Highly Selective Conversion of Carbon Dioxide to Lower Olefins - ACS

Nov 13, 2017 - ... Chizhou Tang, Shu Miao, Zhaochi Feng, Hongyu An, and Can Li. State Key Laboratory of Catalysis, Dalian Institute of Chemical Physic...
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Highly Selective Conversion of Carbon Dioxide to Lower Olefins Zelong Li, Jijie Wang, Yuanzhi Qu, Hailong Liu, Chizhou Tang, Shu Miao, Zhaochi Feng, Hongyu An, and Can Li ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.7b03251 • Publication Date (Web): 13 Nov 2017 Downloaded from http://pubs.acs.org on November 13, 2017

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Highly Selective Conversion of Carbon Dioxide to Lower Olefins Zelong Li, Jijie Wang, Yuanzhi Qu, Hailong Liu, Chizhou Tang, Shu Miao, Zhaochi Feng, Hongyu An, Can Li* State Key Laboratory of Catalysis, Institution Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China Supporting Information

ABSTRACT: Conversion of CO2 to value-added chemicals has been a long-standing objective, direct hydrogenation of CO2 to lower olefins is highly desirable, but still challenging. Herein, we report a selective conversion of CO2 to lower olefins through CO2 hydrogenation over a ZnZrO/SAPO tandem catalyst fabricated with a ZnO-ZrO2 solid solution and a Zn-modified SAPO-34 zeolite, which can achieve the lower olefins selectivity as high as 80-90% among hydrocarbon products. This is realized based on the dual functions of the tandem catalyst: hydrogenation of CO2 on the ZnO-ZrO2 solid solution and lower olefins production on the SAPO zeolite. The thermodynamic and kinetic coupling between the tandem reactions enable the highly efficient conversion of CO2 to lower olefins. Furthermore, this catalyst is stable toward the thermal and sulfur treatments, showing the potential industrial application. KEYWORDS: tandem catalysis • CO2 hydrogenation •C-C coupling • thermodynamic coupling • solid solution oxide.

CO2 has turned out to be a strategic carbon resource for the synthesis of valued chemicals rather than just a greenhouse gas1-4. Utilization of CO2 as a feedstock for synthesis of chemicals is emerging as a complementary alternative to fossil-derived chemicals5-9. The proposal on carbon capture and utilization (CCU) is receiving increasingly attention worldwide10-15. Lower olefins as basic carbon-based building blocks, commonly referring to ethylene, propylene, and butylenes (C2=-C4=), are mainly produced from cracking of hydrocarbon feed stocks like naphtha16 and dehydrogenation of light alkanes17-18. Lower olefins synthesis is a practical solution to CO2 storage as olefins can be stored in the form of polymer materials19. Although hydrogenation of CO to lower olefins20-29, alkenes30 and aromatics31-32 has been made progress, as far as we know, the hydrogenation of CO2 to lower olefins with high selectivity is rarely reported. CO2 is located at the bottom of the energetic ladder in thermodynamics, and the reaction of CO2 requires considerable Gibbs energy input (the Gibbs formation energy,

ΔG. (CO2) = -394.4 KJ mol-1). Hydrogenation of CO2 makes the reaction possible in thermodynamics and practically significant when H2 is supplied from renewable energy. However, the activation energy barriers of reactions involved with CO2 are always very high. Active catalysts are prerequisites for CO2 hydrogenation, which must enable the activation of both H2 and CO2. In this regard, Cu-based catalysts33-39 and several newly reported metalbased40-45 and metal oxide-based46-48 catalysts have shown good performance in methanol synthesis from CO2 hydrogenation. It is well known that the C-C bond formation can take place on zeolite catalyst in methanol

