane purity between the ranges of 97.53 % and 98.86 % and adsorbing between 0.35 to 0.38 molar fraction using only 0.6 <span><math><mi>m</mi></math></span> of the total bed length. On the other hand, the input variables that achieved the highest adsorption capacity (0.5 molar fraction) were temperature and composition, achieving to use the longest length of the packed bed (0.8 <span><math><mi>m</mi></math></span>) and reaching a biomethane purity of 99.05%, which meets established international criteria to be used as biofuel.</div></div>","PeriodicalId":350,"journal":{"name":"Journal of CO2 Utilization","volume":"103 ","pages":"Article 103304"},"PeriodicalIF":8.4,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-17DOI: 10.1016/j.jcou.2025.103300
Zhe Wang , Samar Al Jitan , Hassan A. Salih , Cyril Aubry , Thomas Delclos , Inas AlNashef , Khalid Al-Ali , Giovanni Palmisano
Harnessing solar energy to convert liquid carbon dioxide (CO2) into chemical fuels presents a promising solution to address both the greenhouse effect and the fossil fuel crisis. In this study, heterogeneous photocatalysts composed of zinc oxide (ZnO) nanocones and semi-hedgehog-like cupric oxide (CuO) nanoparticles were successfully synthesized via a hydrothermal treatment for efficient photocatalytic reduction of liquid CO2. To further enhance performance, two-dimensional Ti3C2 MXene nanosheets (NSs), corresponding to 5 mol% relative to ZnO, were integrated onto the composite photocatalyst surface, enhancing the specific surface area, facilitating interfacial charge transfer, and promoting the separation of photo-generated electron-hole pairs. Furthermore, 1-Ethyl-3methylimidazolium amino-acetate ionic liquid (IL) was utilized to lower the overpotential and enhance CO2 adsorption and diffusion. This led to a pronounced hydrogenation effect that significantly boosted methane yield in the photocatalytic process. As a result, the ZnO/CuO/Ti3C2 NSs/ILs heterojunction nanocomposite demonstrated significantly enhanced photocatalytic activity for dense-phase CO2 reduction compared to pristine ZnO nanoparticles. Using water as a hydrogen source, ZnO/0.5CuO/Ti3C2 NSs exhibit a very high total yield for liquid CO2 reduction (62 bar and 22 °C), reaching 136.9 mmol h⁻¹ g⁻¹ for CO and 30.2 mmol h⁻¹ g⁻¹ for CH₄ under irradiation of a Xe arc lamp. This remarkable production rate marks a significant step forward in the development of efficient CO2 reduction systems and presents a promising strategy for advancing solar-driven carbon conversion technologies.
{"title":"High-yield solar photocatalytic CO₂ conversion in dense-phase CO₂ via ZnO/CuO/Ti₃C₂ nanosheet heterojunctions with ionic liquids","authors":"Zhe Wang , Samar Al Jitan , Hassan A. Salih , Cyril Aubry , Thomas Delclos , Inas AlNashef , Khalid Al-Ali , Giovanni Palmisano","doi":"10.1016/j.jcou.2025.103300","DOIUrl":"10.1016/j.jcou.2025.103300","url":null,"abstract":"<div><div>Harnessing solar energy to convert liquid carbon dioxide (CO<sub>2</sub>) into chemical fuels presents a promising solution to address both the greenhouse effect and the fossil fuel crisis. In this study, heterogeneous photocatalysts composed of zinc oxide (ZnO) nanocones and