Interaction of CO with MnO /Pd(111) Reverse Model Catalytic Interfaces.

Understanding the activation of CO on the surface of the heterogeneous catalysts comprised of metal/metal oxide interfaces is of critical importance since it is not only a prerequisite for converting CO to value-added chemicals but also often, a rate-limiting step. In this context, our current work focuses on the interaction of CO with heterogeneous bi-component model catalysts consisting of small MnO clusters supported on the Pd(111) single crystal surface. These metal oxide-on-metal 'reverse' model catalyst architectures were investigated via temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS) techniques under ultra-high vacuum (UHV) conditions.

Ambient-Pressure X-ray Photoelectron Spectroscopy Characterization of Radiation-Induced Chemistries of Organotin Clusters.

Advances in extreme ultraviolet (EUV) photolithography require the development of next-generation resists that allow high-volume nanomanufacturing with a single nanometer patterning resolution. Organotin-based photoresists have demonstrated nanopatterning with high resolution, high sensitivity, and low-line edge roughness. However, very little is known regarding the detailed reaction mechanisms that lead to radiation-induced solubility transitions.

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.