Integration of CO2 Capture and Utilization: Comparison
Please note this is a comparison between Version 2 by Camila Xu and Version 1 by Cuijuan Zhang.

Integrated CO2 capture and utilization aims to capture CO2 from gas streams and other emission sources and convert it into valuable chemicals or energy sources. The key is to find the match between the CO2 separation process and the CO2 utilization process, including the temperature and pressure, etc. CO2 can be captured via physical or chemical absorption depending on the interaction between CO2 and the absorbent. 

  • carbon neutrality
  • CO2 capture
  • CO2 conversion
  • integration

1. Introduction

Carbon dioxide capture, utilization, and storage (CCUS) are increasingly gaining global attention. The challenge is to meet the energy demand while balancing CO2 emissions. Several solutions have been proposed to reduce the CO2 emission, namely, increasing the utilization of eco-friendly energy sources, such as wind and solar energy, to improve the energy efficiency. However, the advancement of such technologies is currently still limited and can be an optimal option in the long-term. At present times, the CCUS technology is more effective and can be a short-term alternative.
CO2 can be captured using various technologies, such as amine absorption, porous materials adsorption and membrane separation. Since CO2 itself is a carbon source, it can be converted into valuable chemicals via dry methane reforming (DMR), CO2 hydrogenation, reverse water–gas shift reaction, etc. There are excellent reviews on both the technologies [1,2,3][1][2][3]. However, the traditional CO2 capture and utilization processes are separated, which inevitably increases the transportation cost. To reduce or even eliminate such cost, the integration of CO2 capture and utilization is greatly desirable.

2. Integration of CO2 Capture and Utilization

Integrated CO2 capture and utilization aims to capture CO2 from gas streams and other emission sources and convert it into valuable chemicals or energy sources. The key is to find the match between the CO2 separation process and the CO2 utilization process, including the temperature and pressure, etc.

2.1. Integration of CO


Absorption and Conversion

CO2 can be captured via physical or chemical absorption depending on the interaction between CO2 and the absorbent. The former mainly utilizes the solubility of each gas component in the solvent whereas the latter involves chemical reactions between CO2 and the absorbent. Chemical absorption is mostly employed with organic amine, hot potash, and liquid ammonia solvents considering its easy operation and mild working conditions [4]. Accordingly, it can be integrated with CO2 hydrogenation for the production of formic acid or methanol. Amine-based CO2 capture and conversion integrated reactors consist of a series of amine sorbents and metal ions that form a pincer complex, such as pincerpentaethylenehexamine (PEHA), pyrrolizidine, N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDTA) and polyethyleneimine (PEI). These are coupled with metal pincer-based homogeneous catalysts [5,6,7,8][5][6][7][8]. Due to the presence of multiple amine sites [9], PEI can be used as a superior CO2 absorber [10], which can absorb both high and low concentrations of CO2 [11]. Li et al. [12] used PEI/RhCl3·3H2O/CyPPh2 to capture CO2 and convert it in situ (Figure 1a). PEI absorbs CO2 from air in an ethylene glycol solution containing PEI and converts it into amino formate esters and alkyl carbonate esters. CO2 is hydrogenated in situ to form formate salts (TON = 260) in the presence of RhCl3-3H2O/CyPPh2, demonstrating the first in situ CO2 capture and conversion to formate. Multifunctional materials can be synthesized by modifying the PEI backbone with iminophosphine ligand functionality and subsequently metallizing it with Ir precursors. About 65% of the available primary amines on PEI can be modified to form iminophosphine/Ir (PN/Ir) for balanced CO2 capture and conversion, resulting in higher formic acid yields. PEI with relatively lower molecular weight has better CO2 capture ability and catalytic activity (Figure 1b) [13]. Kothandaraman et al. [14] reported, for the first time, a green and simplified method for in situ conversion of captured CO2 to formate in aqueous media in the presence of Ru- and Fe-based pincer complexes without excess alkali, with yields of up to 95% of the formate.
Figure 1. (a) Proposed pathways of carbon capture and subsequent hydrogenation of the captured CO2 [12]; (b) Formic acid yields in the hydrogenation of CO2 catalyzed by the PEI–PN/Ir materials as a function of temperature and MW of PEI for PEI600–PN/Ir (▪), PEI1800–PN/Ir (•), and PEI25 000–PN/Ir (▴) [13]. (c) Multiple recycling of the catalyst in biphasic reaction mixture. Yield (%) of formate is relative to the amount of CO2 captured. Ru–PNP 1: Cat 1 = 10 μmol, T = 55 °C, H2 = 50 bar, 17.2 mmol diazabicyclo[2.2.2]octane (DABCO) + 3 mL H2O (CO2 captured each cycle = 15 mmol), 3 mL additional H2O–4 mL 2-Methyltetrahydrofuran (2–MeTHF) added for hydrogenation study. Fe–PNP 4: Cat 4 = 20 μmol, T = 55 °C, H2 = 50 bar, 17.2 mmol DABCO + 3 mL H2O (CO2 captured each cycle = 15 mmol), 3 mL additional H2O–4 mL 2–MeTHF added for hydrogenation study [14]. (d) Proposed reaction sequence for CO2 capture and in situ hydrogenation to CH3OH using a polyamine [5].
In addition to formate, the captured CO2 can be converted into methanol. In 2015, Rezayee et al. [15] prepared methanol by tandem CO2 capture and in situ conversion of dimethylamine with homogeneous ruthenium complexes under basic conditions. Dimethylamine can react with CO2 and inhibit the formation of formic acid. The conversion of CO2 is >95% (Figure 1c). Moreover, Kothandaraman et al. [5] first proposed and demonstrated a system for capturing CO2 from air (~400 ppm) and converting it in situ (Figure 1d), which consisted of PEHA and Ru–PNP complex, with a methanol yield of 79%. Integrated systems for CO2 capture and conversion into methanol are still uncommon. The major obstacle is the harsh reaction conditions to produce methanol, which involves a high-pressure gas-phase catalyst reactor at relatively low temperatures of 200–300 °C and high pressures of 50–100 atm. The amine-based materials offer the potential to capture and convert CO2 under mild conditions. Due to the relatively high CO2 capture capacity of PEI, it can directly capture CO2 from the air, which also removes the limitation of constructing CO2 capture equipment. However, the high selectivity of some materials to carbon dioxide poses a challenge for the regeneration of amines. Furthermore, the toxicity and corrosiveness of amine solvents limit their industrial application. To drive future research, it is essential to explore systems that are highly efficient and recyclable, enabling CCU to establish a reliable foundation for industrial applications.

