An X-ray Absorption Spectroscopic Study of Carbon monoxide-adsorbed Cu Surface

Abstract

Adsorption/interaction of Carbon monoxide (CO) on a catalytic surface is the key step in electrochemical conversion of CO2 for environmental consideration. Copper (Cu) is known to be the most efficient catalyst for this purpose. Thus, this paper investigates effects of CO adsorption on the electronic/atomic state of polycrystalline Cu surface by using x-ray absorption spectroscopy (XAS). X-ray absorption near-edge structure (XANES) tells that the Cu K-edge shift +0.2 eV on adsorbing CO. Extended x-ray absorption fine structure (EXAFS) analysis informs that CO adsorption disturbs Cu surface, i.e. increase of Cu-Cu bonding distance and decrease of the coordination number of the first nearest neighbor. Both the results of XANES and EXAFS imply decrease of d-electron density of Cu on the adsorption. Demonstrated is that XAS is very useful in studying the surface phenomena of a catalyst but requires further efforts. Copyright (c) 2014 John Wiley & Sons, Ltd.