Nitrogen-doped carbon is a promising metalfree catalyst for oxygen reduction reaction in fuel cel... more Nitrogen-doped carbon is a promising metalfree catalyst for oxygen reduction reaction in fuel cells and metal-air batteries. However, its practical application necessitates a significant cost reduction, which can be achieved in part by using new synthetic methods and improvement of catalytic activity by increasing the density of redox active centers. This can be modulated by using polymer as the carbon and nitrogen sources. Although, superior catalytic activity of such N-doped C has been investigated in details, the electrochemical long-term stability of polymer-derived doped-carbon is still unclear. Herein, in this study we generated N-doped carbon from the most recommended polymer that is comparable to the state-of-the-art materials with porosity as high as 2,086 m 2 g -1 and a nitrogen doping level of 3-4 at.%, of which 56 % is pyrrolic N, 36.1 % pyridinic and *8 % graphitic. The electrochemical characterization shows that N-doped carbon is catalytic toward oxygen reduction in an alkaline electrolyte via a favorable four-electron process, however, not stable under long-term potential scanning. The irreversible electrochemical oxidation of this material is associated with the presence of a significant content or pyrrolic and pyridinic N close to the edge of the carbon network originating from the polypyrrole precursor. These structures are less stable under operating electrochemical potential. The role of polypyrrole as the precursor of N-doped carbons has to be carefully revised since it supplies sufficient number of catalytic sites, but also generates unstable functionalities on the carbon surface.
Nitrogen-doped carbon is a promising metalfree catalyst for oxygen reduction reaction in fuel cel... more Nitrogen-doped carbon is a promising metalfree catalyst for oxygen reduction reaction in fuel cells and metal-air batteries. However, its practical application necessitates a significant cost reduction, which can be achieved in part by using new synthetic methods and improvement of catalytic activity by increasing the density of redox active centers. This can be modulated by using polymer as the carbon and nitrogen sources. Although, superior catalytic activity of such N-doped C has been investigated in details, the electrochemical long-term stability of polymer-derived doped-carbon is still unclear. Herein, in this study we generated N-doped carbon from the most recommended polymer that is comparable to the state-of-the-art materials with porosity as high as 2,086 m 2 g -1 and a nitrogen doping level of 3-4 at.%, of which 56 % is pyrrolic N, 36.1 % pyridinic and *8 % graphitic. The electrochemical characterization shows that N-doped carbon is catalytic toward oxygen reduction in an alkaline electrolyte via a favorable four-electron process, however, not stable under long-term potential scanning. The irreversible electrochemical oxidation of this material is associated with the presence of a significant content or pyrrolic and pyridinic N close to the edge of the carbon network originating from the polypyrrole precursor. These structures are less stable under operating electrochemical potential. The role of polypyrrole as the precursor of N-doped carbons has to be carefully revised since it supplies sufficient number of catalytic sites, but also generates unstable functionalities on the carbon surface.
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Papers by Anna Ignaszak