semi-hedgehog-like cupric oxide (CuO) nanoparticles were successfully synthesized via a hydrothermal treatment for efficient photocatalytic reduction of liquid CO<sub>2</sub>. To further enhance performance, two-dimensional Ti<sub>3</sub>C<sub>2</sub> MXene nanosheets (NSs), corresponding to 5 mol% relative to ZnO, were integrated onto the composite photocatalyst surface, enhancing the specific surface area, facilitating interfacial charge transfer, and promoting the separation of photo-generated electron-hole pairs. Furthermore, 1-Ethyl-3methylimidazolium amino-acetate ionic liquid (IL) was utilized to lower the overpotential and enhance CO<sub>2</sub> adsorption and diffusion. This led to a pronounced hydrogenation effect that significantly boosted methane yield in the photocatalytic process. As a result, the ZnO/CuO/Ti<sub>3</sub>C<sub>2</sub> NSs/ILs heterojunction nanocomposite demonstrated significantly enhanced photocatalytic activity for dense-phase CO<sub>2</sub> reduction compared to pristine ZnO nanoparticles. Using water as a hydrogen source, ZnO/0.5CuO/Ti<sub>3</sub>C<sub>2</sub> NSs exhibit a very high total yield for liquid CO<sub>2</sub> reduction (62 bar and 22 °C), reaching 136.9 mmol h⁻¹ g⁻¹ for CO and 30.2 mmol h⁻¹ g⁻¹ for CH₄ under irradiation of a Xe arc lamp. This remarkable production rate marks a significant step forward in the development of efficient CO<sub>2</sub> reduction systems and presents a promising strategy for advancing solar-driven carbon conversion technologies.</div></div>","PeriodicalId":350,"journal":{"name":"Journal of CO2 Utilization","volume":"103 ","pages":"Article 103300"},"PeriodicalIF":8.4,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The development of efficient catalysts for CO₂ utilization is a key challenge for industrial sustainability. This study explores the photothermo-catalytic methanation of CO₂ using Ni-Zn-Al Layered Double Hydroxide-derived (LDHd) catalysts modified with phyllosilicates (Montmorillonite K30 and Halloysite). LDH precursors were synthesized by co-precipitation and hydrothermal treatment, then calcined and reduced leading to the formation of mixed oxides and metallic Ni and Zn nanoparticles. Catalytic performances were evaluated at 1 atm and 350 °C. The Ni-Zn-Al LDHd catalyst achieved high CO₂ conversion (86 %) and CH₄ selectivity (>99 %) under photothermo-catalytic conditions, outperforming commercial Ni systems. Incorporation of halloysite, thermally treated at 200 °C, further increased CO₂ conversion to 92 % with the same high CH₄ selectivity. This improved performance is attributed to enhanced surface area, optical absorption and moderate–strong basic sites from LDHd–Halloysite interaction. In contrast, Montmorillonite modification, despite cetyltrimethylammonium bromide (CTAB) intercalation, resulted in lower activity and selectivity, due to weaker basicity and ineffective LDHd interaction. The Ni-Zn-Al LDHd/halloysite catalyst exhibited excellent stability during 20 h of continuous photothermo-catalytic test at 350 °C. These results demonstrate the potential of phyllosilicate-modified LDH-derived catalysts, with low metals content, for efficient CO₂ methanation under solar irradiation.
