Search

Single-atom iron-nitrogen-carbon materials have demonstrated remarkable potential in catalyzing the oxygen reduction reaction (ORR). In this study, a novel approach is proposed for regulating the microenvironment of single iron sites through the coupling of neighboring Zn with an open-mesoporous carbon plane. This structural arrangement effectively modulates the density of states and d-band center of Fe atoms, resulting in moderate adsorption and desorption of oxygen intermediates and thereby reducing the energy barrier of the ORR. Moreover, the open-mesoporous structure ensures the accessibility of the active sites and facilitates the mass transfer of reactants, intermediates, and products during the ORR. Consequently, the synthesized M-Fe-ZnNC catalyst exhibits enhanced ORR performance and excellent stability. This study serves to inspire the exploration of high-performance non-precious metal catalysts for the ORR, leveraging simultaneous electronic regulation and structure design. [Display omitted] • Dual-atomic Fe-Zn-Nx sites dispersed on an open-mesoporous carbon matrix was synthesized. • Zn atoms and the porous structure modulate the d-band center, dramatically lowering the energy barrier. • M-FeZnNC exhibits exceptional catalytic performance and remarkable stability. [ABSTRACT FROM AUTHOR]

We report on a highly active and stable FeNC non noble metal catalyst for the oxygen reduction reaction in alkaline solution. To prepare the FeNC non noble metal catalyst graphitic carbon nitride (g-C 3 N 4 ) and FeCl 3 are used as nitrogen and iron source, respectively. Iron is proved essential for the high catalyst activity. The best catalyst shows similar onset potential with commercial Pt/C catalyst in alkaline solution. The paper reveals whether the Fe 4 N composite is active in the oxygen reduction reaction. The as prepared catalysts show excellent stability with no change in activity after 10,000 cycles of acceleration test. The stability is explained by the protection effect of layers of graphitic carbon on the surface. The as prepared catalyst catalyzes the ORR via a four electron process with similar kinetics to that of Pt/C. The high activity and stability make this catalyst good candidate in alkaline fuel cell and metal air batteries. [ABSTRACT FROM AUTHOR]

A non metal catalyst for the oxygen reduction reaction is prepared by simply pyrolyzing ion exchange resin D113 in NH 3 . The product is nitrogen doped amorphous carbon. The pyrolysis of D113 exchanged with iron ion results in nitrogen doped graphitic carbon. The amorphous carbon is easier to be doped by NH 3 with higher nitrogen content. The nitrogen doped amorphous carbon is more active than graphitized carbon, together with much improved stability. The higher activity is explained by the higher total nitrogen content and higher pyridinic/graphitic nitrogen percentage. The higher stability is because there is no loss or dissolution of the active sites. The results of this work prove metal element and graphitization of carbon are not necessary factors for nitrogen doped carbon as non noble metal catalyst for the oxygen reduction reaction. [ABSTRACT FROM AUTHOR]

The nitrogen doping effect on a kind of graphitic carbon as non noble metal catalyst for the oxygen reduction reaction is studied. Glycine and NH 3 are chosen as different nitrogen source and different doping sequences are applied. The structural defect of graphitic carbon, total nitrogen content, types of nitrogen species and surface area are different from different treatment. Glycine will not influence the structure of graphitic carbon but NH 3 introduces defects. Glycine introduces high content of nitrogen to graphitic carbon but NH 3 introduces no nitrogen. The best catalyst is prepared by doping graphitic carbon with glycine first then heat treated with NH 3 . Some of the nitrogen species can be removed by further NH 3 treatment, but the relative content of graphitic nitrogen increases, together with increased surface area result in higher activity. [ABSTRACT FROM AUTHOR]

Nitrogen doped carbon material works as non-noble-metal catalyst for the oxygen reduction reaction. In this work the doping effect on two different carbon material by two different nitrogen sources is studied. The carbon material studied is self-prepared carbon ribbon with higher graphitization degree compared with commercial Vulcan XC72 carbon powder. NH 3 and glycine are used as nitrogen sources which produce nitrogen containing functionalities after high temperature pyrolysis. NH 3 doping of carbon ribbon has no positive effect on the ORR activity, while an obvious increase in the activity is found for the glycine doped carbon ribbon. The NH 3 and glycine doped Vulcan carbon show similar activities which are better than undoped Vulcan carbon. The difference is explained by graphitization degree, nitrogen content and type of nitrogen containing functionalities. [ABSTRACT FROM AUTHOR]