conversion, such as hydrocarbons formation on HZSM549-50 and lower olefins on SAPO-3451-53. Hydrogenation of CO2 on the composites catalysts such as Cu-ZnCr/zeolite54 and CuZnOZrO2/zeolite55 gives the products mainly included alkanes and CO. Recently, ZnCrOx/MSAPO bifunctional catalyst was used to convert syngas to lower olefins with high selectivity (80% of hydrocarbons) through the gas phase transferring of ketene as intermediate26. Later, the Zr-Zn (2:1) binary oxide coupled with SAPO-34 offers around 70% selectivity for lower olefins at about 10% CO conversion, and methanol or methoxide as intermediates were proposed23. Compared with hydrogenation of CO to lower olefins by using bifunctional catalysts, the first key difference of CO2 hydrogenation over bifunctional catalyst (methanol synthesis catalyst/zeolite) is the reverse water-gas shift reaction (RWGS) that occured in the reaction of CO2 hydrogenation, which is kinetically favored and can resulit in the producing of amounts of CO under reaction conditions of bifunctional catalyst. In addition, the H2O that formed by CO2 hydrogenation on methanol synthesis catalyst can seriously affect the activity and stabilty of zeolite for realizing C-C bond formation. Therefore synthesis of lower olefins with high selectivity from CO2 hydrogenation over bifunctional catalyst is very challenge. It was reported that CO2 hydrogenation on Na modified Fe-based Fischer-Tropsch catalyst56 and In2O3 catalyst57 combined with H-ZSM-5 exhibited excellent selectivity in gasoline, and a CeO2−Pt@mSiO2−Co tandem catalyst with two metal-oxide interfaces converted CO2 to C2−C4 hydrocarbons with 60% selectivity58. However, the goal of achieving high selectivity in lower olefins while

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suppressing alkane and CO productions has not been achieved. In this work, we developed a ZnO-ZrO2 mixed metal oxide catalyst which shows considerable methanol selectivity at wide temperatures, and a Zn-modified SAPO which can initiate the methanol to olefins reaction. Our proposal is to synthesize the lower olefins by taking the advantages of these two types of catalysis: CO2 hydrogenation to methanol and selective conversion of methanol to lower olefins. Therefore, by considering these dual functional catalysis and chemical engineering factors, we fabricated a tandem catalyst by dispersing the ZnO-ZrO2 nanoparticles on the SAPO micro-meter crystals for the CO2 hydrogenation. The particle size of ZnO-ZrO2 is in the range of 10~30 nm (Figure 1a) and HAADF-STEM shows that Zn and Zr elements are homogeneously distributed in ZnO-ZrO2 particles (Figure 1b). XRD patterns (Figure 1c) of the ZnOZrO2 (with ZnO molar contents, 7%, 13% to 20%, the ZnO-ZrO2 catalyst used in this work contains 13% ZnO, hereafter noted as ZnZrO) show the same phase structure of tetragonal ZrO2, indicating that the ZnZrO is in solid solution structure, Raman spectra also confirm that the ZnZrO is in tetragonal phase (Figure S1a). The prepared Zn-doped SAPO-34 (hereafter noted as SAPO) with CHA framework structure (Figure S2) is highly crystalline and shows the cuboid crystals ranged from 2 to 5 μm (Figure 1d, S3). The tandem catalyst was prepared by physical mixing of ZnZrO and SAPO (hereafter refereed to ZnZrO/SAPO) and the two components keep their individual structures (Figure S2). The ZnO-ZrO2 particle size is much smaller than SAPO, so the ZnZrO particles are highly dispersed on the outer surface of the SAPO in ZnZrO/SAPO (Figure 1e, schematic in Figure 1f).

Figure 1. Catalyst characterization: a) TEM and HRTEM images of ZnZrO; b) Aberration-corrected HAADF-STEM images and element distribution of Zn and Zr for ZnZrO; c) XRD patterns of ZnO, t-ZrO2 and ZnOZrO2; d) SEM image of SAPO; e) SEM image of ZnZrO/SAPO; f) Schematic description of ZnZrO/SAPO.

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Figure. 2a (left panel) shows a representative result that the CO2 hydrogenation on the ZnZrO/SAPO gives 80% selectivity of C2=-C4=, 14% C2-C40, 3% CH4, and 3% C5+ among all hydrocarbon products, at the CO2 single pass conversion of 12.6% under reaction condition of 2 MPa, 3600 mL/gcat/h, and 380 oC, and CO selectivity is suppressed to 47%. CO2 hydrogenation over the ZnZrO mainly produces methanol and CO, while neither olefins nor methanol was detected for SAPO alone, indicating that it is the tandem catalyst that efficiently converts CO2 to lower olefins. Figure 2a (right panel) shows that methanol conversion on SAPO or ZnZrO/SAPO produces lower olefins with high selectivity (over 90%), affirms that SAPO is the catalyst for methanol to lower olefins conversion. These results lead us to the conclusion that tandem reactions take place on the tandem catalyst, ZnZrO/SAPO, where the ZnZrO generates methanol (and precursors) from CO2 hydrogenation and the SAPO is responsible for the methanol to lower olefins conversion.