2.2. CO


Adsorption and Conversion Integration

Similar to absorption, adsorption separation can also be divided into chemisorption and physisorption according to the interaction between CO2 and the adsorbate, with the former forming covalent bonds whilst the latter forms bond with electrostatic attraction and van der Waals forces.  Porous organic polymers (POPs) are a series of new two- or three-dimensional networked polymeric materials formed by covalent bonding of organic small molecule substrates through specific chemical reactions, usually with microporous, mesoporous or multistage pore structures. They have promising applications in separation, sensor and catalysis [16]. The ionic porous organic polymers (IPOPs) are generally classified as porous organic materials, whose backbone typically includes anions or cations. They can be divided into IPOPs with cationic moieties, IPOPs with anionic moieties, and IPOPs with zwitterionic moieties. Common cationic moieties include imidazolium, pyridinium, viologen, and quaternary phosphonium, whereas more common anionic moieties include tetrakis(phenyl)borate and tris(catecholate) phosphate. The inclusion of these ionic moieties in porous materials can enhance their CO2 capture capacity and catalyze the in situ CO2 conversion. In 2011, tetrakis(4-ethynylphenyl)methane and diiodoimidazolium salts were used to prepare tubular microporous organic via Sonogashira coupling reaction networks bearing imidazolium salts (T-IM) (Figure 2a). The material, with a microporous structure of specific surface area (620 m2 g−1), shows good catalytic activity towards the conversion of CO2 to cyclic carbonates [17]. Wang et al. [18] utilized the Friedel–Crafts reaction to synthesize imidazole-based IPOPs. The specific surface area can reach up to 926 m2 g−1; however, its CO2 capture capacity is only 14.2 wt%. Nevertheless, the polymer exhibits good stability and repeatability. Sun et al. [19] demonstrated, for the first time, the capture and in situ conversion of CO2 into cyclic carbonates under relatively mild room temperature conditions using a metal-free solvent followed by a heterogeneous catalytic system. The effect of halogen anions (Cl, Br, and I) and quaternary phosphonium cations on the catalytic activity was investigated. The catalytic activity follows the order Cl > Br > I (Figure 2b), because the rate-controlling step of the reaction is ring opening by anion attack on the epoxide [20].
Figure 2. (a) Preparation of porous organic networks bearing imidazolium salts [17]; (b) Yields of chloropropene carbonate from the cycloaddition of epichlorohydrin and CO2 catalyzed by PIPs with corresponding QPs and PIP-Me-X, PIP-Et-X, and PIP-Bn-X (X = Cl, Br, and I). Reaction conditions: epichlorohydrin (1.0 g, 10.9 mmol), catalyst (0.05 mmol, based upon the quaternary phosphonium salt), 323 K, CO2 (ambient pressure), and 24 h [19].
In addition to IPOP, the porphyrin-based organic polymer (POP-TPP) can also be used. Xiao et al. [21] synthesized a hierarchically porous organic polymer (POP-TPP) by polymerizing vinyl-functionalized tetraphenylporphyrin monomer, and then metalated it with different metals (Co3+, Zn2+, and Mg2+). The resulting heterogeneous catalysts have rich active sites and exhibit higher activity than the homogenous Co/TPP catalyst at relatively low CO2 concentrations, primarily due to the favorable enrichment of CO2 in the porous structure (micropores and nanochannels) of Co/POP-TPP. The TOF of the catalysts decreases in the following order: Co/POP-TPP (436 h−1) > Zn/POP-TPP (326 h−1) > Mg/POP-TPP (171 h−1) (Table 1). Later, a series of high surface area hollow tubular metal (Al, Co, Fe, and Mn) porphyrin-based hypercrosslinked polymers (HCP) were synthesized via Friedel–Crafts alkylation reactions. Al-HCP can catalyze the formation of propylene carbonate with a selectivity of approximately 99% after only 1 h with 2.0 mol% TBAB catalyst [22].
Table 1.
Cycloaddition of epichlorohydrin with CO
to form cyclic carbonate over various catalysts at 29 °C [21].


