Adsorption and Photodesorption of CO from Charged Point Defects on TiO(110).

The adsorption and photochemistry of CO on rutile TiO(110) are studied with scanning tunneling microscopy (STM), temperature-programmed desorption, and angle-resolved photon-stimulated desorption (PSD) at low temperatures. Site occupancies, when weighted by the concentration of each kind of adsorption site on the reduced surface, show that the adsorption probability is the highest for the bridging oxygen vacancies (V). The probability distribution for the different adsorption sites corresponds to very small differences in CO adsorption energies (<0.

Probing equilibrium of molecular and deprotonated water on TiO(110).

Understanding adsorbed water and its dissociation to surface hydroxyls on oxide surfaces is key to unraveling many physical and chemical processes, yet the barrier for its deprotonation has never been measured. In this study, we present direct evidence for water dissociation equilibrium on rutile-TiO(110) by combining supersonic molecular beam, scanning tunneling microscopy (STM), and ab initio molecular dynamics. We measure the deprotonation/protonation barriers of 0.

Strong Temperature Dependence in the Reactivity of H2 on RuO2(110).

Understanding the reactivity of H2 is of critical importance in controlling and optimizing many heterogeneous catalytic processes, particularly in cases where its adsorption on the catalyst surface is rate-limiting. In this work, we examine the temperature-dependent adsorption of H2/D2 on the clean RuO2(110) surface using the King and Wells molecular beam approach, temperature-programmed desorption (TPD), and scanning tunneling microscopy (STM). We show that the adsorption probability of H2/D2 on this surface is highly temperature-dependent, decreasing from ∼0.

Light Makes a Surface Banana-Bond Split: Photodesorption of Molecular Hydrogen from RuO2(110).

The coordination of H2 to a metal center via polarization of its σ bond electron density, known as a Kubas complex, is the means by which H2 chemisorbs at Ru(4+) sites on the rutile RuO2(110) surface. This distortion of electron density off an interatomic axis is often described as a 'banana-bond.' We show that the Ru-H2 banana-bond can be destabilized and split using visible light.

Growth from behind: Intercalation-growth of two-dimensional FeO moiré structure underneath of metal-supported graphene.

Growth of graphene by chemical vapor deposition on metal supports has become a promising approach for the large-scale synthesis of high quality graphene. Decoupling of the graphene from the metal has been achieved by either mechanical transfer or intercalation of elements/molecules in between the metal and graphene. Here we show that metal stabilized two-dimensional (2D)-oxide monolayers can be grown in between graphene and the metal substrate thus forming 2D-heterostructures that enable tuning of the materials properties of graphene.

Seeding atomic layer deposition of alumina on graphene with yttria.

Integrating graphene into nanoelectronic device structure requires interfacing graphene with high-κ dielectric materials. However, the dewetting and thermal instability of dielectric layers on top of graphene makes fabricating a pinhole-free, uniform, and conformal graphene/dielectric interface challenging. Here, we demonstrate that an ultrathin layer of high-κ dielectric material Y2O3 acts as an effective seeding layer for atomic layer deposition of Al2O3 on graphene.

Graphene-nickel interfaces: a review.

Graphene on nickel is a prototypical example of an interface between graphene and a strongly interacting metal, as well as a special case of a lattice matched system. The chemical interaction between graphene and nickel is due to hybridization of the metal d-electrons with the π-orbitals of graphene. This interaction causes a smaller separation between the nickel surface and graphene (0.

Growth of a two-dimensional dielectric monolayer on quasi-freestanding graphene.

Integrating graphene into device architectures requires interfacing graphene with dielectric materials. However, the dewetting and thermal instability of dielectric layers on top of graphene makes fabricating continuous graphene/dielectric interfaces challenging. Here, we show that yttria (Y(2)O(3))--a high-κ dielectric--can form a complete monolayer on platinum-supported graphene.