{"title":"Solar photothermo-catalytic CO2 conversion into methane: Effect of phyllosilicates on the performance of Ni-Zn-Al layered double hydroxide-derived catalysts","authors":"Luca Calantropo , Eleonora La Greca , Leonarda Francesca Liotta , Giuliana Impellizzeri , Antonino Gulino , Angelo Ferlazzo , Libera Vitiello , Sabrina Carola Carroccio , Salvatore Scirè , Roberto Fiorenza","doi":"10.1016/j.jcou.2025.103302","DOIUrl":"10.1016/j.jcou.2025.103302","url":null,"abstract":"<div><div>The development of efficient catalysts for CO₂ utilization is a key challenge for industrial sustainability. This study explores the photothermo-catalytic methanation of CO₂ using Ni-Zn-Al Layered Double Hydroxide-derived (LDHd) catalysts modified with phyllosilicates (Montmorillonite K30 and Halloysite). LDH precursors were synthesized by co-precipitation and hydrothermal treatment, then calcined and reduced leading to the formation of mixed oxides and metallic Ni and Zn nanoparticles. Catalytic performances were evaluated at 1 atm and 350 °C. The Ni-Zn-Al LDHd catalyst achieved high CO₂ conversion (86 %) and CH₄ selectivity (>99 %) under photothermo-catalytic conditions, outperforming commercial Ni systems. Incorporation of halloysite, thermally treated at 200 °C, further increased CO₂ conversion to 92 % with the same high CH₄ selectivity. This improved performance is attributed to enhanced surface area, optical absorption and moderate–strong basic sites from LDHd–Halloysite interaction. In contrast, Montmorillonite modification, despite cetyltrimethylammonium bromide (CTAB) intercalation, resulted in lower activity and selectivity, due to weaker basicity and ineffective LDHd interaction. The Ni-Zn-Al LDHd/halloysite catalyst exhibited excellent stability during 20 h of continuous photothermo-catalytic test at 350 °C. These results demonstrate the potential of phyllosilicate-modified LDH-derived catalysts, with low metals content, for efficient CO₂ methanation under solar irradiation.</div></div>","PeriodicalId":350,"journal":{"name":"Journal of CO2 Utilization","volume":"103 ","pages":"Article 103302"},"PeriodicalIF":8.4,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The solution absorption method is one of the commonly used approaches in Carbon Capture, Utilization, and Storage. The performance and operating parameters of the absorption tower significantly affect CO2 capture efficiency. This study investigated the impact of various input parameters and tower structure on carbon capture efficiency. Findings reveal that among variations in inlet temperatures for both gas and liquid phases, adjusting the absorbent liquid temperature markedly influences capture efficiency, while changes in flue gas inlet temperature have minimal impact. Observing gas-liquid velocity variations shows that reducing both velocities generally increases CO2 capture efficiency; however, for MEA solutions, further reduction below 0.5 m/s leads to decreased efficiency. Additionally, a 10 % CO2 concentration is more easily captured than higher concentrations. Research on packing layer structural characteristics indicates that porosity changes produce opposing effects, with an optimal porosity level of 36 %. Increasing tower height also enhances absorption capacity, with calculations identifying 7 m as the optimal height.
{"title":"Numerical simulation and optimization of a CO2 absorption tower using solution absorption method for capture","authors":"Fengqiang Miao , Xinyu Wang , Hao Wan , Xiangming Zhao , Linyang Zhang , Feng Xu , Dongdong Ren , Jianxiang Guo","doi":"10.1016/j.jcou.2025.103303","DOIUrl":"10.1016/j.jcou.2025.103303","url":null,"abstract":"<div><div>The solution absorption method is one of the commonly used approaches in Carbon Capture, Utilization, and Storage. The performance and operating parameters of the absorption tower significantly affect CO<sub>2</sub> capture efficiency. This study investigated the impact of various input parameters and tower structure on carbon capture efficiency. Findings reveal that among variations in inlet temperatures for both gas and liquid