  1. Song, K.S.; Fritz, P.W.; Coskun, A. Porous organic polymers for CO2 capture, separation and conversion. Chem. Soc. Rev. 2022, 51, 9831–9852.
  2. Zhang, P.; Tong, J.; Huang, K.; Zhu, X.; Yang, W. The current status of high temperature electrochemistry-based CO2 transport membranes and reactors for direct CO2 capture and conversion. Prog. Energy Combust. Sci. 2021, 82, 100888.
  3. Yamada, H. Amine-based capture of CO2 for utilization and storage. Polym. J. 2021, 53, 93–102.
  4. Maina, J.W.; Pringle, J.M.; Razal, J.M.; Nunes, S.; Vega, L.; Gallucci, F.; Dumée, L.F. Strategies for integrated capture and conversion of CO2 from dilute flue gases and the atmosphere. ChemSusChem 2021, 14, 1805–1820.
  5. Kothandaraman, J.; Goeppert, A.; Czaun, M.; Olah, G.A.; Prakash, G.S. Conversion of CO2 from air into methanol using a polyamine and a homogeneous ruthenium catalyst. J. Am. Chem. Soc. 2016, 138, 778–781.
  6. Kar, S.; Goeppert, A.; Prakash, G.S. Combined CO2 capture and hydrogenation to methanol: Amine immobilization enables easy recycling of active elements. ChemSusChem 2019, 12, 3172–3177.
  7. Hanusch, J.M.; Kerschgens, I.P.; Huber, F.; Neuburger, M.; Gademann, K. Pyrrolizidines for direct air capture and CO2 conversion. Chem. Commun. 2019, 55, 949–952.
  8. Guan, C.; Pan, Y.; Ang, E.P.L.; Hu, J.; Yao, C.; Huang, M.-H.; Li, H.; Lai, Z.; Huang, K.-W. Conversion of CO2 from air into formate using amines and phosphorus-nitrogen PN 3P-Ru (ii) pincer complexes. Green Chem. 2018, 20, 4201–4205.
  9. Tailor, R.; Abboud, M.; Sayari, A. Supported polytertiary amines: Highly efficient and selective SO2 adsorbents. Environ. Sci. Technol. 2014, 48, 2025–2034.
  10. Yang, S.; Zhan, L.; Xu, X.; Wang, Y.; Ling, L.; Feng, X. Graphene-based porous silica sheets impregnated with polyethyleneimine for superior CO2 capture. Adv. Mater. 2013, 25, 2130–2134.
  11. Goeppert, A.; Czaun, M.; May, R.B.; Prakash, G.S.; Olah, G.A.; Narayanan, S. Carbon dioxide capture from the air using a polyamine based regenerable solid adsorbent. J. Am. Chem. Soc. 2011, 133, 20164–20167.
  12. Li, Y.-N.; He, L.-N.; Liu, A.-H.; Lang, X.-D.; Yang, Z.-Z.; Yu, B.; Luan, C.-R. In situ hydrogenation of captured CO2 to formate with polyethyleneimine and Rh/monophosphine system. Green Chem. 2013, 15, 2825–2829.
  13. McNamara, N.D.; Hicks, J.C. CO2 capture and conversion with a multifunctional polyethyleneimine-tethered iminophosphine iridium catalyst/adsorbent. ChemSusChem 2014, 7, 1114–1124.
  14. Kothandaraman, J.; Goeppert, A.; Czaun, M.; Olah, G.A.; Prakash, G.S. CO2 capture by amines in aqueous media and its subsequent conversion to formate with reusable ruthenium and iron catalysts. Green Chem. 2016, 18, 5831–5838.
  15. Rezayee, N.M.; Huff, C.A.; Sanford, M.S. Tandem amine and ruthenium-catalyzed hydrogenation of CO2 to methanol. J. Am. Chem. Soc. 2015, 137, 1028–1031.
  16. Zhang, T.; Xing, G.; Chen, W.; Chen, L. Porous organic polymers: A promising platform for efficient photocatalysis. Mater. Chem. Front. 2020, 4, 332–353.
