Activity and Electrochemical Stability of Pt- and Pt2Ni-alpha-WC/C Catalysts for the Oxygen Reduction Reaction in Acid Media

Autor(es)

Bott-Neto, Jose L. ^[1] ; Ticianelli, Edson A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sao Carlos Inst Chem, Dept Phys Chem, Av Trabalhador Sao Carlense 400, Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: CHEMELECTROCHEM; v. 5, n. 10, p. 1364-1372, MAY 2018.
• Citações Web of Science: 3

Resumo

The activity and electrochemical stability of Pt and Pt2Ni alloy nanoparticles supported on carbon (Pt/C, Pt2Ni/C) or on hexagonal tungsten carbide/carbon powders (Pt-alpha-WC/C, Pt2Ni-alpha-WC/C) were investigated for the oxygen reduction reaction (ORR) in 0.1M HClO4. The composites were extensively characterized by different physicochemical techniques, after which the electrochemical active surface area and the electrocatalytic activity for ORR were investigated, before and after being submitted to accelerated stress tests (AST). Results of rotating ring-disk electrode experiments have indicated that Pt2Ni-alpha-WC 20wt.%/C presents the highest initial specific activity (SA) for ORR, about 1.8 times higher than that of a Pt/C catalyst, but also the largest loss of specific activity caused by the AST. This is assigned to a strong catalyst degradation and consequent elimination of positive effects of Ni over Pt in the electrocatalysis of ORR. Although the mass activity of Pt/C electrode was higher after 12000 AST cycles, the specific activity of Pt-alpha-WC20wt.%/C is more stable, indicating that beneficial interactions between Pt and the WC/WOx phases are maintained along the AST. (AU)

• Processo FAPESP: 13/16930-7 - Eletrocatálise V: processos eletrocatalíticos de interconversão entre as energias química e elétrica
• Beneficiário: Edson Antonio Ticianelli
• Modalidade de apoio: Auxílio à Pesquisa - Temático