phases, adjusting the absorbent liquid temperature markedly influences capture efficiency, while changes in flue gas inlet temperature have minimal impact. Observing gas-liquid velocity variations shows that reducing both velocities generally increases CO<sub>2</sub> capture efficiency; however, for MEA solutions, further reduction below 0.5 m/s leads to decreased efficiency. Additionally, a 10 % CO<sub>2</sub> concentration is more easily captured than higher concentrations. Research on packing layer structural characteristics indicates that porosity changes produce opposing effects, with an optimal porosity level of 36 %. Increasing tower height also enhances absorption capacity, with calculations identifying 7 m as the optimal height.</div></div>","PeriodicalId":350,"journal":{"name":"Journal of CO2 Utilization","volume":"103 ","pages":"Article 103303"},"PeriodicalIF":8.4,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.jcou.2025.103301
Yassine Bouazzi , Zakarya Ahmed , Saman Ahmad Aminian , Veyan A. Musa , Mohamed Shaban , Narinderjit Singh Sawaran Singh , Wajdi Rajhi , Borhen Louhichi
The use of carbon dioxide as a high-performance working-fluid in advanced thermodynamic cycles provides a compelling route for developing low-carbon, multi-output renewable-energy systems. The study develops and assesses an advanced hybrid solar–geothermal polygeneration facility designed to produce electricity, hydrogen, and freshwater under the real resource conditions of the Harrat Rahat geothermal zone in Saudi Arabia. The configuration combines a double-flash geothermal cycle with a Transcritical CO2 Rankine cycle, a Kalina cycle, an alkaline electrolyser, and a reverse-osmosis desalination unit, supported by parabolic trough solar thermal augmentation. A full 3E+S evaluation—covering energy, exergy, economic, and sustainability metrics—is carried out alongside multi-objective optimization using the Secretary Bird metaheuristic algorithm. Under the real resource inputs of the Harrat Rahat site—geothermal reservoir temperatures exceeding 220 °C and mean solar irradiance of ∼6.6 kWh m−2 day−1, the results show the system could deliver 3.65 MW of net electricity, 9.35 kg.h−1 of hydrogen, and 10.23 m3.h−1 of freshwater, with overall energy and exergy efficiencies of 42.7 % and 38.18 %. Optimization enhances exergy efficiency by about 1.54 % and lowers the levelized cost of energy by roughly 2.2 %, yielding an LCOE of 0.04039 USD/MJ and a sustainability index of 0.238. Exergy-destruction profiling shows that condensers (≈47 %) and the solar thermal subsystem (≈16 %) are the main contributors to irreversibility. Overall, the results indicate that integrating high-enthalpy geothermal resources with concentrated solar power and advanced thermodynamic cycles can deliver a robust, efficient, and economically competitive polygeneration pathway suited to arid regions with strong energy and water needs.
{"title":"Advanced solar–geothermal polygeneration system for CO2-based power, hydrogen, and freshwater recovery via transcritical CO2 rankine cycle","authors":"Yassine Bouazzi , Zakarya Ahmed , Saman Ahmad Aminian , Veyan A. Musa , Mohamed Shaban , Narinderjit Singh Sawaran Singh , Wajdi Rajhi , Borhen Louhichi","doi":"10.1016/j.jcou.2025.103301","DOIUrl":"10.1016/j.jcou.2025.103301","url":null,"abstract":"<div><div>The use of carbon dioxide as a high-performance working-fluid in advanced thermodynamic cycles provides a compelling route for developing low-carbon, multi-output renewable-energy systems. The study develops and assesses an advanced hybrid solar–geothermal polygeneration facility designed to produce electricity, hydrogen, and freshwater under the real resource conditions of the Harrat Rahat geothermal zone in Saudi Arabia. The configuration combines a double-flash geothermal cycle with a Transcritical CO<sub>2</sub> Rankine cycle, a Kalina cycle, an alkaline electrolyser, and a reverse-osmosis desalination unit, supported by parabolic trough solar thermal augmentation. A full 3E+S evaluation—covering energy, exergy, economic, and sustainability metrics—is carried