posted on 2020-03-20, 13:36authored byLiang Song, Zhixiu Liang, Kiyotaka Nagamori, Hiroshi Igarashi, Miomir B. Vukmirovic, Radoslav R. Adzic, Kotaro Sasaki
The
dissolution of Pd and corrosion of carbon supports may reduce
the stability of the Pt monolayer (ML) on Pd-based core catalysts,
which will lead to a decrease in their electrocatalytic performances
toward the oxygen reduction reaction (ORR). Herein, we report preparation
of Pd(111) nanosheets (NS) onto carbon-supported WNi substrates using
CO as a reducing and capping agent. Such PdNS/WNi layers
can significantly enhance the ORR performance of a PdNS/WNi/C catalyst in alkaline and a PtML/PdNS/WNi/C catalyst in acidic media. The dominating Pd(111) facets and
consequently diminished low-coordination sites enhanced their electrocatalytic
activity. Meanwhile, the inhibition of Pd–O formation bonds
even at 1.1 V due to the presence of WNi/C substrates and additional
shape-induced contraction caused by the slight Pd dissolution at the
side edges resulted in the improvement in durability. Furthermore,
the stability of the carbon supports was improved because of the protection
from the well-covered WNi substrates.