STM 3

Hydrogen storage with titanium-functionalized graphene

Hydrogen is well known as a possible clean fuel for the future since the only waste product is water. Nevertheless, one of the main problems dealing with hydrogen as a widespread energy carrier is its storage. In this respect, graphene has recently attracted attention as a promising medium due to its small weight, chemical stability, and attractive physico-chemical properties for hydrogen adsorption. The storage capacity can be further increased by chemical functionalization of the surface with different types of metals. One of the most promising materials for these studies is titanium. Calculations show that each adsorbed titanium atom can bind up to 4 to 5 H2 molecules, with related gravimetric density of 7.8 wt%. We study the deposition of titanium on graphene and its potential for hydrogen storage.

For this study we used epitaxial monolayer graphene grown on SiC(0001). Different quantities of titanium were deposited on this surface. The characteristics of the growth process and the amount of coverage were determined by scanning tunneling microscopy (STM) in ultra high vacuum (UHV). As shown in Fig. 1a, the titanium atoms form small islands (diameter ~ 10 nm) with a size distribution given in the inset.

Ti-STMFig 1: a) 100 x 100 nm2 UHV-STM image of a graphene surface with a titanium coverage of 16% (V = 2 V, I = 280 pA). The titanium atoms form small islands with a size distribution as shown in the inset. b) Desorption spectra measured for different coverages of titanium. The amount of stored hydrogen increases with Ti-coverage.

The Ti-covered graphene was exposed to molecular hydrogen (5 min at 1×10-7 mbar deuterium). The sample temperature was then increased up to 550 ºC with a constant heating rate of 10 K/s while measuring the mass-sensitive desorption. The desorption spectra are shown in Fig. 1b. Two desorption peaks at 210 ºC and 290 ºC are clearly visible. Their intensity increases with increasing Ti coverage. We verified that without Ti there was no desorption detectable. Our data demonstrate the stability of hydrogen binding at room temperature and show that the hydrogen desorbes at moderate temperatures – both ideally matching technical requirements for hydrogen storage.

Fig3abFig 2: (a) 100 x 100 nm2 STM image of the distribution of 0.55 ML titanium on a pristine graphene surface. (b) Similar STM image for Ti deposition after sputtering the sample at E = 300 eV for 150 s. The density of the islands is strongly increased, and their individual size decreases.

In order to increase the hydrogen uptake further, we have increased the active surface of the titanium islands on graphene by nitrogen sputtering. As discussed above, when depositing titanium on pristine graphene, titanium atoms cluster and form islands with an average diameter of about 10 nm and an average height of a few atomic layers. As shown in Fig. 2, if defects are introduced in the graphene by ion bombardment, the mobility of the deposited titanium atoms is reduced and the average diameter of the islands decreases to 5 nm with monoatomic height. This results in an optimized coverage for hydrogen storage applications, since the actual titanium surface available per unit graphene area is significantly increased.

Publications:

  1. T. Mashoff, M. Takamura, S. Tanabe, H. Hibino, F. Beltram, and S. Heun: Hydrogen storage with titanium-functionalized graphene, arXiv:1312.1635 [physics.chem-ph].
  2. T. Mashoff, M. Takamura, S. Tanabe, H. Hibino, F. Beltram, and S. Heun: Hydrogen storage with titanium-functionalized graphene, Appl. Phys. Lett. 103, 013903 (2013).
  3. T. Mashoff, D. Convertino, V. Miseikis, C. Coletti, V. Piazza, V. Tozzini, F. Beltram, S. Heun: Increasing the active surface of titanium islands on graphene by nitrogen sputtering, arXiv:1410.2741 [physics.chem-ph].
  4. T. Mashoff, D. Convertino, V. Miseikis, C. Coletti, V. Piazza, V. Tozzini, F. Beltram, S. Heun: Increasing the active surface of titanium islands on graphene by nitrogen sputtering, Appl. Phys. Lett. 106, 083901 (2015).
  5. K. Takahashi, S. Isobe, K. Omori, T. Mashoff, D. Convertino, V. Miseikis, C. Coletti, V. Tozzini, and S. Heun: Revealing the multibonding state between hydrogen and graphene-supported Ti clusters, arXiv:1608.01146 [physics.chem-ph].
  6. K. Takahashi, S. Isobe, K. Omori, T. Mashoff, D. Convertino, V. Miseikis, C. Coletti, V. Tozzini, and S. Heun: Revealing the multibonding state between hydrogen and graphene-supported Ti clusters, J. Phys. Chem. C 120 (2016) 12974 – 12979.
  7. J.-W. Chen, H.-C. Huang, D. Convertino, C. Coletti, L.-Y. Chang, H.-W. Shiu, C.-M. Cheng, M.-F. Lin, S. Heun, F. S.-S. Chien, Y.-C. Chen, C.-H. Chen, and C.-L. Wu: Efficient n-type doping in epitaxial graphene through strong lateral orbital hybridization of Ti adsorbate, arXiv:1603.05862 [cond-mat.mes-hall].
  8. J.-W. Chen, H.-C. Huang, D. Convertino, C. Coletti, L.-Y. Chang, H.-W. Shiu, C.-M. Cheng, M.-F. Lin, S. Heun, F. S.-S. Chien, Y.-C. Chen, C.-H. Chen, and C.-L. Wu: Efficient n-type doping in epitaxial graphene through strong lateral orbital hybridization of Ti adsorbate, Carbon 109 (2016) 300 – 305.
  9. Y. Murata, S. Veronesi, D. Whang, and S. Heun: Morphology of Ti on monolayer nanocrystalline graphene and its unexpectedly low hydrogen adsorption, arXiv:2002.06074 [cond-mat.mtrl-sci].
  10. Y. Murata, S. Veronesi, D. Whang, and S. Heun: Morphology of Ti on monolayer nanocrystalline graphene and its unexpectedly low hydrogen adsorption, J. Phys. Chem. C 123 (2019) 1572.
  11. Hydrogen storage in functionalized graphene, NEST Scientific Report 2014 – 2020.
  12. J.-W. Chen, S.-H. Hsieh, S.-S. Wong, Y.-C. Chiu, H.-W. Shiu, C.-H. Wang, Y.-W. Yang, Y.-J. Hsu, D. Convertino, C. Coletti, S. Heun, C.-H. Chen, and C.-L. Wu: Hydrogen spillover and storage on graphene with single-site Ti catalyst, arXiv:2206.06638 [cond-mat.mtrl-sci].
  13. J.-W. Chen, S.-H. Hsieh, S.-S. Wong, Y.-C. Chiu, H.-W. Shiu, C.-H. Wang, Y.-W. Yang, Y.-J. Hsu, D. Convertino, C. Coletti, S. Heun, C.-H. Chen, and C.-L. Wu: Hydrogen spillover and storage on graphene with single-site Ti catalyst, ACS Energy Lett. 7 (2022) 2297 – 2303.
  14. Letizia Ferbel, Stefano Veronesi, Ylea Vlamidis, Antonio Rossi, Leonardo Sabattini, Camilla Coletti, Stefan Heun: Platinum-Decorated Graphene: Experimental Insight into Growth Mechanisms and Hydrogen Adsorption Properties, arXiv:2309.15637 [cond-mat.mtrl-sci].

