engleski

Electrochemical quartz crystal microbalance study of electrodeposited ruthenium

Voltammetric and electrochemical quartz crystal microbalance measurements have been used in the characterization of surface electrochemical processes of electrodeposited ruthenium under the conditions of repetitive potential cycling in 0.5 M sulphuric acid solution. The stability of the electrodeposited ruthenium layer and the pseudocapacity of surface electrochemical reactions were measured as a function of potential window and number of cycles. Six different stages of oxide formation and reduction in cyclic voltammogram and cyclic voltmassogram of the first potentiodynamic cycle have been found and discussed. Mass losses or gains were detected depending on whether water from the layer or water from the bulk solution was consumed. Complex voltammetric and mass change behaviour was found when the potential was continously cycled. Several types of non-stoichiometric surface reactions which include various ruthenium oxyhydroxide species and water are presented. The stability of the electrodeposited layer depends on whether ruthenium is reduced to the metallic state or only the Ru(III)/RU(IV) transition is involved in the electrochemical process. In the R/RuO2 transition 26 ng of electrodeposited ruthenium was dissolved per one cycle. The stability was significantly enhanced when the potential range between 0 and 1 V was used. In that case only 18 ng of deposited ruthenium was dissolved after 5400 cycles at 0.5 Hz.

ruthenium ; electrodeposition ; electrochemical quartz crystal microbalance ; electrochemical supercapacitor

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