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Photo-Chemically-Deposited and Industrial Cu/ZnO/Al2O3 Catalyst Material Surface Structures During CO2 Hydrogenation to Methanol: EXAFS, XANES and XPS Analyses of Phases After Oxidation, Reduction, and Reaction

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Abstract

Industrial Cu/ZnO/Al2O3 or novel rate catalysts, prepared with a photochemical deposition method, were studied under functional CH3OH synthesis conditions at the set temperature (T) range of 240–350 °C, 20 bar pressure, and stoichiometric carbon dioxide/hydrogen composition. Analytical scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray adsorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) methods were systematically utilized to investigate the interfaces, measured local geometry, and chemical state electronics around the structured active sites of commercially available Cu/ZnO/Al2O3 material or synthesized Cu/ZnO. Processed Cu K-edge EXAFS analysis suggested that various Cu atom species, clusters, metallic fcc Cu, Cu oxides (Cu2O or CuO) and the Cu0.7Zn2 alloy with hexagonal crystalline particles are contained after testing. It was proposed that in addition to the model’s Cu surface area, the amount, ratio and dispersion of the mentioned bonded Cu compounds significantly influenced activity. Additionally, XPS revealed that carbon may be deposited on the commercial Cu/ZnO/Al2O3, forming the inactive carbide coating with Cu or/and Zn, which may be the cause of basicity’s severe deactivation during reactions. The selectivity to methanol decreased with increasing T, whereas more Cu0.7Zn2 inhibited the CO formation through reverse water–gas shift (RWGS) CO2 reduction.

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References

  1. Chen LF, Guo PJ, Qiao MH, Yan SR, Li HX, Shen W, Xu HL, Fan KN (2008) Cu/ SiO2 catalysts prepared by the ammonia-evaporation method: texture, structure, and catalytic performance in hydrogenation of dimethyl oxalate to ethylene glycol. J Catal 257:172–180. https://doi.org/10.1016/j.jcat.2008.04.021

    Article  CAS  Google Scholar 

  2. Velu S, Suzuki K, Gopinath CS, Yoshida H, Hattori T (2002) XPS, XANES and EXAFS investigations of CuO/ZnO/Al2O3/ZrO2 mixed oxide catalysts. Phys Chem Chem Phys 4:1990–1999. https://doi.org/10.1039/B109766K

    Article  CAS  Google Scholar 

  3. Tanaka Y, Utaka T, Kikuchi R, Sasaki K, Eguchi K (2003) Water gas shift reaction over Cu-based mixed oxides for CO removal from the reformed fuels. Appl Catal A 242:287–295. https://doi.org/10.1016/S0926-860X(02)00529-X

    Article  CAS  Google Scholar 

  4. Olah GA, Goeppert A, Prakash GKS (2009) Chemical recycling of carbon dioxide to methanol and dimethyl ether: from greenhouse gas to renewable, environmentally carbon neutral fuels and synthetic hydrocarbons. J Org Chem 74:487–498. https://doi.org/10.1021/jo801260f

    Article  PubMed  CAS  Google Scholar 

  5. Laudenschleger D, Ruland H, Muhler M (2020) Identifying the nature of the active sites in methanol synthesis over Cu/ZnO/Al2O3 catalysts. Nat Commun 11(1):3898. https://doi.org/10.1038/s41467-020-17631-5

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  6. Ye R-P, Ding J, Gong W, Argyle MD, Zhong Q, Wang Y, Russell CK, Xu Z, Russell AG, Li Q, Fan M, Yao Y-G (2019) CO2 hydrogenation to high-value products via heterogeneous catalysis. Nat Commun 10(1):5698. https://doi.org/10.1038/s41467-019-13638-9

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  7. Kuld S, Thorhauge M, Falsig H, Elkjaer CF, Helveg S, Chorkendorff I, Sehested J (2016) Quantifying the promotion of Cu catalysts by ZnO for methanol synthesis. Science 352(6288):969–974. https://doi.org/10.1126/science.aaf0718