  17. Cho, H.C.; Lee, H.S.; Chun, J.; Lee, S.M.; Kim, H.J.; Son, S.U. Tubular microporous organic networks bearing imidazolium salts and their catalytic CO2 conversion to cyclic carbonates. Chem. Commun. 2011, 47, 917–919.
  18. Wang, J.; Sng, W.; Yi, G.; Zhang, Y. Imidazolium salt-modified porous hypercrosslinked polymers for synergistic CO2 capture and conversion. Chem. Commun. 2015, 51, 12076–12079.
  19. Sun, Q.; Jin, Y.; Aguila, B.; Meng, X.; Ma, S.; Xiao, F.S. Porous ionic polymers as a robust and efficient platform for capture and chemical fixation of atmospheric CO2. ChemSusChem 2017, 10, 1160–1165.
  20. Smith, J.G. Organic Chemistry, 3rd ed.; McGraw-Hill: Singapore, 2011.
  21. Dai, Z.; Sun, Q.; Liu, X.; Bian, C.; Wu, Q.; Pan, S.; Wang, L.; Meng, X.; Deng, F.; Xiao, F.-S. Metalated porous porphyrin polymers as efficient heterogeneous catalysts for cycloaddition of epoxides with CO2 under ambient conditions. J. Catal. 2016, 338, 202–209.
  22. Chen, Y.; Luo, R.; Xu, Q.; Zhang, W.; Zhou, X.; Ji, H. State-of-the-art aluminum porphyrin-based heterogeneous catalysts for the chemical fixation of CO2 into cyclic carbonates at ambient conditions. ChemCatChem 2017, 9, 767–773.
  23. Zhai, G.; Liu, Y.; Lei, L.; Wang, J.; Wang, Z.; Zheng, Z.; Wang, P.; Cheng, H.; Dai, Y.; Huang, B. Light-promoted CO2 conversion from epoxides to cyclic carbonates at ambient conditions over a Bi-based metal–organic framework. ACS Catal. 2021, 11, 1988–1994.
  24. Ding, M.; Jiang, H.-L. Incorporation of imidazolium-based poly (ionic liquid)s into a metal–organic framework for CO2 capture and conversion. ACS Catal. 2018, 8, 3194–3201.
  25. Dai, W.; Li, Q.; Long, J.; Mao, P.; Xu, Y.; Yang, L.; Zou, J.; Luo, X. Hierarchically mesoporous imidazole-functionalized covalent triazine framework: An efficient metal-and halogen-free heterogeneous catalyst towards the cycloaddition of CO2 with epoxides. J. CO2 Util. 2022, 62, 102101.
  26. Liu, F.; Duan, X.; Dai, X.; Du, S.; Ma, J.; Liu, F.; Liu, M. Metal-decorated porous organic frameworks with cross-linked pyridyl and triazinyl as efficient platforms for CO2 activation and conversion under mild conditions. Chem. Eng. J. 2022, 445, 136687.
  27. Ma, P.; Ding, M.; Zhang, Y.; Rong, W.; Yao, J. Integration of lanthanide-imidazole containing polymer with metal-organic frameworks for efficient cycloaddition of CO2 with epoxides. Sep. Purif. Technol. 2023, 313, 123498.
  28. Rui, Z.; Ji, H.; Lin, Y.S. Modeling and analysis of ceramic-carbonate dual-phase membrane reactor for carbon dioxide reforming with methane. Int. J. Hydrogen Energy 2011, 36, 8292–8300.
  29. Anderson, M.; Lin, Y.S. Carbon dioxide separation and dry reforming of methane for synthesis of syngas by a dual-phase membrane reactor. AlChE J. 2013, 59, 2207–2218.
  30. Pakhare, D.; Spivey, J. A review of dry (CO2) reforming of methane over noble metal catalysts. Chem. Soc. Rev. 2014, 43, 7813–7837.
  31. Zhang, P.; Tong, J.; Huang, K. Combining electrochemical CO2 capture with catalytic dry methane reforming in a single reactor for low-cost syngas production. ACS Sustain. Chem. Eng. 2016, 4, 7056–7065.
