Synthesis and Characterization of Monolayer Bimetallic Surfaces: A Synchrotron NEXAFS and XPS Study

摘要

Adsorbate near-edge x-ray absorption fine structure (NEXAFS) is a powerful spectroscopic technique that allows the direct measurement of electron orbital occupancies on model catalyst surfaces. Surface-limited redox replacement (SLRR), also called, when repeatedly performed for the fabrication of bulk layers, electrochemical atomic layer deposition (EC-ALD), is a promising technique for the fabrication of bimetallic surfaces for NEXAFS study (1). SLRR involves the electrodeposition of single sacrificial atomic monolayers and their replacement by a second element via redox galvanic replacement. The exchange reaction is limited by the amount of sacrificial material predeposited (Fig. 1). This technique has been explored as a method of large scale layer-by-layer growth of metals on flat and porous surfaces, as well as the fabrication of catalyst nanoparticles, primarily through the use of Cu or Pb sacrificial layers. (1-11)