    Article  PubMed  CAS  Google Scholar 

  8. Le Valant A, Comminges C, Tisseraud C, Canaff C, Pinard L, Pouilloux Y (2015) The Cu–ZnO synergy in methanol synthesis from CO2, part 1: origin of active site explained by experimental studies and a sphere contact quantification model on Cu plus ZnO mechanical mixtures. J Catal 324:41–49. https://doi.org/10.1016/j.jcat.2015.01.021

    Article  CAS  Google Scholar 

  9. Tauster SJ, Fung SC, Baker RTK, Horsley JA (1981) Strong interactions in supported-metal catalysts. Science 211(4487):1121–1125. https://doi.org/10.1126/science.211.4487.1121

    Article  PubMed  CAS  Google Scholar 

  10. Kuld S, Conradsen C, Moses PG, Chorkendorff I, Sehested J (2014) Quantification of zinc atoms in a surface alloy on copper in an industrial-type methanol synthesis catalyst. Angew Chem Int Ed Engl 53:5941–5945. https://doi.org/10.1002/anie.201311073

    Article  PubMed  CAS  Google Scholar 

  11. Kuld S, Thorhauge M, Falsig H, Elkjær CF, Helveg S, Chorkendorff I (2016) Quantifying the promotion of Cu catalysts by ZnO for methanol synthesis. Science 352(6288):969–974. https://doi.org/10.1126/science.aaf0718

    Article  PubMed  CAS  Google Scholar 

  12. Kirkendall E, Thomassen L, Upthegrove C (1939) Rates of diffusion of copper and zinc in alpha brass. Trans AIME 133:186–203

    Google Scholar 

  13. Behrens M, Lolli G, Muratova N, Kasatkin I, Hävecker M, d’Alnoncourt RN, Storcheva O, Köhler K, Muhler M, Schlögl R (2013) The effect of Al-doping on ZnO nanoparticles applied as catalyst support. Phys Chem Chem Phys 15:1374–1381. https://doi.org/10.1039/C2CP41680H

    Article  PubMed  CAS  Google Scholar 

  14. Kasatkin I, Kurr P, Kniep B, Trunschke A, Schlögl R (2007) Role of lattice strain and defects in copper particles on the activity of Cu/ZnO/Al2O3 catalysts for methanol synthesis. Angew Chem Int Ed Engl 46:7324–7327. https://doi.org/10.1002/anie.200702600

    Article  PubMed  CAS  Google Scholar 

  15. Behrens M, Studt F, Kasatkin I, Kühl S, Hävecker M, Abild-Pedersen F, Zander S, Girgsdies F, Kurr P, Kniep BL, Tovar M, Fischer RW, Nørskov JK, Schlögl R (2012) The active site of methanol synthesis over Cu/ZnO/Al2O3 industrial catalysts. Science 336(6083):893–898. https://doi.org/10.1126/science.1219831

    Article  PubMed  CAS  Google Scholar 

  16. Fichtl MB, Schlereth D, Jacobsen N, Kasatkin I, Schumann J, Behrens M, Schlögl R, Hinrichsen O (2015) Kinetics of deactivation on Cu/ZnO/Al2O3 methanol synthesis catalysts. Appl Catal A 502:262–270. https://doi.org/10.1016/j.apcata.2015.06.014

    Article  CAS  Google Scholar 

  17. Forzatti P, Lietti L (1999) Catalyst deactivation. Catal Today 52:165–181. https://doi.org/10.1016/S0920-5861(99)00074-7

    Article  CAS  Google Scholar 

  18. Hansen JB, Nielsen PEH (2008) Methanol synthesis. In: Ertl G, Knözinger H, Schüth F, Weitkamp J (eds) Handbook of heterogeneous catalysis, 2nd edn. Wiley, Weinheim, pp 2920–2949

    Google Scholar 

  19. Fujitani T, Nakamura I, Uchijima T, Nakamura J (1997) The kinetics and mechanism of methanol synthesis by hydrogenation of CO2 over a Zn-deposited Cu(111) surface. Surf Sci 383:285–298. https://doi.org/10.1016/S0039-6028(97)00192-1

    Article  CAS  Google Scholar 

  20. Samei E, Taghizadeh M, Bahmani M (2012) Enhancement of stability and activity of Cu/ZnO/Al2O3 catalysts by colloidal silica and metal oxides additives for methanol synthesis from a CO2-rich feed. Fuel Process Technol 96:128–133. https://doi.org/10.1016/j.fuproc.2011.12.028

