Using a Dual Plasma Process to Produce Cobalt-Polypyrrole Catalysts for the Oxygen Reduction Reaction in Fuel Cells

Abstract

The chemical structure of cobalt-polypyrrole -produced by a dual plasma process -is analysed by means of X-ray photoelectron spectroscopy (XPS), near edge X-ray absorption spectroscopy (NEXAFS), X-ray diffraction (XRD), energy-dispersive X-Ray spectroscopy (EDX) and extended x-ray absorption spectroscopy (EXAFS).It is shown that only nanoparticles of a size of 3 nm with the low temperature crystal structure of cobalt are present within the compound. Besides that, cobalt-nitrogen and carbon-oxygen structures are observed. Furthermore, more and more cobalt-nitrogen structures are produced when increasing the magnetron power. Linking the information on the chemical structure to the results about the catalytic activity of the films -which are presented in part I of this contribution -it is concluded that the cobaltnitrogen structures are the probable catalytically active sites. The cobalt-nitrogen bond length is calculated as 2.09Å and the carbon-nitrogen bond length as 1.38Å.

Recent Progress in Synthesis, Characterization and Evaluation of Non‐Precious Metal Catalysts for the Oxygen Reduction Reaction

“…In this final paragraph on transition metal‐containing cathode catalyst materials tested in acidic conditions we would like to discuss some studies introducing synthesis approaches for NPMCs not covered in the previous sections. One such method is plasma polymerization of pyrrole alternated with magnetron sputtering of metallic cobalt used to produce cobalt‐polypyrrole films 106–108. This method is rather complex, but the quoted studies are the first proof‐of‐concept that NPMCs can be synthesized using such technique and the produced cobalt‐polypyrrole films seem to possess better catalytic performance than cobalt‐polypyrrole films produced using other techniques.…”

“…XAS is another powerful method for characterizing the local atomic structure of NPMCs. It is far more widely used than Mössbauer spectroscopy and both XANES and EXAFS techniques of XAS provide useful information 51, 56, 57, 80, 107, 108, 111, 179. A difficulty in both XAS and Mössbauer spectroscopy characterization is that they are bulk averaging techniques, and that NPMCs oftentimes may contain several different active site structures as well as inactive structures containing the probed element type, which are very challenging to separate from each other.…”

Recent progress in nanostructured electrocatalysts for PEM fuel cells

“…Pt (111), (100), and (110) index planes or facets are typically found on single-crystal surfaces of bulk Pt. The high index planes have high densities of atomic steps, edges, and kinks that act as active sites for breaking chemical bonds.…”

“…Therefore, it is highly desirable to develop low cost, Pt-free catalysts of high performance. [106][107][108][109][110][111][112][113] 4.1 Metal-free electrocatalysts Due to their wide availability, environmental acceptability, corrosion resistance, and unique surface properties, carbon nanomaterials are ideal candidates for metal-free catalysts. Nitrogen doping of nanostructured carbon is shown to be a promising strategy to obtain fuel cell catalysts with desirable performance.…”

One-Step Electrodeposition of Polypyrrole-Copper Nano Particles for H2O2Detection

“…36,37 Generally, the frequently used methods employed for the synthesis of conducting polymer−metal composites include chemical, electrochemical and electrospinning techniques. [38][39][40][41][42][43] A multistep electropolymerization of conducting polymer composites generally includes electrodeposition of metal particles on the as-prepared polymer surface. 27,28 The electrochemical methods based on one-step processes z E-mail: pooriamn@yahoo.com; pmwoi@um.edu.my; yatimah70@um.edu.my are not frequently applied for synthesizing the conducting polymermetal composites.…”