Figure 2. Catalytic performance in CO2 hydrogenation: a) CO2 hydrogenation on ZnZrO/SAPO, ZnZrO and SAPO and methanol conversion on ZnZrO/SAPO and SAPO; b) CO2 conversion over ZnZrO/SAPO, hydrocarbon distribution and CO selectivity at different reaction temperatures; c) Hydrocarbon distribution and CO2 conversion over ZnZrO/SAPO with different space velocity; d) Stability test for ZnZrO/SAPO. Reaction condition for ZnZrO/SAPO: 380 oC, 2 MPa, 3600 mL/gcat/h; ZnZrO: 330 o C, 2 MPa, 3600 mL/gcat/h (different from 380 oC, the reaction temperature for lower olefins production, where the methanol selectivity is about 2%); SAPO: 380 oC, 3mL/gcat/h, all catalysts were tested in a tubular fixed bed reactor, with catalyst 0.2 g. With reaction temperatures increasing, CO2 conversion is increased, but the lower olefins selectivity declines while CO selectivity grows (Figure 2b). This agrees well with the kinetic behavior of CO2 hydrogenation to

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methanol on ZnZrO (Figure S5) because higher temperature favour the reverse water gas shift reaction on most methanol synthesis catalysts. To achieve a high yield of lower olefins, the reaction conditions were optimized to be, temperature 380 oC, space velocity 3600 mL/gcat/h, where the single pass CO2 conversion 12.6%, and lower olefins selectivity above 80%. It should be point out that the selectivity of lower olefins can be further enhanced from 80% to 93% when the space velocity is increased from 3600 to 20000 mL/gcat/h, and the selectivity of C1 and C5+ are suppressed to marginal (Figure 2c). This performance is superior to that of the Fischer-Tropsch process of CO2 hydrogenation in terms of lower olefins selectivity59-60. It is noteworthy that the tandem catalyst shows good stability over 100 h on stream without obvious deactivation (Figure 2d), and it also shows high thermal stability and sulfur resistance property (Figure S6a) suggesting its potential application in industry.

To understand the working mechanism in the tandem catalyst, CO2 hydrogenation on ZnZrO and ZnZrO/SAPO was compared at the reaction temperatures for olefins formation. Surprisingly, we found that CO selectivity for the tandem catalyst can be significantly suppressed from >99% to 63% at 400 oC, and 98% to 47% at 380 oC comparing with that for ZnZrO alone (Figure. 3B). More interestingly, the methanol selectivity estimated from hydrocarbon selectivity (presumably the hydrocarbons are derived from methanol) is much higher for tandem catalyst than ZnZrO alone, indicating that the overall reaction, CO2 hydrogenation to lower olefins on tandem catalyst is not a simple sum of the two individual reactions (CO2 hydrogenation to methanol and methanol conversion to lower olefins), but a coupling reaction. The results in Figure 2a have already demonstrated that the SAPO component does not show evident conversion of CO or CO2 hydrogenation. Therefore, it is unambiguous to deduce that the methanol synthesis on ZnZrO is driven by the olefin formation reaction on SAPO during the CO2 hydrogenation to lower olefins on the tandem catalyst.

Figure 3. Tandem reaction coupling: a) Hydrogenation of CO2 over ZnZrO/SAPO, integrated catalyst components ZnZrO and SAPO with different proximity (380 oC, 2 MPa, 3600 mL/gcat/h); b) Hydrogenation of CO2 over ZnZrO and ZnZrO/SAPO at reaction temperatures 360400 oC (2 MPa, 3600 mL/gcat/h). To clarify the tandem catalysis over ZnZrO/SAPO, the catalytic performance of the tandem catalyst was compared with those of the two individual catalysts integrated in different proximity in a tubular fixed bed reactor (Figure 3a). When ZnZrO and SAPO are mixed in granule (200~450 μm), C2=-C4= selectivity is decreased sharply from 80% to 40%, while CO selectivity is increased from 43% to 62% (Figure 3a, II). Similar results are obtained when some quartz sand particulates (200~450 μm) are mixed with the two component particulates (Figure 3a, III). These facts prove that the changes in selectivity are mainly due to the spatial separation between ZnZrO and SAPO. To further investigate the effect of the catalyst separation distance on selectivity, the ZnZrO and SAPO particulates were separated in space with a quartz sand layer (Figure 3a, IV), the lower olefins selectivity severely deteriorates, and CO becomes the dominant product, alike the results for only the ZnZrO catalyst (Figure 3a, V). The fact that the lower olefins selectivity drops dramatically when the two catalyst components are located apart suggests that the excellent selectivity for the tandem catalyst is due to the effective synergy61 between the two catalyst components ZnZrO and SAPO which is intimately in contact with each other.