    Article  CAS  Google Scholar 

  21. Bitenc M, Marinšek M, Crnjak Orel Z (2008) Preparation and characterization of zinc hydroxide carbonate and porous zinc oxide particles. J Eur Ceram Soc 28:2915–2921. https://doi.org/10.1016/j.jeurceramsoc.2008.05.003

    Article  CAS  Google Scholar 

  22. Dasireddy VDBC, Likozar B (2019) The role of copper oxidation state in Cu/ZnO/Al2O3 catalysts in CO2 hydrogenation and methanol productivity. Renew Energy 140:452–460. https://doi.org/10.1016/j.renene.2019.03.073

    Article  CAS  Google Scholar 

  23. Dasireddy VDBC, Likozar B, Valand J (2018) Preferential oxidation of CO in H2/H2O/CO2 water–gas shift feedstocks over Cu-based carbon nanotubes-supported heterogeneous catalysts. Appl Catal B 237:1044–1058. https://doi.org/10.1016/j.apcatb.2018.06.069

    Article  CAS  Google Scholar 

  24. Ravel B, Newville M (2005) ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT. J Synchrotron Rad 12:537–541. https://doi.org/10.1107/S0909049505012719

    Article  CAS  Google Scholar 

  25. Rehr JJ, Albers RC, Zabinsky SI (1992) High-order multiple-scattering calculations of X-ray-absorption fine structure. Phys Rev Lett 69:3397–3400. https://doi.org/10.1103/PhysRevLett.69.3397

    Article  PubMed  CAS  Google Scholar 

  26. Günter MM, Ressler T, Bems B, Büscher C, Genger T, Hinrichsen O, Muhler M, Schlögl R (2001) Implication of the microstructure of binary Cu/ZnO catalysts for their catalytic activity in methanol synthesis. Catal Lett 71:37–44. https://doi.org/10.1023/A:1016696022840

    Article  Google Scholar 

  27. Fujitani T, Nakamura J (1998) The effect of ZnO in methanol synthesis catalysts on Cu dispersion and the specific activity. Catal Lett 56:119–124. https://doi.org/10.1023/A:1019000927366

    Article  CAS  Google Scholar 

  28. Rao SS, Anantharaman TR (1963) Accurate evaluation of lattice parameters of α-brasses. Curr Sci 32:262–263

    CAS  Google Scholar 

  29. Natesakhawat S, Lekse JW, Baltrus JP, Ohodnicki PR, Howard BH, Deng X, Matranga C (2012) Active sites and structure–activity relationships of copper-based catalysts for carbon dioxide hydrogenation to methanol. ACS Catal 2:1667–1676. https://doi.org/10.1021/cs300008g

    Article  CAS  Google Scholar 

  30. Choi Y, Futagami K, Fujitani T, Nakamura J (2001) The role of ZnO in Cu/ZnO methanol synthesis catalysts-morphology effect or active site model. Appl Catal A 208:163–167. https://doi.org/10.1016/S0926-860X(00)00712-2

    Article  CAS  Google Scholar 

  31. Harikumar KR, Rao CNR (1998) Interaction of CO with catalyst surfaces prepared in situ in the electron spectrometer: evidence for CO2 and related species relevant to methanol synthesis. Appl Surf Sci 125:245–249. https://doi.org/10.1016/S0169-4332(97)00589-8

    Article  CAS  Google Scholar 

  32. Lee C, Lee H, Yen Y, Kuo Y (2005) Reaction mechanism of the two-step MOCVD of copper thin film using Cu(hfac)2 H2O source. Electrochem Solid-State Lett 8:G307–G310. https://doi.org/10.1149/1.2052050

    Article  CAS  Google Scholar 

  33. Agarwal V, Patel S, Pant KK (2005) H2 production by steam reforming of methanol over Cu/ZnO/Al2O3 catalysts: transient deactivation kinetics modeling. Appl Catal A 279:155–164. https://doi.org/10.1016/j.apcata.2004.10.026

