Spectroscopic and AFM studies of the functionalisation of carbon
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Short presentation to the Faraday discussion No. 173 about our studies of functional groups at carbon surfaces. We have selectively derivatised oxygen groups and can unambiguously identify OH and C=O groups. We are also fairly confident about the presence of O-C-O!
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Spectroscopic and AFM studies of the functionalisation of carbon
- 1. Surface science & catalysis group Cardiff Catalysis Institute 1 XPS, AFM & DFT studies of the functionalization of graphite Dr Philip R. Davies Carlo Buonoa, Robert J. Daviesb, Thomas Jonesa, Jiří Kulhavýc, Ryan Lewisa, David J. Morgana, Neil Robinsona and David J. Willocka Cardiff Catalysis Institute School of Chemistry, Cardiff University Cardiff
- 2. Surface science & catalysis group Cardiff Catalysis Institute 2 Motivation • Carbon catalyst supports • Graphene based sensors • Intracellular nanodiamond sensors HOPG Strategy • Multilayer graphene • Ambient preparation conditions • Surface sensitive analysis • DFT analysis of surface chemistry Highly ordered pyrolytic graphite (HOPG)
- 3. Surface science & catalysis group Cardiff Catalysis Institute 3 Mild acid treatment of HOPG (c) HCl/573K (b) HCl What are the oxygen states? How do they affect Carbon-Metal interactions? 542 537 532 527 Binding energy /eV O(1s) (a) Clean 531.5 533.3 HOPG
- 4. Surface science & catalysis group Cardiff Catalysis Institute 4 Molecule specific labeling: Is OH(a) present? OH(a) + CF3C(O)OC(O)CF3 (g) à CF3C(O)O-(a) + CF3CO2H(g) 688.8 F(1s) (d) HCl/573 K & TFAA (c) HCl/TFAA (a) Clean/TFAA 699 694 689 684 679 Binding energy /eV 532.6 534.0 531.6 O(1s) (d) HCl/ 573 K & TFAA (c) HCl/TFAA (a) Clean 542.0 537.0 532.0 527.0 Binding energy /eV (b) HCl OH(a) 532.6 eV Not all OH is functionalised
- 5. Surface science & catalysis group Cardiff Catalysis Institute à CF3C(OH)O-(a) + H2O(g) 5 Is –CO2H present? (c) HCl/573 K & TFE (b) HCl/TFE -CO2H(a) + CF3CH2OH(g) 699 694 689 684 679 Binding energy /eV F(1s) (a) Clean/TFE 688.4 Not significantly!
- 6. Surface science & catalysis group Cardiff Catalysis Institute 6 C=O ? 688.4 F(1s) (d) (c) (a) -CO(a) + CF3CH2NH-NH2 (g) HCl /573 K /TFH HCl /TFH 690 685 680 Binding energy /eV Clean à CF3CH2NH-N=(a) + H2O(g) C=O(a) 531.5 eV (c) HCl/573K (b) HCl 542 537 532 527 Binding energy /eV O(1s) (a) Clean 531.5 533.3 OH(a) 532.6 eV -C-O-C-(a) 533.3 eV
- 7. Surface science & catalysis group Cardiff Catalysis Institute 7 Gold deposition Au(4f) 84.9! 86.5! 84.0! (c) HCl /573 K & Au! (b) HCl /Au! (a) Clean! 93 Bindin8g8 energy /8e3V 78 HOPG C=O C-O-C OH(a) Cl(2p) (c) (b) (a) 198.0 199.7 205 200 195 Binding energy /eV Au0 Au3+
- 8. Surface science & catalysis group Cardiff Catalysis Institute 8 The Stability of Functional Groups: DFT • Calculated stable structure for OH at graphite edges • High OH density • See Poster 38 for OH….Au
- 9. Surface science & catalysis group Cardiff Catalysis Institute 9 Gold 2015 7th International Gold Conference 26th – 29th July 2015 in Cardiff, UK www.cardiff.ac.uk/gold2015 Abstract submission 1st September – 14th October 2014
- 10. Surface science & catalysis group Cardiff Catalysis Institute 10