Presented at:

  1. T. Mashoff: Functionalized graphene for hydrogen storage, Graphene Day, Pisa, Italy, 9 July 2012 (oral). [Talk]
  2. S. Heun: Hydrogen on Graphene – an STM study, IBM Rueschlikon, Switzerland (Dr. Gerhard Mayer), 23 October 2013 (invited). [Abstract] [Talk]
  3. D. Convertino, V. Miseikis, T. Mashoff, P. Pingue, S. Heun, V. Piazza, and C. Coletti: Growth and characterization of graphene on SiC(0001) and SiC(000-1), Graphene Study 2014, Obergurgl, Austria, 2 – 7 February 2014 (poster). [Poster]
  4. Vaidotas Miseikis, Domenica Convertino, Torge Mashoff, Stefan Heun, Vincenzo Piazza, Camilla Coletti: Growth of homogenous large area graphene on SiC crystals and Cu foil, Graphene 2014, Toulouse, France, 6 – 9 May 2014 (poster). [Poster]
  5. Valentina Tozzini, Dario Camiola, Riccardo Farchioni, Antonio Rossi, Tommaso Cavallucci, Nicola Pugno, Antonino Favata, Stefan Heun, and Vittorio Pellegrini: Multi-Scale Simulations of Graphene for Energy Applications, Graphene 2014, Toulouse, France, 6 – 9 May 2014 (oral). [Abstract] [Talk]
  6. T. Mashoff, M. Takamura, S. Tanabe, H. Hibino, D. Convertino, V. Miseikis, C. Coletti, V. Piazza, F. Beltram, and S. Heun: Hydrogen storage with graphene functionalized by Titanium, International Discussion on Hydrogen Energy and Applications (IDHEA), Nantes, France, 12 – 14 May 2014 (oral). [Abstract] [Talk]
  7. S. Heun: Hydrogen Storage in Graphene, Lectures at the post-graduate course on Graphene at the University of Modena and Reggio Emilia, Italy, 18 – 19 June 2014. [Slides]
  8. T. Mashoff, M. Takamura, S. Tanabe, H. Hibino, D. Convertino, V. Miseikis, C. Coletti, V. Piazza, F. Beltram, and S. Heun: Functionalized graphene as a system for hydrogen storage, Graphene Week, Gothenburg, Sweden, 23 – 27 June 2014 (oral). [Abstract] [Talk]
  9. Valentina Tozzini, Dario Camiola, Riccardo Farchioni, Antonio Rossi, Tommaso Cavallucci, Nicola Pugno, Antonino Favata, Stefan Heun, Vittorio Pellegrini: Designing graphene for energy applications, Graphene Week, Gothenburg, Sweden, 23 – 27 June 2014 (oral). [Abstract] [Talk]
  10. T. Mashoff, S. Goler, V. Tozzini, D. Convertino, V. Miseikis, C. Coletti, V. Piazza, M. Takamura, S. Tanabe, H. Hibino, V. Pellegrini, F. Beltram, and S. Heun: Tailoring graphene for hydrogen storage, SINFO II, Trieste, Italy, 25 – 27 June 2014 (poster). [Abstract] [Poster]
  11. S. Heun: Designing graphene for hydrogen storage, Universität Regensburg, Germany (Prof. M. Grifoni & Prof. F.-J. Giessibl), 04 July 2014 (invited). [Abstract] [Talk]
  12. T. Mashoff, S. Goler, V. Tozzini, D. Convertino, V. Miseikis, C. Coletti, V. Piazza, M. Takamura, S. Tanabe, H. Hibino, V. Pellegrini, F. Beltram, and S. Heun: Graphene for hydrogen storage: an STM study, ICN+T, Vail, Colorado, USA, 20 – 25 July 2014 (invited). [Abstract] [Talk]
  13. S. Heun: Prospects for hydrogen storage in graphene, NSS8, Chicago, USA, 28 – 31 July 2014 (invited). [Abstract] [Talk]