    Article  CAS  Google Scholar 

  34. Sacco A, Porro S, Lamberti A, Gerosa M, Castellino M, Chiodoni A, Bianco S (2014) Investigation of transport and recombination properties in graphene/titanium dioxide nanocomposite for dye-sensitized solar cell photoanodes. Electrochim Acta 131:154–159. https://doi.org/10.1016/j.electacta.2013.11.105

    Article  CAS  Google Scholar 

  35. Dasireddy VDBC, Strah Štefančič N, Huš M, Likozar B (2018) Effect of alkaline earth metal oxide (MO) Cu/MO/Al2O3 catalysts on methanol synthesis activity and selectivity via CO2 reduction. Fuel 233:103–112. https://doi.org/10.1016/j.fuel.2018.06.046

    Article  CAS  Google Scholar 

  36. Pori M, Likozar B, Marinšek M, Crnjak Z (2016) Orel, Preparation of Cu/ZnO-based heterogeneous catalysts by photochemical deposition, their characterisation and application for methanol synthesis from carbon dioxide and hydrogen. Fuel Process Technol 146:39–47. https://doi.org/10.1016/j.fuproc.2016.02.021

    Article  CAS  Google Scholar 

  37. Lytle FW, Greegor RB, Panson AJ (1988) Discussion of X-ray absorption near edge structure: application to Cu in high Tc superconductors La1.8Sr0.2CuO4 and YBa2Cu307. Phys Rev B 37:1550–1562. https://doi.org/10.1103/PhysRevB.37.1550

    Article  CAS  Google Scholar 

  38. Manceau A, Matynia A (2010) The nature of Cu bonding to natural organic matter. Geochim Cosmochim Acta 74:2556–2580. https://doi.org/10.1016/j.gca.2010.01.027

    Article  CAS  Google Scholar 

  39. Castagnola NB, Kropf AJ, Marshall CL (2005) Studies of Cu-ZSM-5 by X-ray absorption spectroscopy and its application for the oxidation of benzene to phenol by air. Appl Catal A 290:110–122. https://doi.org/10.1016/j.apcata.2005.05.022

    Article  CAS  Google Scholar 

  40. Arčon I, Kolar J, Kodre A, Hanžel D, Strlič M (2007) XANES analysis of Fe valence in iron gall inks. X-Ray Spectrom 36:199–205. https://doi.org/10.1002/xrs.962

    Article  CAS  Google Scholar 

  41. Čižmar T, Lavrenčič Štangar U, Fanetti M, Arcon I (2018) Effects of different Cu loadings on photocatalytic activity of TiO2-SiO2 prepared at low temperature for the oxidation of organic pollutants in water. ChemCatChem 10:2982–2993. https://doi.org/10.1002/cctc.201801076

    Article  Google Scholar 

  42. Teržan J, Djinović P, Zavašnik J, Arčon I, Žerjav G, Spreitzer M, Pintar A (2018) Alkali and earth alkali modified CuOx/SiO2 catalysts for propylene partial oxidation: What determines the selectivity? Appl Catal B 237:214–227. https://doi.org/10.1016/j.apcatb.2018.05.092

    Article  CAS  Google Scholar 

  43. Alayon EMC, Nachtegaal M, Bodi A, Ranocchiari M, van Bokhoven JA (2015) Bis(m-oxo) versus mono(m-oxo)dicopper cores in a zeolite for converting methane to methanol: an in situ XAS and DFT investigation. Phys Chem Chem Phys 17:7681–7693. https://doi.org/10.1039/C4CP03226H

    Article  PubMed  CAS  Google Scholar 

  44. Lenz J, Schubert K (1971) Über einige Leerstellen- und Stapelvarianten der Beta-Messing Strukturfamilie. Zeitschrift für Matallkunde 62:810–816

    CAS  Google Scholar 

  45. Schmahl NG, Eikerling GF (1968) Über Kryptomodifikationen des Cu(II)-Oxids. Zeitschrift für Physikalische Chemie 62:268–279. https://doi.org/10.1524/zpch.1968.62.5_6.268

