CO induced faceting of Rh(553)

Sammanfattning: We have investigated the CO induced faceting of a Rh(553) surface using Scanning Tunneling Microscope (STM), Low Energy Electron Diffraction (LEED) and Auger Electron Spectroscopy (AES). The sample was exposed to a CO pressure of 1x10^-3 mbar, at different sample temperatures. The experiment was performed in the STM lab at the division of Synchrotron Radiation Research at Lund University. According to a recent surface X-ray diffraction study 1, the Rh(553) was reshaped into (110) and (111) facets, under CO rich reaction conditions for catalytic CO oxidation, in pressures of 0.1-300 mbar. In this project we tried to find if the faceting can also be found by exposure to pure CO at a lower pressure. The main result of the CO exposure, however, is a roughening of the surface. The roughening process is independent on the conditions we performed and the resulting surface consists of a signficant amount of kinked steps and areas of various step size. Local areas of (110) surface is observed, but no systematic change of areas as found in ref. 1. 1 Chu Zhang, Edvin Lundgren, Per-Anders Carlsson, Olivier Balmes, Anders Hellman, Lindsay R Merte, Mikhail Shipilin, Willem Onderwaater, and Johan Gustafson. Faceting of rhodium (553) in realistic reaction mixtures of carbon monoxide and oxygen. The Journal of Physical Chemistry C, 2015.