Adsorption of hydrogen on the surface and sub-surface of Cu(111)

Abstract

Articles you may be interested in 1,2-Dibromoethane on Cu(100): Bonding structure and transformation to C2H4 J. Chem. Phys. 135, 064706 (2011) The interaction of atomic hydrogen with the Cu(111) surface was studied by a combined experimental-theoretical approach, using infrared reflection absorption spectroscopy, temperature programmed desorption, and density functional theory (DFT). Adsorption of atomic hydrogen at 160 K is characterized by an anti-absorption mode at 754 cm −1 and a broadband absorption in the IRRA spectra, related to adsorption of hydrogen on three-fold hollow surface sites and sub-surface sites, and the appearance of a sharp vibrational band at 1151 cm −1 at high coverage, which is also associated with hydrogen adsorption on the surface. Annealing the hydrogen covered surface up to 200 K results in the disappearance of this vibrational band. Thermal desorption is characterized by a single feature at ∼295 K, with the leading edge at ∼250 K. The disappearance of the sharp Cu-H vibrational band suggests that with increasing temperature the surface hydrogen migrates to sub-surface sites prior to desorption from the surface. The presence of sub-surface hydrogen after annealing to 200 K is further demonstrated by using CO as a surface probe. Changes in the Cu-H vibration intensity are observed when cooling the adsorbed hydrogen at 180 K to 110 K, implying the migration of hydrogen. DFT calculations show that the most stable position for hydrogen adsorption on Cu(111) is on hollow surface sites, but that hydrogen can be trapped in the second sub-surface layer. © 2013 AIP Publishing LLC. [http://dx

Hydrogen sorption capacity of crystal lattice defects and low Miller index surfaces of copper

“…8. The obtained adsorption energies for both the adsorption of single H-atoms [23,[47][48][49] and for the formation of 1 ML at Cu(100) [49] are in good agreement with literature data. For 1 ML at Cu(100), as previously reported by other authors [49], we also found that the shifted fourfold hollow geometry is more stable than the centered fourfold hollow.…”

Adsorbate-driven morphological changes on Cu(111) nano-pits

“…The spectrum (c) is characteristic of co-adsorbed CO and H, as it shows that the presence of H suppresses the adsorption of CO. 28 The spectrum obtained after similar preparation using flat Cu(111) shows a slightly red shifted peaks at 1132 and 2059 cm À1 for adsorbed H and CO, respectively, as reported previously. 28 Annealing of the system in (c) to 200 K results in the complete desorption of CO and the disappearance of the surface Cu-H vibration peak as shown in spectrum (d) due to the migration of H to sub-surface sites, leading to the formation of a thin copper hydride (CuH) layer as described earlier on Cu(111) surfaces. 28 Spectrum (e) was obtained after re-cooling to 100 K and re-adsorption of CO on top of the CuH surface.…”

Weakly-bound hydrogen on defected Pt(111)

“…Subsurface hydrogen absorption, well known for Pd(110) [33][34][35][36][37], Pd(111) [38][39][40], Pd(100) [41,42], and Pd(311) [43], has been also reported for Ru(0001) [44], Cu(111) [45] and Ni(111) [46]. The diffusion of atomic hydrogen into the subsurface of smooth, but not on defected, Pt(111) surfaces has been suggested experimentally [23,47] and theoretically [48,49].…”