    Article  CAS  Google Scholar 

  46. Pori M, Arčon I, Lašič Jurković D, Marinšek M, Dražić G, Likozar B, Crnjak Orel Z (2019) Synthesis of a Cu/ZnO Nanocomposite by electroless plating for the catalytic conversion of CO2 to methanol. Catal Lett 149:1427–1439. https://doi.org/10.1007/s10562-019-02717-7

    Article  CAS  Google Scholar 

  47. Arčon I, Tuel A, Kodre A, Martin G, Barbier A (2001) EXAFS determination of the size of Co clusters on silica. J Synchrotron Rad 8:575–577. https://doi.org/10.1107/S0909049500019294

    Article  Google Scholar 

  48. Arena F, Barbera K, Italiano G, Bonura G, Spadaro L, Frusteri F (2007) Synthesis, characterization and activity pattern of Cu–ZnO/ZrO2 catalysts in the hydrogenation of carbon dioxide to methanol. J Catal 249:185–194. https://doi.org/10.1016/j.jcat.2007.04.003

    Article  CAS  Google Scholar 

  49. Jones SD, Neal LM, Hagelin-Weaver HE (2008) Steam reforming of methanol using Cu-ZnO catalysts supported on nanoparticle alumina. Appl Catal B 84:631–642. https://doi.org/10.1016/j.apcatb.2008.05.023

    Article  CAS  Google Scholar 

  50. Moretti G, Fierro G, Jacono Lo M, Porta P (1989) Characterization of CuO-ZnO catalysts by X-ray photoelectron spectroscopy: precursors, calcined and reduced samples. Surf Interface Anal 14:325–336. https://doi.org/10.1002/sia.740140609

    Article  Google Scholar 

  51. Tisseraud C, Comminges C, Pronier S, Pouilloux Y, Le Valant A (2016) The Cu–ZnO synergy in methanol synthesis part 3: impact of the composition of a selective Cu@ZnOx core–shell catalyst on methanol rate explained by experimental studies and a concentric spheres model. J Catal 343:106–114. https://doi.org/10.1016/j.jcat.2015.12.005

    Article  CAS  Google Scholar 

  52. Tisseraud C, Comminges C, Belin T, Ahouari H, Soualah A, Pouilloux Y, Le Valant A (2015) The Cu–ZnO synergy in methanol synthesis from CO2, part 2: origin of the methanol and CO selectivities explained by experimental studies and a sphere contact quantification model in randomly packed binary mixtures on Cu–ZnO coprecipitate catalysts. J Catal 330:533–544. https://doi.org/10.1016/j.jcat.2015.04.035

    Article  CAS  Google Scholar 

  53. Burch R, Chappell RJ, Golunski SE (1989) Synergy between copper and zinc oxide during methanol synthesis. Transfer of activating species. J. Chem. Soc Faraday Trans. 85:3569–3578. https://doi.org/10.1039/F19898503569

    Article  CAS  Google Scholar 

  54. Conner WC, Falconer JL (1995) Spillover in heterogeneous catalysis. Chem Rev 85:759–788. https://doi.org/10.1021/cr00035a014

    Article  Google Scholar 

  55. Grunwaldt JD, Molenbroek AM, Topsøe NY, Topsøe H, Clausen BS (2000) In situ investigations of structural changes in Cu/ZnO catalysts. J Catal 194:452–460. https://doi.org/10.1006/jcat.2000.2930

    Article  CAS  Google Scholar 

  56. Topsøe N, Topsøe H (1999) On the nature of surface structural changes in Cu/ZnO methanol synthesis catalysts. Top Catal 8:267–270. https://doi.org/10.1023/A:1019133832569

    Article  Google Scholar 

  57. Holse C, Elkjaer CF, Nierhoff A, Sehested J, Chorkendorff I, Helveg S, Nielsen JH (2015) Dynamic Behavior of CuZn nanoparticles under oxidizing and reducing conditions. J Phys Chem C 119:2804–2812. https://doi.org/10.1021/jp510015v

    Article  CAS  Google Scholar 

  58. Sankar G, Vasudevan S, Rao CNR (1986) An EXAFS investigation of Cu–ZnO methanol synthesis catalysts. J Chem Phys 85:2291–2299. https://doi.org/10.1063/1.451126