  32. Zhang, P.; Tong, J.; Huang, K. Dry-oxy methane reforming with mixed e(-)/CO32- conducting membranes. ACS Sustain. Chem. Eng. 2017, 5, 5432–5439.
  33. Zhang, P.; Tong, J.; Huang, K. Role of CO2 in catalytic ethane-to-ethylene conversion using a high-temperature CO2 transport membrane reactor. ACS Sustain. Chem. Eng. 2019, 7, 6889–6897.
  34. Chen, T.J.; Wang, Z.G.; Liu, L.N.; Pati, S.; Wai, M.H.; Kawi, S. Coupling CO2 separation with catalytic reverse water-gas shift reaction via ceramic-carbonate dual-phase membrane reactor. Chem. Eng. J. 2020, 379, 122182.
  35. Xing, W.; Peters, T.; Fontaine, M.-L.; Evans, A.; Henriksen, P.P.; Norby, T.; Bredesen, R. Steam-promoted CO2 flux in dual-phase CO2 separation membranes. J. Membr. Sci. 2015, 482, 115–119.
  36. Wu, H.C.; Rui, Z.B.; Lin, J.Y.S. Hydrogen production with carbon dioxide capture by dual-phase ceramic-carbonate membrane reactor via steam reforming of methane. J. Membr. Sci. 2020, 598, 117780.
  37. Ovalle-Encinia, O.; Wu, H.C.; Chen, T.J.; Lin, J.Y.S. CO2-permselective membrane reactor for steam reforming of methane. J. Membr. Sci. 2022, 641, 119914.
  38. Li, X.; Huang, K.; Van Dam, N.; Jin, X. Performance projection of a high-temperature CO2 transport membrane reactor for combined CO2 capture and methane-to-ethylene conversion. J. Electrochem. Soc. 2022, 169, 053501.
  39. Zhang, K.; Sun, S.; Huang, K. Oxidative coupling of methane (OCM) conversion into C2 products through a CO2/O2 co-transport membrane reactor. J. Membr. Sci. 2022, 661, 120915.
  40. Zhang, P.; Tong, J.; Huang, K. Self-formed, mixed-conducting, triple-phase membrane for efficient CO2/O2 capture from flue gas and in situ dry-oxy methane reforming. ACS Sustain. Chem. Eng. 2018, 6, 14162–14169.
  41. Fabian-Anguiano, J.A.; Mendoza-Serrato, C.G.; Gomez-Yanez, C.; Zeifert, B.; Ma, X.; Ortiz-Landeros, J. Simultaneous CO2 and O2 separation coupled to oxy-dry reforming of CH4 by means of a ceramic-carbonate membrane reactor for in situ syngas production. Chem. Eng. Sci. 2019, 210, 115250.
  42. Fabian-Anguiano, J.A.; Ramirez-Moreno, M.J.; Balmori-Ramirez, H.; Romero-Serrano, J.A.; Romero-Ibarra, I.C.; Ma, X.; Ortiz-Landeros, J. Syngas production with CO2 utilization through the oxidative reforming of methane in a new cermet-carbonate packed-bed membrane reactor. J. Membr. Sci. 2021, 637, 119607.
  43. Shao, B.; Zhang, Y.; Sun, Z.; Li, J.; Gao, Z.; Xie, Z.; Hu, J.; Liu, H. CO2 capture and in-situ conversion: Recent progresses and perspectives. Green Chem. Eng. 2022, 3, 189–198.
  44. Sun, S.; Sun, H.; Williams, P.T.; Wu, C. Recent advances in integrated CO2 capture and utilization: A review. Sustain. Energy Fuels 2021, 5, 4546–4559.
  45. Zhang, W.; Ma, D.; Pérez-Ramírez, J.; Chen, Z. Recent progress in materials exploration for thermocatalytic, photocatalytic, and integrated photothermocatalytic CO2-to-fuel conversion. Adv. Energy Sustain. Res. 2022, 3, 2100169.
  46. Kim, S.M.; Abdala, P.M.; Broda, M.; Hosseini, D.; Copéret, C.; Müller, C. Integrated CO2 capture and conversion as an efficient process for fuels from greenhouse gases. ACS Catal. 2018, 8, 2815–2823.