Figure 4. Reaction intermediate species: a) In-situ DRIFT spectra from CO2 hydrogenation over ZnZrO and

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ZnZrO/SAPO at different temperatures (0.1 MPa, 3600 mL/gcat/h)); b) Chemical trapping-mass spectrometry results with a trapping reagent CD3OD during the CO2 hydrogenation over ZnZrO at reaction temperatures 50400 oC (0.1 MPa, 3600 mL/gcat/h); c) the scheme of chemical trapping using CD3OD as trapping reagent during CO2 hydrogenation; d) Schematic for the proposed reaction mechanism of CO2 hydrogenation on the tandem catalyst, ZnZrO/SAPO. The interesting driving effect in the tandem reaction is further discussed in terms of thermodynamics and kinetics. The hydrogenation of CO2 is unfavorable in thermodynamics, but the conversion of methanol to lower olefins is considerably favorable, so an apparent coupling of these two reactions, hydrogenation of CO2 to lower olefins is favorable (Figure S10). However, this thermodynamic coupling is observed only when the two catalyst components are in proximate contact. To understand the coupling in reaction kinetics, the surface species formed on ZnZrO and the tandem catalyst were detected by an in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) (Figure 4a) and quantitatively analyzed using a chemical trapping-mass spectrometry method (Figure 4b and 4c). Under reaction conditions, mainly HCOO* (2980, 2880, and 2835 cm-1) and CH3O* (2930 and 2824 cm-1) species62 are distinctly observed for ZnZrO, but the IR intensities of CH3O* species become much weaker for the tandem catalyst, implying that the CH3O* species on ZnZrO are more likely to transfer onto SAPO for olefins production. It is interesting to note that the IR intensities of CH3O* species are quite weak and those of HCOO* are even invisible for ZnZrO/SAPO under the reaction conditions (Figure 4a), but the chemical trapping gives strong mass signals of CD3CHO and CH3OCD3 (derived from CHO* and CH3O* species respectively) (Figure 4b, 4c), suggesting that the CHO* and CH3O* species are more actively involved in the reactions (Figure 4b). These results could conclude that the CHxO species (mainly surface CH3O*, CHO* species and gas phase CH3OH) are derived first on the surface of ZnZrO and then possibly transfer onto SAPO zeolite where these species are converted to hydrocarbons. Based on the surface reaction kinetics, it is proposed that the tandem reaction proceeds as follows: 1) the generation of CHxO species via CO2 hydrogenation on ZnZrO; 2) the derived CHxO species migrate/transfer onto SAPO zeolite for lower olefins production (as shown in Figure 4d). In summary, the direct hydrogenation of CO2 to lower olefins with outstanding selectivity was realized by constructed tandem catalyst, ZnZrO/SAPO, which CO2 and H2 were activated on ZnZrO and the C-C bond formation was performed on SAPO. The selectivity of lower olefins can reach to 80% while only 3% methane among hydrocarbon products at a CO2 of 12.6%. Tandem catalysis facilitates the thermodynamics and kinetics coupling through the transferring and migrating of CHxO intermediate species that not only included methanol, which enable the high efficient conversion of CO2 to

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lower olefins. Tandem catalyst showed the resistance to thermal and sulfur treatments (H2S and SO2), suggesting the promising potential application in industry.

ASSOCIATED CONTENT Supporting Information. “This material is available free of charge via the Internet at http://pubs.acs.org.” Details on catalysts preparation, catalysts characterization data of catalysts evaluation.

AUTHOR INFORMATION Corresponding Author *E-mail: [email protected]

ORCID Zelong Li: 0000-0002-5322-5065 Can Li: 0000-0002-9301-7850

Notes The authors declare no competing financial interest.

ACKNOWLEDGMENT This work was supported by grants from DICP Fundamental Research Program for Clean Energy and Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB17020200), the National Natural Science Foundation of China (21703240) and General and Special Financial Grant from the China Postdoctoral Science Foundation (Grant No. 2015M580233 and 2016T90231). We thank J.L. for discussion of DRIFTS results and W.Y. for discussion of chemical trapping experiment.