    Article  CAS  Google Scholar 

  59. Klier K, Chatikavanij V, Herman RG, Simmons GW (1982) Catalytic synthesis of methanol from: IV. The effects of carbon dioxide. J Catal 74:343–360. https://doi.org/10.1016/0021-9517(82)90040-9

    Article  CAS  Google Scholar 

  60. Grandjean D, Castricum HL, Van den Heuvel JC, Weckhuysen BM (2006) Highly mixed phases in ball-milled Cu/ZnO catalysts: an EXAFS and XANES study. J Phys Chem B 110:16892–16901. https://doi.org/10.1021/jp055820i

    Article  PubMed  CAS  Google Scholar 

  61. Chinchen GC, Waugh KC, Whan DA (1986) The activity and state of the copper surface in methanol synthesis catalysts. Appl Catal 25:101–107. https://doi.org/10.1016/S0166-9834(00)81226-9

    Article  CAS  Google Scholar 

  62. Fujitani T, Saito M, Kanai Y, Kakumoto T, Watanabe T, Nakamura J, Uchijima T (1994) The role of metal oxides in promoting a copper catalyst for methanol synthesis. Catal Lett 25:271–276. https://doi.org/10.1007/BF00816307

    Article  CAS  Google Scholar 

  63. Saito M, Fujitani T, Takeuchi M, Watanabe T (1996) Development of copper/zinc oxide-based multicomponent catalysts for methanol synthesis from carbon dioxide and hydrogen. Appl Catal A 138:311–318. https://doi.org/10.1016/0926-860X(95)00305-3

    Article  CAS  Google Scholar 

  64. Dasireddy VDBC, Neja SŠ, Likozar B (2018) Correlation between synthesis pH, structure and Cu/MgO/Al2O3 heterogeneous catalyst activity and selectivity in CO2 hydrogenation to methanol. J CO2 Util 28:189–199. https://doi.org/10.1016/j.jcou.2018.09.002

    Article  CAS  Google Scholar 

  65. Nielsen DU, Hu X-M, Daasbjerg K, Skrydstrup T (2018) Chemically and electrochemically catalysed conversion of CO2 to CO with follow-up utilization to value-added chemicals. Nat Catal 1(4):244–254. https://doi.org/10.1038/s41929-018-0051-3

    Article  CAS  Google Scholar 

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Acknowledgements

This work was supported by the Slovenian Research Agency (P1-0112, P1-0175, P2-152) and by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. XAS spectra measured at beamline P64 of PETRA III at DESY, Hamburg, a member of the Helmholtz Association (HGF) under project I-20160764 EC. We would like to thank Wolfgang Caliebe and Vadim Murzin for the expert advice on the beamline operation during the experiments.

Funding

The funding was provided by Horizon 2020 Framework Programme (Grant No. 730872) and Javna Agencija za Raziskovalno Dejavnost RS (Grant Nos. P1-0112, P1-0175, P2-152).

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Appendix

Appendix

See Figs. (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21) and Tables (4, 5, 6, 7, 8, 9).

Fig. 10
figure 10

High-temperature in-situ diffractograms of commercial catalyst CuO/ZnO/Al2O3 during the reduction. Commercial catalyst sample was scanned from 20° to 90°; the 1st scan was taken before reduction (20 °C), whereas thereafter, atmosphere was changed to H2/N2 (5 mol. %), increasing the temperature with 10 K min-1—after reaching 300 °C measurements were performed continuously (patterns 1–14)

Fig. 11
figure 11

HRTEM image of a Cu grain with and oxidative surface layer

Fig. 12
figure 12

Cu L3M4,5M4,5 auger transition spectras of the commercial Cu/ZnO/Al2O3 catalyst after reduction as well as after CH3OH synthesis

Fig. 13
figure 13

Deconvolution of C1s XPS peaks of the reduced Cu/ZnO/Al2O3 catalysts

Fig. 14
figure 14

XPS spectra of Cu/Al2O3 catalyst; a deconvolution of Cu 2p peaks, b deconvolution of O 1s peaks, c deconvolution of Al 2s peaks

Fig. 15
figure 15

XPS spectra of Cu/ZnO; a deconvolution of Cu 2p peaks, b deconvolution of Zn 2p peaks, c deconvolution of O 1s peaks