out alongside multi-objective optimization using the Secretary Bird metaheuristic algorithm. Under the real resource inputs of the Harrat Rahat site—geothermal reservoir temperatures exceeding 220 <sup>°</sup>C and mean solar irradiance of ∼6.6 kWh m<sup>−2</sup> day<sup>−1</sup>, the results show the system could deliver 3.65 MW of net electricity, 9.35 kg.h<sup>−1</sup> of hydrogen, and 10.23 m<sup>3</sup>.h<sup>−1</sup> of freshwater, with overall energy and exergy efficiencies of 42.7 % and 38.18 %. Optimization enhances exergy efficiency by about 1.54 % and lowers the levelized cost of energy by roughly 2.2 %, yielding an LCOE of 0.04039 USD/MJ and a sustainability index of 0.238. Exergy-destruction profiling shows that condensers (≈47 %) and the solar thermal subsystem (≈16 %) are the main contributors to irreversibility. Overall, the results indicate that integrating high-enthalpy geothermal resources with concentrated solar power and advanced thermodynamic cycles can deliver a robust, efficient, and economically competitive polygeneration pathway suited to arid regions with strong energy and water needs.</div></div>","PeriodicalId":350,"journal":{"name":"Journal of CO2 Utilization","volume":"103 ","pages":"Article 103301"},"PeriodicalIF":8.4,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.jcou.2025.103295
I-Jeong Jeon , Da-Bin Kang , Jae-Hak Lim , Ji-Hyeon Gong , Chang-Hyeon Kim , Min-Ju Kim , Min-Jun Kim , Kyung-Won Jeon , Ik Seon Kwon , Won-Jun Jang , Chang Hyun Ko , Jae-Oh Shim
The CO2 hydrogenation reaction is a promising route for mitigating greenhouse gas emissions by converting CO2 into value-added carbon monoxide through the reverse water–gas shift (RWGS) process. In this study, a surfactant-assisted mechanochemical synthesis was developed to prepare highly dispersed Cu catalysts supported on MgCeOx for the RWGS reaction. The combined use of CTAB (Hexadecyltrimethylammonium bromide, C19H42BrN) and Span®60 (Sorbitan monostearate, C24H46O6) enabled simultaneous control of Cu dispersion, oxygen vacancy concentration, and Ce3 + enrichment under solvent-minimized conditions. The optimized Cu@MgCeOx_CS catalyst achieved 25 % CO2 conversion and complete stability at 440 °C under a gas hourly space velocity (GHSV) of 50,000 h−1 with an H2/CO2 ratio of 4:1. Enhanced redox coupling between Cu+/Cu2 and Ce3+/Ce4+ was verified by precise X-ray analyses, confirming that Cu⁺ species act as the main active sites. This study demonstrates a scalable and energy-efficient route for the synthesis of uniformly mixed Cu–MgO–CeO2 catalysts and provides mechanistic insight into the relationship between surface redox properties and RWGS performance.
{"title":"Application of highly dispersed copper catalysts in CO2 hydrogenation through surfactant introduction","authors":"I-Jeong Jeon , Da-Bin Kang , Jae-Hak Lim , Ji-Hyeon Gong , Chang-Hyeon Kim , Min-Ju Kim , Min-Jun Kim , Kyung-Won Jeon , Ik Seon Kwon , Won-Jun Jang , Chang Hyun Ko , Jae-Oh Shim","doi":"10.1016/j.jcou.2025.103295","DOIUrl":"10.1016/j.jcou.2025.103295","url":null,"abstract":"<div><div>The CO<sub>2</sub> hydrogenation reaction is a promising route for mitigating greenhouse gas emissions by converting CO<sub>2</sub> into value-added carbon monoxide through the reverse water–gas shift (RWGS) process. In this study, a surfactant-assisted mechanochemical synthesis was developed to prepare highly dispersed Cu catalysts supported on MgCeO<sub>x</sub> for the RWGS reaction. The combined use of CTAB (Hexadecyltrimethylammonium bromide, C<sub>19</sub>H<sub>42</sub>BrN) and Span®60 (Sorbitan monostearate, C<sub>24</sub>H<sub>46</sub>O<sub>6</sub>) enabled simultaneous control of Cu dispersion, oxygen vacancy concentration, and Ce<sup>3 +</sup> enrichment under solvent-minimized conditions. The optimized Cu@MgCeO<sub>x</sub>_CS catalyst achieved 25 % CO<sub>2</sub> conversion and complete stability at 440 °C under a gas hourly space velocity (GHSV) of 50,000 h<sup>−1</sup> with an H<sub>2</sub>/CO<sub>2</sub> ratio of 4:1. Enhanced redox coupling between Cu<sup>+</sup>/Cu<sup>2</sup> and Ce<sup>3+</sup>/Ce<sup>4+</sup> was verified by precise X-ray analyses, confirming that Cu⁺ species act as the main active sites. This study demonstrates a scalable and energy-efficient route for the synthesis of uniformly mixed Cu–MgO–CeO<sub>2</sub> catalysts and provides mechanistic insight into the relationship between surface redox properties and RWGS performance.</div></div>","PeriodicalId":350,"journal":{"name":"Journal of CO2 Utilization","volume":"103 ","pages":"Article 103295"},"PeriodicalIF":8.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.jcou.2025.103298
