Electrodeposited ultrafine NbOx, ZrOx, and TaO x nanoparticles on carbon black supports for oxygen reduction electrocatalysts in acidic media
KAUST DepartmentImaging and Characterization Core Lab
Physical Sciences and Engineering (PSE) Division
Chemical Science Program
KAUST Catalysis Center (KCC)
Advanced Nanofabrication, Imaging and Characterization Core Lab
Catalysis for Energy Conversion (CatEC)
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AbstractA remarkable electrocatalytic activity was obtained for the oxygen reduction reaction (ORR) in acidic solutions on ultrafine nano-oxide catalysts based on group IV or V elements. By potentiostatic electrodepostion in nonaqueous solutions at 298 K followed by heat treatment in H2 gas, highly dispersed fine nanoparticles of NbOx, ZrOx, and TaOx with sizes of less than 5 nm were prepared and deposited on carbon black (CB) loaded electrodes. These oxide nanoparticles showed high catalytic activities with high onset potentials of 0.96 VRHE (NbOx), 1.02 VRHE (ZrOx), and 0.93 V RHE (TaOx) for the ORR. Owing to the high chemical stability of group IV and V oxides, the catalysts were very stable during the ORR in acidic solutions. Surface characterization and chemical identification were performed using scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). All results clearly indicate the formation of nano-oxide electrocatalysts that show an outstanding ORR performance, whereas the bulk oxides are not active because of the absence of electronic conductivity. The present work demonstrates potential candidates for highly stable, non-noble-metal cathode catalysts for polymer electrolyte fuel cells (PEFCs), where the catalysts are exposed to highly acidic and oxidizing conditions. © 2013 American Chemical Society.
SponsorsThis work was supported in part by the Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST) of the Cabinet Office of Japan, the International Exchange Program of the A3 Foresight Program of the Japan Society for the Promotion of Science (JSPS), and the "Elements Strategy Initiative to Form Core Research Center" (since 2012), of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. One of authors, J.S., appreciates the support of the Global Centers of Excellence (GCOE) Program of JSPS for her work at the University of Tokyo.
PublisherAmerican Chemical Society (ACS)