  47. Tian, S.; Yan, F.; Zhang, Z.; Jiang, J. Calcium-looping reforming of methane realizes in situ CO2 utilization with improved energy efficiency. Sci. Adv. 2019, 5, eaav5077.
  48. Hu, J.; Hongmanorom, P.; Chirawatkul, P.; Kawi, S. Efficient integration of CO2 capture and conversion over a Ni supported CeO2-modified CaO microsphere at moderate temperature. Chem. Eng. J. 2021, 426, 130864.
  49. Wang, G.; Guo, Y.; Yu, J.; Liu, F.; Sun, J.; Wang, X.; Wang, T.; Zhao, C. Ni-CaO dual function materials prepared by different synthetic modes for integrated CO2 capture and conversion. Chem. Eng. J. 2022, 428, 132110.
  50. Sun, H.; Wang, J.; Zhao, J.; Shen, B.; Shi, J.; Huang, J.; Wu, C. Dual functional catalytic materials of Ni over Ce-modified CaO sorbents for integrated CO2 capture and conversion. Appl. Catal. B Environ. 2019, 244, 63–75.
  51. Duyar, M.S.; Trevino, M.A.A.; Farrauto, R.J. Dual function materials for CO2 capture and conversion using renewable H2. Appl. Catal. B Environ. 2015, 168, 370–376.
  52. Arellano-Treviño, M.A.; He, Z.; Libby, M.C.; Farrauto, R.J. Catalysts and adsorbents for CO2 capture and conversion with dual function materials: Limitations of Ni-containing DFMs for flue gas applications. J. CO2 Util. 2019, 31, 143–151.
  53. Porta, A.; Visconti, C.G.; Castoldi, L.; Matarrese, R.; Jeong-Potter, C.; Farrauto, R.; Lietti, L. Ru-Ba synergistic effect in dual functioning materials for cyclic CO2 capture and methanation. Appl. Catal. B Environ. 2021, 283, 119654.
  54. Bermejo-López, A.; Pereda-Ayo, B.; González-Marcos, J.; González-Velasco, J. Mechanism of the CO2 storage and in situ hydrogenation to CH4. Temperature and adsorbent loading effects over Ru-CaO/Al2O3 and Ru-Na2CO3/Al2O3 catalysts. Appl. Catal. B Environ. 2019, 256, 117845.
  55. Bermejo-López, A.; Pereda-Ayo, B.; González-Marcos, J.; González-Velasco, J. Ni loading effects on dual function materials for capture and in-situ conversion of CO2 to CH4 using CaO or Na2CO3. J. CO2 Util. 2019, 34, 576–587.
  56. Al-Mamoori, A.; Rownaghi, A.A.; Rezaei, F. Combined capture and utilization of CO2 for syngas production over dual-function materials. ACS Sustain. Chem. Eng. 2018, 6, 13551–13561.
  57. Duyar, M.S.; Wang, S.; Arellano-Trevino, M.A.; Farrauto, R.J. CO2 utilization with a novel dual function material (DFM) for capture and catalytic conversion to synthetic natural gas: An update. J. CO2 Util. 2016, 15, 65–71.
  58. Garbarino, G.; Bellotti, D.; Riani, P.; Magistri, L.; Busca, G. Methanation of carbon dioxide on Ru/Al2O3 and Ni/Al2O3 catalysts at atmospheric pressure: Catalysts activation, behaviour and stability. Int. J. Hydrogen Energy 2015, 40, 9171–9182.
  59. Wang, S.; Schrunk, E.T.; Mahajan, H.; Farrauto, R.J. The role of ruthenium in CO2 capture and catalytic conversion to fuel by dual function materials (DFM). Catalysts 2017, 7, 88.
  60. Wang, S.; Farrauto, R.J.; Karp, S.; Jeon, J.H.; Schrunk, E.T. Parametric, cyclic aging and characterization studies for CO2 capture from flue gas and catalytic conversion to synthetic natural gas using a dual functional material (DFM). J. CO2 Util. 2018, 27, 390–397.