Ting Kong , Kefan Zhou , Jingnan Wang , Qiyi Zhao , Aizhen Liao , Xiaoshuang Qiao
Urea (NH₂CONH₂) plays a crucial role as both a nitrogen-based fertilizer and a key industrial raw material. Its conventional synthesis typically requires harsh conditions. In contrast, the electrocatalytic conversion of nitrogen (N₂) and carbon dioxide (CO₂) into urea has emerged as a promising alternative. However, achieving catalysts that offer both high activity and selectivity is still a huge challenge. This study utilizes density functional theory for investigating the electrochemical coupling between N₂ and CO₂ for the production of urea, specifically examining the performance of various transition metal clusters (from Groups IB and VIII) supported on C₂N catalysts. The results revealed that these catalysts demonstrate strong thermodynamic stability and effectively facilitate the co-adsorption of CO₂ and N₂. Notably, except Pd and Pt, most M₃/C₂N catalysts efficiently suppress the H2 evolution reaction, preventing the excessive protonation of CO and the generation of ammonia, thus guaranteeing high selectivity for urea. In particular, Ru₃ and Os₃/C₂N catalysts demonstrate lower free energies and promote C-N coupling via *N₂ and *CO intermediates. Further evaluation of the electronic structure of Os₃/C₂N revealed an "acceptance-donation" mechanism that enhanced the activation of *CO₂ and *N₂, with the Os₃ cluster playing a crucial role. This research provides a new approach for electrochemically synthesizing urea and offers valuable insights into the design of advanced electrocatalysts.
{"title":"Electrochemical production of urea using triatomic cluster/C2N catalysts: A DFT study","authors":"Ting Kong , Kefan Zhou , Jingnan Wang , Qiyi Zhao , Aizhen Liao , Xiaoshuang Qiao","doi":"10.1016/j.jcou.2025.103298","DOIUrl":"10.1016/j.jcou.2025.103298","url":null,"abstract":"<div><div>Urea (NH₂CONH₂) plays a crucial role as both a nitrogen-based fertilizer and a key industrial raw material. Its conventional synthesis typically requires harsh conditions. In contrast, the electrocatalytic conversion of nitrogen (N₂) and carbon dioxide (CO₂) into urea has emerged as a promising alternative. However, achieving catalysts that offer both high activity and selectivity is still a huge challenge. This study utilizes density functional theory for investigating the electrochemical coupling between N₂ and CO₂ for the production of urea, specifically examining the performance of various transition metal clusters (from Groups IB and VIII) supported on C₂N catalysts. The results revealed that these catalysts demonstrate strong thermodynamic stability and effectively facilitate the co-adsorption of CO₂ and N₂. Notably, except Pd and Pt, most M₃/C₂N catalysts efficiently suppress the H<sub>2</sub> evolution reaction, preventing the excessive protonation of CO and the generation of ammonia, thus guaranteeing high selectivity for urea. In particular, Ru₃ and Os₃/C₂N catalysts demonstrate lower free energies and promote C-N coupling via *N₂ and *CO intermediates. Further evaluation of the electronic structure of Os₃/C₂N revealed an \"acceptance-donation\" mechanism that enhanced the activation of *CO₂ and *N₂, with the Os₃ cluster playing a crucial role. This research provides a new approach for electrochemically synthesizing urea and offers valuable insights into the design of advanced electrocatalysts.</div></div>","PeriodicalId":350,"journal":{"name":"Journal of CO2 Utilization","volume":"103 ","pages":"Article 103298"},"PeriodicalIF":8.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.jcou.2025.103294
