Electrocatalytic Evolution of Oxygen Gas at Cobalt Oxide Nanoparticles Modified Electrodes

The electrocatalysis of oxygen evolution reaction (OER) at cobalt oxide nanoparticles (nano-CoOx) modified GC, Au and Pt electrodes has been examined using cyclic voltammetry. The OER is significantly enhanced upon modification of the electrodes with nano-CoOx, as demonstrated by a negative shift in the polarization curves at the nano-CoOx modified electrodes compared to that obtained at the unmodified ones. Scanning electron microscopy (SEM) revealed the electrodeposition of nanometer-size CoOx (average particle size of 200 nm) onto GC electrode. Optimization of the operating experimental conditions (i.e., solution pH and loading level of nano-CoOx) has been achieved to maximize the electrocatalytic activity of nano-CoOx modified electrodes. It has been found that the electrocatalytic activity of the nano-CoOx modified electrodes towards the OER is pH and loading level dependent, while it is substrate independent. The low cost as well as the marked stability of the thus-modified electrodes make them promising candidates in industrial water electrolysis proces

Electrocatalysis of the Oxygen Evolution Reaction at Nickel Oxide Nanoparticles - Modified Electrodes

Electrocatalysis, the approach dealing with enhancing the rates of electrochemical reactions by altering the surface properties of the electrodes on which these reactions proceed has been a topic of rapidly increasing interest. An intensive effort has recently been invested to develop new electrocatalytic materials for several applications such as the anodic oxygen evolution reaction (OER). The OER is principal in water electrolysis, an auxiliary reaction in the production of several substances forming at the cathode, and a side reaction in a number of anodic processes, particularly in the production of chlorine and other oxidizing agents. The recent revolution in nanotechnology has stimulated the development of a large set of novel nano-sized materials for the OER. The use of nano-sized electrodes enhances the mass transport, enlarges the accessible active surface area, lowers the charged currents and reduces the deleterious effects of solution resistance. Herein, we report on the electrocatalytic applications of platinum (Pt), gold (Au) and glassy carbon (GC) electrodes modified with nickel oxide (NiOx) nanoparticles towards the OER. The modification of the electrodes with NiOx nanoparticles has been done electrochemically. The scanning electron microscope (SEM) and the Energy dispersive X-ray spectroscopy (EDXS) are used to evaluate the surface morphology and composition of the modified electrodes. Preliminary results revealed a significant enhancement in the electrocatalytic activity of the GC and Au electrodes towards the OER upon the modification with NiOx nanoparticles. This enhancement appeared in a cathodic shift of 750 mV and 550 mV in the onset potentials of the OER, respectively, on the NiOx-modified GC and Au electrodes

Electrocatalytic activity of nickel oxide nanoparticles-modified electrodes: Optimization of the loading level and operating pH towards the oxygen evolution reaction

The current study addresses the superior electrocatalytic activity of nickel oxide nanoparticles (nano-NiO"x) modified GC, Au and Pt electrodes towards the OER. The electrodeposition of nickel oxide nanoparticles (with an average particle size of 80nm) are believed to enhance the OER reaction. NiOOH phase, as shown from XRD data, participates in the OER mechanism in such a way to facilitate the charge transfer during various steps in the reaction mechanism through a reversible transformation of NiOOH to NiO"2. Optimizing the loading level and the operating pH of the proposed catalyst has been carried out

Enhanced electrolytic generation of oxygen gas at binary nickel oxide–cobalt oxide nanoparticle-modified electrodes

This study addresses the enhancement of the oxygen evolution reaction (OER) on glassy carbon, Au, and Pt electrodes modified with binary catalysts composed of nickel oxide nanoparticles (nano-NiOx) and cobalt oxide nanoparticles (nano-CoOx). Binary NiOx/CoOx-modified electrodes (with NiOx initially deposited) show a high catalytic activity and a marked stability which far exceeds that obtained at the individual oxide-modified electrodes. This enhancement is demonstrated by a marked negative shift (more than ca. 600 mV) in the onset potential of the OER compared to that obtained at the unmodified electrodes. The modified electrodes show a significantly higher long-term stability, over a period of 5 h of continuous electrolysis, without any significant loss of activity towards the OER in alkaline medium. The influence of the solution pH, the loading level, and sequence of deposition of each oxide on the electrocatalytic activity of the modified electrodes is addressed with an aim to maximize the catalytic activity of the modified electrodes towards the OER. SEM imaging is used to disclose the size and morphology of the fabricated nano-NiOx and nano-CoOx binary catalysts at the electrode surface