REFERENCES (1) Sakakura, T.; Choi, J. C.; Yasuda, H., Chem. Rev. 2007, 107, 2365-2387. (2) Wang, W.; Wang, S.; Ma, X.; Gong, J., Chem. Soc. Rev. 2011, 40, 3703-3727. (3) Rodemerck, U.; Holena, M.; Wagner, E.; Smejkal, Q.; Barkschat, A.; Baerns, M., Chemcatchem 2013, 5, 1948-1955. (4) Porosoff, M. D.; Yan, B. H.; Chen, J. G. G., Energy Environ. Sci. 2016, 9, 62-73. (5) Dorner, R. W.; Hardy, D. R.; Williams, F. W.; Willauer, H. D., Energy Environ. Sci. 2010, 3, 884-890. (6) Aresta, M.; Dibenedetto, A.; Quaranta, E., J. Catal. 2016, 343, 2-45. (7) Robert, M., ACS Energy Lett. 2016, 1, 281-282. (8) Wang, X.; Yang, G.; Zhang, J.; Chen, S.; Wu, Y.; Zhang, Q.; Wang, J.; Han, Y.; Tan, Y., Chem. Commun. 2016, 52, 73527355. (9) Li, S.; Xu, Y.; Chen, Y.; Li, W.; Lin, L.; Li, M.; Deng, Y.; Wang, X.; Ge, B.; Yang, C.; Yao, S.; Xie, J.; Li, Y.; Liu, X.; Ma, D., Angew. Chem. Int. Ed. 2017, 56, 10761-10765. (10) Aresta, M.; Dibenedetto, A.; Angelini, A., J. CO2 Util. 2013, 34, 65-73. (11) Li, Y.; Yan, T.; Junge, K.; Beller, M., Angew. Chem, Int. Ed. 2014, 53, 10476-10480. (12) Liu, Q.; Wu, L.; Jackstell, R.; Beller, M., Nat. Commun. 2015, 6, 5933-5947. (13) Liu, X. H.; Ma, J. G.; Niu, Z.; Yang, G. M.; Cheng, P., Angew. Chem. Int. Ed. 2015, 54, 988-991. (14) Kato, S.; Matam, S. K.; Kerger, P.; Bernard, L.; Battaglia, C.; Vogel, D.; Rohwerder, M.; Zuttel, A., Angew. Chem. Int. Ed. 2016, 55, 6028-6032. (15) Seo, H.; Katcher, M. H.; Jamison, T. F., Nat. Chem. 2017, 9, 453-456.

