Atomic-Scale Chemical, Physical and Electronic Properties of the Subsurface Hydride of Palladium

Weiss, Paul

关键词: nanoscience;    catalysis;    hydrodesulfurization;   

DOI  :  10.2172/1115420
RP-ID  :  DOE-PSU-46546-F
PID  :  OSTI ID: 1115420

学科分类：纳米科学和纳米技术

美国|英语

来源: SciTech Connect

【 摘 要 】

We employed low-temperature, extreme-high vacuum scanning tunneling microscopy (STM) to investigate the roles of subsurface hydride (H) and deuteride (D) in the surface reconstruction and surface reactivity of Pd{110}. Specifically, we gained the ability to tailor the surface structure of Pd{110} both by preparation method and by deposition of deuterium from the gas phase. We observed thiophene at low coverage on Pd{110} to determine its adsorption orientation and electronic structure through scanning tunneling spectroscopy (STS) ??? namely, conductance spectroscopy and differential conductance imaging. We developed the methods necessary to coadsorb D adatoms with thiophene molecules, and to induce the reaction of individual molecules with predefined subsurface H or D features. In the case of Pd{110}, we found a much more pronounced effect from subsurface D, as it is influenced by the surface directionality. These experiments facilitate an understanding of the role of surface and subsurface H and D in heterogeneous catalytic processes, specifically in the hydrodesulfuization (HDS) of thiophene, an important and ubiquitous component found to be detrimental to petroleum refining.