X-Ray Photoelectron Spectroscopy in an Atmosphere of High-Purity Argon as a Method of Studying Functional Materials Using Copper Amalgams as an Example

Abstract

The composition and oxidized state of metals in copper amalgam samples obtained by direct reduction of metals (copper and mercury) in an aqueous solution were studied with X-ray photoelectron spectroscopy (XPS) in the atmosphere of high-purity argon 6.0. The use of XPS in a high-purity argon medium allowed one to exclude the influence of oxygen admixtures in the residual atmosphere of the spectrometer to the state of the amalgam surface and the investigation results. It is shown that the order of metal ions reduction in an aqueous solution of formaldehyde affects the content of oxidized forms of copper. With simultaneous reduction of copper and mercury, the resulting amalgam contains an impurity of 5–7 at. % copper in the form of copper(I) oxide and 8–10 at. % in the form of copper(II) oxide. During the sequential reduction of copper for the first and then mercury, the resulting amalgam contains an impurity of 11–14 at. % copper in the form of copper(II) oxide. During the reduction of copper by washing the resulting powder with dilute acid and subsequent reduction of mercury, the resulting amalgam contains an impurity of 9–11 at. % copper in the form of copper(I) oxide. The state of mercury in the amalgam does not depend on the order of metal reduction.