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Activity and Electrochemical Stability of Pt‐ and Pt 2 Ni‐α‐WC/C Catalysts for the Oxygen Reduction Reaction in Acid Media
Author(s) -
BottNeto José L.,
Ticianelli Edson A.
Publication year - 2018
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201800048
Subject(s) - electrochemistry , electrocatalyst , catalysis , tungsten carbide , rotating ring disk electrode , rotating disk electrode , carbon fibers , oxygen reduction reaction , materials science , carbide , alloy , nickel , electrode , nuclear chemistry , chemistry , cyclic voltammetry , metallurgy , composite material , composite number , organic chemistry
The activity and electrochemical stability of Pt and Pt 2 Ni alloy nanoparticles supported on carbon (Pt/C, Pt 2 Ni/C) or on hexagonal tungsten carbide/carbon powders (Pt‐α‐WC/C, Pt 2 Ni‐α‐WC/C) were investigated for the oxygen reduction reaction (ORR) in 0.1 M HClO 4 . 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 Pt 2 Ni‐α‐WC 20 wt.%/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‐α‐WC20 wt.%/C is more stable, indicating that beneficial interactions between Pt and the WC/WO x phases are maintained along the AST.