Growing Tungsten Nanophases on Carbon Spheres Doped with Nitrogen. Behaviour as Electro-Catalysts for Oxygen Reduction Reaction

• Published in: Materials Vol. 14; no. 24; p. 7716
• Main Authors: Briz-Amate, Teresa, Castelo-Quibén, Jesica, Bailón-García, Esther, Abdelwahab, Abdalla, Carrasco-Marín, Francisco, Pérez-Cadenas, Agustín F
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 14-12-2021; MDPI
• Subjects: Adsorption; Carbon; Electrodes; Fuel cells; Microscopy; Nanospheres; Nitrogen; Oxygen reduction reactions; Spheres; Tungsten carbide; United States > US; carbon nanospheres; carbon–tungsten composites; oxygen reduction reaction; tungsten carbide; nitrogen-doped electro-catalysts
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma14247716

This work shows the preparation of carbon nanospheres with a high superficial nitrogen content (7 wt.%), obtained by a simple hydrothermal method, from pyrocatechol and formaldehyde, around which tungsten nanophases have been formed. One of these nanophases is tungsten carbide, whose electro-catalytic behavior in the ORR has been evaluated together with the presence of nitrogen surface groups. Both current and potential kinetic density values improve considerably with the presence of tungsten, despite the significant nitrogen loss detected during the carbonization treatment. However, the synergetic effect that the WC has with other electro-catalytic metals in this reaction cannot be easily evaluated with the nitrogen in these materials, since both contents vary in opposite ways. Nevertheless, all the prepared materials carried out oxygen electro-reduction by a mixed pathway of two and four electrons, showing remarkable electro-catalytic behavior.