Fig. 16
figure 16

Cu K-edge XANES measured on catalyst A (dots: experiment; dashed line: best fit obtained with linear combination of XANES profiles of Cu fcc metal foil (31%) as references for metallic Cu, crystaline Cu2O (26%) as referemce for monovalent Cu, and crystalline CuO (43%) as reference for divalent Cu oxide. Fit components are plotted below)

Fig. 17
figure 17

Cu K-edge XANES measured on catalyst B (dots: experiment; dashed line: best fit obtained with linear combination of XANES profiles of Cu fcc metal nanoparticles (69%) and Cu fcc metal foil (22%) as references for metallic Cu, crystaline Cu2O (6%) as referemce for monovalent Cu, and crystalline CuO (3%) as reference for divalent Cu oxide. Fit components are shown below)

Fig. 18
figure 18

Cu K-edge XANES measured on the commercial Cu/ZnO/Al2O3 calcined catalyst (dots: experiment; dashed line: best fit obtained with linear combination of XANES profiles of crystalline CuO (23%) and CuO calcined (59%) as reference for divalent Cu oxide, and crystaline Cu2O (18%) as referemce for monovalent Cu. Fit components are shown below)

Fig. 19
figure 19

Cu K-edge XANES measured on the commercial Cu/ZnO/Al2O3 catalyst after reduction (dots: experiment; dashed line: best fit obtained with linear combination of XANES profiles of Cu fcc metal nanoparticles (30%) and Cu fcc metal foil (32%) as references for metallic Cu, crystaline Cu2O (20%) as referemce for monovalent Cu, and crystalline CuO (18%) as reference for divalent Cu oxide. Fit components are shown below)

Fig. 20
figure 20

Cu K-edge XANES measured on the commercial Cu/ZnO/Al2O3 catalyst after reaction (dots: experiment; dashed line: best fit obtained with linear combination of XANES profiles of Cu fcc metal nanoparticles (78%) as reference for metallic Cu, crystaline Cu2O (18%) as referemce for monovalent Cu, and crystalline CuO (4%) as reference for divalent Cu oxide. Fit components are shown below)

Fig. 21
figure 21

SEM micrographs of used catalyst A (left) and catalyst B (right)

Table 4 Calculated parameters of the nearest coordination shells around Cu atoms present in the calcined CuO/ZnO/Al2O3 catalyst: average number of neighbours (N), distance (d) and Debye–Waller factor (DWF); uncertainty of the last digit is given in parentheses; the best fit is obtained with amplitude reduction factor (S02) of 0.90 and shift of energy origin of photoelectron, ΔEo of 3.2(7) eV
Table 5 Calculated parameters of the nearest coordination shells around Cu atoms in each of the three Cu EXAFS models, describing Cu compounds (Cu metal, Cu0.7Zn2 alloy and Cu oxide), present in Cu/ZnO/Al2O3 catalyst after reduction
Table 6 Calculated parameters of the nearest coordination shells around Cu atoms in each of the three Cu EXAFS models, describing Cu compounds (Cu metal, Cu0.7Zn2 alloy and Cu oxide), present in Cu/ZnO/Al2O3 catalyst after reaction
Table 7 Calculated parameters of the nearest coordination shells around Cu atoms in each of the three Cu EXAFS models, describing Cu compounds (Cu metal, Cu0.7Zn2 alloy and Cu oxide), present in catalyst A
Table 8 Calculated parameters of the nearest coordination shells around Cu atoms in each of the three Cu EXAFS models, describing Cu compounds (Cu metal, Cu0.7Zn2 alloy and Cu oxide) present in catalyst B
Table 9 CO2 hydrogenation profile over the prepared catalysts

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Pori, M., Arčon, I., Dasireddy, V.D.B.C. et al. Photo-Chemically-Deposited and Industrial Cu/ZnO/Al2O3 Catalyst Material Surface Structures During CO2 Hydrogenation to Methanol: EXAFS, XANES and XPS Analyses of Phases After Oxidation, Reduction, and Reaction. Catal Lett 151, 3114–3134 (2021). https://doi.org/10.1007/s10562-021-03556-1

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