Xinyang Li , Guilong Wang , Xiebin Wang , Guoqun Zhao
Microcellular foaming is one of the most promising method for preparing high-performance polymer foams. Gas diffusion and adsorption behavior can significantly affect the foaming behavior of polymers in microcellular foaming. However, it is still a challenging work to manipulate the gas diffusion and adsorption behavior for achieving desired performance of polymer foams. Herein, a novel pre-foaming strategy was proposed to manipulate carbon dioxide adsorption and desorption behavior for achieving low-density thermoplastic polyurethane (TPU) foams. It was demonstrated that pre-foaming is an efficient method for manipulating the diffusion and adsorption behavior of carbon dioxide in TPU matrix. Thanks to the newly created cellular structure by pre-foaming, both diffusion coefficient and adsorption amount increase gradually with increasing the pre-foamed expansion ratio of TPU. For the pre-foamed expansion ratio of 2.0, the gas solubility was increased by 92.8 %, the diffusion coefficients in adsorption and desorption were increased by 54.0 % and 111.0 %, respectively. Interestingly, pre-foaming can lead to a more perfect crystal structure, while destroying the hydrogen bond structure of TPU chains. Owing to the significantly increased gas adsorption capacity and greatly reduced cell growth resistance, the pre-foaming strategy can lead to remarkably increased expansion ratio of the TPU foams. All the TPU foams prepared without pre-foaming have a maximum expansion ratio less than 4, while those prepared with pre-foaming can have an expansion ratio larger than 16. This new microcellular foaming technique with pre-foaming provides a novel approach for preparing low-density thermoplastic elastomer foams.
{"title":"A novel pre-foaming strategy to manipulate carbon dioxide adsorption and desorption behavior for achieving low-density TPU foams","authors":"Xinyang Li , Guilong Wang , Xiebin Wang , Guoqun Zhao","doi":"10.1016/j.jcou.2025.103294","DOIUrl":"10.1016/j.jcou.2025.103294","url":null,"abstract":"<div><div>Microcellular foaming is one of the most promising method for preparing high-performance polymer foams. Gas diffusion and adsorption behavior can significantly affect the foaming behavior of polymers in microcellular foaming. However, it is still a challenging work to manipulate the gas diffusion and adsorption behavior for achieving desired performance of polymer foams. Herein, a novel pre-foaming strategy was proposed to manipulate carbon dioxide adsorption and desorption behavior for achieving low-density thermoplastic polyurethane (TPU) foams. It was demonstrated that pre-foaming is an efficient method for manipulating the diffusion and adsorption behavior of carbon dioxide in TPU matrix. Thanks to the newly created cellular structure by pre-foaming, both diffusion coefficient and adsorption amount increase gradually with increasing the pre-foamed expansion ratio of TPU. For the pre-foamed expansion ratio of 2.0, the gas solubility was increased by 92.8 %, the diffusion coefficients in adsorption and desorption were increased by 54.0 % and 111.0 %, respectively. Interestingly, pre-foaming can lead to a more perfect crystal structure, while destroying the hydrogen bond structure of TPU chains. Owing to the significantly increased gas adsorption capacity and greatly reduced cell growth resistance, the pre-foaming strategy can lead to remarkably increased expansion ratio of the TPU foams. All the TPU foams prepared without pre-foaming have a maximum expansion ratio less than 4, while those prepared with pre-foaming can have an expansion ratio larger than 16. This new microcellular foaming technique with pre-foaming provides a novel approach for preparing low-density thermoplastic elastomer foams.</div></div>","PeriodicalId":350,"journal":{"name":"Journal of CO2 Utilization","volume":"103 ","pages":"Article 103294"},"PeriodicalIF":8.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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