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(16) Corma, A.; Melo, F. V.; Sauvanaud, L.; Ortega, F., Catal. Today 2005, 107-08, 699-706. (17) Diercks, R.; Arndt, J. D.; Freyer, S.; Geier, R.; Machhammer, O.; Schwartze, J.; Volland, M., Chem. Eng. Technol. 2008, 31, 631-637. (18) Centi, G.; Quadrelli, E. A.; Perathoner, S., Energy Environ. Sci. 2013, 6, 1711-1731. (19) Makio, H.; Fujita, T., Acc. Chem. Res. 2009, 42, 1532-1544. (20) Torres Galvis, H. M.; Bitter, J. H.; Khare, C. B.; Ruitenbeek, M.; Dugulan, A. I.; de Jong, K. P., Science 2012, 335, 835-838. (21) Torres Galvis, H. M.; de Jong, K. P., ACS Catal. 2013, 3, 21302149. (22) Lu, J.; Yang, L.; Xu, B.; Wu, Q.; Zhang, D.; Yuan, S.; Zhai, Y.; Wang, X.; Fan, Y.; Hu, Z., ACS Catal. 2014, 4, 613-621. (23) Cheng, K.; Gu, B.; Liu, X.; Kang, J.; Zhang, Q.; Wang, Y., Angew. Chem. Int. Ed. 2016, 55, 4725-4728. (24) Cheng, Y.; Lin, J.; Xu, K.; Wang, H.; Yao, X.; Pei, Y.; Yan, S.; Qiao, M.; Zong, B., ACS Catal. 2016, 6, 389-399. (25) de Jong, K. P., Science 2016, 351, 1030-1031. (26) Jiao, F.; Li, J.; Pan, X.; Xiao, J.; Li, H.; Ma, H.; Wei, M.; Pan, Y.; Zhou, Z.; Li, M.; Miao, S.; Li, J.; Zhu, Y.; Xiao, D.; He, T.; Yang, J.; Qi, F.; Fu, Q.; Bao, X., Science 2016, 351, 1065-1068. (27) Xie, J.; Torres Galvis, H. M.; Koeken, A. C.; Kirilin, A.; Dugulan, A. I.; Ruitenbeek, M.; de Jong, K. P., ACS Catal. 2016, 6, 4017-4024. (28) Zhong, L.; Yu, F.; An, Y.; Zhao, Y.; Sun, Y.; Li, Z.; Lin, T.; Lin, Y.; Qi, X.; Dai, Y.; Gu, L.; Hu, J.; Jin, S.; Shen, Q.; Wang, H., Nature 2016, 538, 84-87. (29) Zhu, Y.; Pan, X.; Jiao, F.; Li, J.; Yang, J.; Ding, M.; Han, Y.; Liu, Z.; Bao, X., ACS Catal. 2017, 7, 2800-2804. (30) Zhai, P.; Xu, C.; Gao, R.; Liu, X.; Li, M.; Li, W.; Fu, X.; Jia, C.; Xie, J.; Zhao, M.; Wang, X.; Li, Y. W.; Zhang, Q.; Wen, X. D.; Ma, D., Angew. Chem. Int. Ed. 2016, 55, 9902-9907. (31) Cheng, K.; Zhou, W.; Kang, J.; He, S.; Shi, S.; Zhang, Q.; Pan, Y.; Wen, W.; Wang, Y., Chem 2017, 3, 334-347. (32) Zhao, B.; Zhai, P.; Wang, P.; Li, J.; Li, T.; Peng, M.; Zhao, M.; Hu, G.; Yang, Y.; Li, Y.-W.; Zhang, Q.; Fan, W.; Ma, D., Chem 2017, 3, 323-333. (33) Behrens, M.; Studt, F.; Kasatkin, I.; Kuhl, S.; Havecker, M.; Abild-Pedersen, F.; Zander, S.; Girgsdies, F.; Kurr, P.; Kniep, B. L.; Tovar, M.; Fischer, R. W.; Norskov, J. K.; Schlogl, R., Science 2012, 336, 893-897. (34) Graciani, J.; Mudiyanselage, K.; Xu, F.; Baber, A. E.; Evans, J.; Senanayake, S. D.; Stacchiola, D. J.; Liu, P.; Hrbek, J.; Fernandez Sanz, J.; Rodriguez, J. A., Science 2014, 345, 546-550. (35) Kuld, S.; Thorhauge, M.; Falsig, H.; Elkjaer, C. F.; Helveg, S.; Chorkendorff, I.; Sehested, J., Science 2016, 352, 969-974. (36) Rungtaweevoranit, B.; Baek, J.; Araujo, J. R.; Archanjo, B. S.; Choi, K. M.; Yaghi, O. M.; Somorjai, G. A., Nano Lett. 2016, 16, 7645-7649. (37) An, B.; Zhang, J.; Cheng, K.; Ji, P.; Wang, C.; Lin, W., J. Am. Chem. Soc. 2017, 139, 3834-3840. (38) Kattel, S.; Ramirez, P. J.; Chen, J. G.; Rodriguez, J. A.; Liu, P., Science 2017, 355, 1296-1299. (39) Larmier, K.; Liao, W. C.; Tada, S.; Lam, E.; Verel, R.; Bansode, A.; Urakawa, A.; Comas-Vives, A.; Coperet, C., Angew. Chem. Int. Ed. 2017, 56, 2318-2323.