  14. Jhih-Wei Chen, Hung-Wei Shiu, Lo-Yueh Chang, Camilla Coletti, Stefan Heun, Yi-Chun Chen, Chia-Hao Chen, and Chung-Lin Wu: Modification of Fermi Velocity in Epitaxial Graphene, 4th International Symposium on Graphene Devices, Bellevue, Washington, USA, September 21-25, 2014 (oral). [Abstract] [Talk]
  15. S. Heun: Hydrogen Storage in Graphene, Paul Drude Institut, Berlin, Germany (Dr. S. Foelsch), 26 September 2014 (invited). [Abstract] [Talk]
  16. S. Heun: Prospects for Hydrogen Storage in Graphene, Tohoku University, Sendai, Japan (Prof. M. Suemitsu), 30 October 2014 (invited). [Abstract] [Talk]
  17. V. Miseikis, D. Convertino, N. Mishra, M. Gemmi, T. Mashoff, S. Heun, N. Haghighian, F. Bisio, M. Canepa, V. Piazza and C. Coletti: Rapid CVD growth of millimetre-sized single-crystal graphene using a cold-wall reactor, Graphene 2015, Bilbao, Spain, March 10 – 13, 2015 (oral). [Abstract] [Talk]
  18. S. Heun: Hydrogen Storage in Graphene, ISSP, Tokyo University, Kashiwa, Japan (Prof. Y. Hasegawa), 5 August 2015 (invited). [Abstract] [Talk]
  19. S. Heun: Prospects for Hydrogen Storage in Graphene, Hokkaido University, Sapporo, Japan (Dr. K. Takahashi), 3 August 2015 (invited). [Talk]
  20. S. Heun: Hydrogen Storage in Graphene, Institut Neel, CNRS Grenoble, France (Prof. H. Courtois), 16 September 2015 (invited). [Talk]
  21. S. Heun: Prospects for hydrogen storage in graphene, McGill University, Montreal, Canada (Prof. G. Gervais), 28 October 2015 (invited). [Abstract] [Talk]
  22. S. Heun: Prospects for hydrogen storage in graphene, CNR – Istituto di Struttura della Materia, Rome, Italy (Prof. L. Avaldi), 26 November 2015 (invited). [Abstract] [Talk]
  23. S. Heun: 2D Materials, CNR – CONACYT Workshop, Rome, Italy, 14 – 15 April 2016 (invited). [Abstract] [Talk]
  24. Valentina Tozzini, Tommaso Cavallucci, Khatuna Kakhiani, Vito Dario Camiola, Riccardo Farchioni, Yuya Murata, Stefan Heun, Vittorio Pellegrini: Morphing graphene at the nano-scale: from simulations to applications, Graphene 2016, Genova, Italy, 19 – 22 April 2016 (poster). [Abstract] [Poster]
  25. S. Heun: Prospects for hydrogen storage in graphene, Korea-Italy Bilateral Symposium on Beyond Graphene, Hanyang University, Seoul, Korea, 27 May 2016 (invited). [Abstract] [Talk]
  26. Jhih-Wei Chen, Camilla Coletti, Stefan Heun, Chao-Hao Chen, and Chung-Lin Wu: Efficient n-type Doping in Epitaxial Graphene through Strong Lateral Orbital Coupling of Ti Adsorbate, 9th International Conference on Materials for Advanced Technologies ICMAT 2017, Suntec Singapore, 18 – 23 June 2017 (poster). [Abstract] [Poster]
  27. S. Heun: Hydrogen storage in metal-functionalized graphene, 103º Congresso Nazionale della Società Italiana di Fisica, Trento, Italy, 11 – 15 September 2017 (invited). [Abstract] [Talk]
  28. S. Heun: Metal-functionalized graphene for hydrogen storage, SKKU, Seoul, S. Korea (Prof. Dongmok Whang), 21 September 2017 (invited). [Abstract] [Talk]
  29. S. Heun: Hydrogen storage in Ti-functionalized graphene, Italy – Taiwan bilateral symposium on emergent crystalline materials, 9 -10 December 2021 (invited). [Abstract] [Talk] [Video]