The Oxygen Evolution Reaction on Passive Oxide Covered Transition Metal Electrodes in Aqueous Alkaline Solution. Part 1-Nickel
نویسندگان
چکیده
Various aspects of the oxygen evolution reaction (OER) at passive oxide covered polycrystalline Ni electrodes in aqueous alkaline solution were investigated using electrochemical techniques. Steady state polarisation and electrochemical impedance spectroscopy (EIS) were used to measure kinetically significant parameters including the Tafel slope and the reaction order with respect to OH activity. While reproducible values of the Tafel slope were readily observed, the recorded current density at a given applied potential displayed considerable variability over the course of a number of polarisation experiments, rendering difficult the extraction of the experimental reaction order parameter. This problem was resolved by applying relatively mild electrochemical pre-treatment routines to the working electrode. Cyclic voltammetry was used to probe the important issue of the interplay between the nickel oxy-hydroxide surface electrochemistry and the activity of the electrode for the OER. A current transient decay method was employed to estimate the electrode roughness factor. Amongst the mechanistic pathways proposed for the OER in the literature, only two are consistent with the experimental results reported here. The relative merits of these two pathways are discussed and the most likely is identified. The well known Krasil’shchikov mechanism is not suggested.
منابع مشابه
The Oxygen Evolution Reaction on Passive Oxide Covered Transition Metal Electrodes in Alkaline Solution Part II - Cobalt
Details are outlined of an electrochemical investigation of the oxygen evolution reaction (OER) at passive oxide covered polycrystalline Co electrodes in aqueous alkaline solution. Kinetic studies on electrodes subjected to different pre-treatment routines, yielded different values of the Tafel slope and the reaction order with respect to OH activity. Only one mechanistic pathway could account ...
متن کاملThe Oxygen Evolution Reaction on Passive Oxide Covered Transition Metal Electrodes in Alkaline Solution. Part III – Iron
The kinetics of the oxygen evolution reaction (OER) at passive oxide covered polycrystalline Fe electrodes in aqueous alkaline solution were examined using both dc steady state polarisation and ac impedance techniques. It proved difficult to obtain reproducible polarisation data for bright anodes, and so an electrochemical pre-treatment routine was devised. Upon ageing of a given electrode spec...
متن کاملA comparative study of the oxygen evolution reaction on oxidised nickel, cobalt and iron electrodes in base
Despite the recent renewal in interest in the oxygen evolution reaction (OER) at transition metal oxide based electrodes in alkaline solution, the details of the mechanism remain controversial. While most studies focus on a particular oxide in isolation, a consistent experimental examination of the oxides of adjacent elements is likely to be fruitful with respect to mechanistic elucidation. In ...
متن کاملThe Oxygen Evolution Reaction at Manganese oxide Films in Base: Kinetics & Mechanism
Various manganese oxide type Dimensionally Stable Anode (DSA) electrodes were prepared though a simple thermal decomposition technique at different annealing temperatures for their effect on the oxygen evolution reaction (OER). Along with the change in different annealing temperatures, the effects of different metal substrates were also explored. Cyclic Voltammetry was used to analyze the redox...
متن کامل