(40) Studt, F.; Sharafutdinov, I.; Abild-Pedersen, F.; Elkjaer, C. F.; Hummelshoj, J. S.; Dahl, S.; Chorkendorff, I.; Norskov, J. K., Nat. Chem. 2014, 6, 320-324. (41) Fiordaliso, E. M.; Sharafutdinov, I.; Carvalho, H. W. P.; Grunwaldt, J. D.; Hansen, T. W.; Chorkendorff, I.; Wagner, J. B.; Damsgaard, C. D., ACS Catal. 2015, 5, 5827-5836. (42) Yang, X.; Kattel, S.; Senanayake, S. D.; Boscoboinik, J. A.; Nie, X.; Graciani, J.; Rodriguez, J. A.; Liu, P.; Stacchiola, D. J.; Chen, J. G., J. Am. Chem. Soc. 2015, 137, 10104-10107. (43) Kattel, S.; Yu, W.; Yang, X.; Yan, B.; Huang, Y.; Wan, W.; Liu, P.; Chen, J. G., Angew. Chem. Int. Ed. 2016, 55, 79687973. (44) Khan, M. U.; Wang, L.; Liu, Z.; Gao, Z.; Wang, S.; Li, H.; Zhang, W.; Wang, M.; Wang, Z.; Ma, C.; Zeng, J., Angew. Chem. Int. Ed. 2016, 55, 9548-9552. (45) Garcia-Trenco, A.; White, E. R.; Regoutz, A.; Payne, D. J.; Shaffer, M. S. P.; Williams, C. K., ACS Catal. 2017, 7, 11861196. (46) Li, C. S.; Melaet, G.; Ralston, W. T.; An, K.; Brooks, C.; Ye, Y.; Liu, Y. S.; Zhu, J.; Guo, J.; Alayoglu, S.; Somorjai, G. A., Nat. Commun. 2015, 6, 6538-6542. (47) Sun, K. H.; Fan, Z. G.; Ye, J. Y.; Yan, J. M.; Ge, Q. F.; Li, Y. N.; He, W. J.; Yang, W. M.; Liu, C. J., J. CO2 Util. 2015, 12, 1-6. (48) Martin, O.; Martin, A. J.; Mondelli, C.; Mitchell, S.; Segawa, T. F.; Hauert, R.; Drouilly, C.; Curulla-Ferre, D.; PerezRamirez, J., Angew. Chem. Int. Ed. 2016, 55, 6261-6265. (49) Olsbye, U.; Svelle, S.; Bjorgen, M.; Beato, P.; Janssens, T. V.; Joensen, F.; Bordiga, S.; Lillerud, K. P., Angew. Chem. Int. Ed. 2012, 51, 5810-5831. (50) Liang, T.; Chen, J.; Qin, Z.; Li, J.; Wang, P.; Wang, S.; Wang, G.; Dong, M.; Fan, W.; Wang, J., ACS Catal. 2016, 6, 73117325. (51) Dai, W.; Wang, C.; Dyballa, M.; Wu, G.; Guan, N.; Li, L.; Xie, Z.; Hunger, M., ACS Catal. 2015, 5, 317-326. (52) Tian, P.; Wei, Y.; Ye, M.; Liu, Z., ACS Catal. 2015, 5, 19221938. (53) Wang, Y.; Chen, S.-L.; Gao, Y.-L.; Cao, Y.-Q.; Zhang, Q.; Chang, W.-K.; Benziger, J. B., ACS Catal. 2017, 7, 5572-5584. (54) Fujiwara, M.; Souma, Y., J. Chem. Soc. Chem. Commun. 1992, 767-768. (55) Park, Y. K.; Park, K. C.; Ihm, S. K., Catal. Today 1998, 44, 165-173. (56) Wei, J.; Ge, Q.; Yao, R.; Wen, Z.; Fang, C.; Guo, L.; Xu, H.; Sun, J., Nat. Commun. 2017, 8, 15174-15181. (57) Gao, P.; Li, S.; Bu, X.; Dang, S.; Liu, Z.; Wang, H.; Zhong, L.; Qiu, M.; Yang, C.; Cai, J.; Wei, W.; Sun, Y., Nat. Chem. 2017, 9, 1019-1024. (58) Xie, C.; Chen, C.; Yu, Y.; Su, J.; Li, Y.; Somorjai, G. A.; Yang, P., Nano Lett. 2017, 17, 3798-3802. (59) Satthawong, R.; Koizumi, N.; Song, C.; Prasassarakich, P., Catal. Today 2015, 251, 34-40. (60) Gnanamani, M. K.; Jacobs, G.; Hamdeh, H. H.; Shafer, W. D.; Liu, F.; Hopps, S. D.; Thomas, G. A.; Davis, B. H., ACS Catal. 2016, 6, 913-927. (61) Zecevic, J.; Vanbutsele, G.; de Jong, K. P.; Martens, J. A., Nature 2015, 528, 245-248. (62) Kattel, S.; Yan, B.; Yang, Y.; Chen, J. G.; Liu, P., J. Am. Chem. Soc. 2016, 138, 12440-12450.

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