Mechanism of Cr(III)-based oxide-hydroxide film electrodeposition in an acidic solution
Year: 2024
Type: article
Abstract: The electrodeposition of chromium oxide-hydroxide films from Cr(III) electrolytes has recently become a significant focus in electrochemistry , holding promise for applications in packaging industry and corrosion protection , as an environmentally friendly alternative for Cr(VI). However, the complex behavior of Cr(III) complexes has resulted in a scarcity of precise electrochemical investigations in this field. In this study, we employ in-situ techniques such as Electrochemical Quartz Crystal Microbalance (EQCM) and Electrochemical Scanning Tunneling Microscopy (EC-STM) in conjunction with cyclic voltammetry (CV) to elucidate the mechanisms governing the formation of chromium oxide-hydroxide films through electrodeposition in an acidic environment. CV studies explore the electrochemical reactions involved in the electrodeposition process , showing that hydrogen evolution is the dominant reaction. The resulting interfacial pH changes trigger the hydrolysis of hydrated chromium(III) cations, leading to oligomerization and the precipitation of a chromium hydroxide compound. In-situ monitoring of mass changes during film formation process using EQCM reveals that there is a critical pH range for oxide-hydroxide film formation, outside of which no deposition/precipitation occurs. EC-STM results confirms the formation of a film on the cathode surface , and its sensitivity to the interfacial pH. At a sufficiently high local pH, under our experimental conditions happening at potentials more negative than -0.95 V, the film alters into a state that becomes stable and insoluble.
Source: Electrochimica Acta
Institutions: Leiden University, Tata Steel (Netherlands)
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,870
OpenAlex ID: W4405095136