Premium
Core–Shell Pd@M (M=Ni, Cu, Co) Nanoparticles/Graphene Ensembles with High Mass Electrocatalytic Activity Toward the Oxygen Reduction Reaction
Author(s) -
Perivoliotis Dimitrios K.,
Sato Yuta,
Suenaga Kazu,
Tagmatarchis Nikos
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201901588
Subject(s) - graphene , oxygen reduction reaction , oxygen reduction , oxygen , electrocatalyst , nanoparticle , shell (structure) , materials science , chemical engineering , catalysis , chemistry , nanotechnology , electrochemistry , electrode , composite material , organic chemistry , engineering
Herein, it is demonstrated that pyrene butyric acid (PBA)‐stabilized metal nanoparticles with core–shell morphology, Pd@M NPs (M=Ni, Cu, Co), non‐covalently supported on graphene (G) sheets, are more active towards oxygen electroreduction in alkaline environments than the benchmark Pd/C catalyst, albeit with a 70 % lower precious metal loading. The PBA‐stabilized Pd@M NPs (M=Ni, Cu, Co)/G ensembles were prepared by employing a simple modified polyol method and galvanic replacement and thoroughly characterized with advanced microscopy imaging and complementary spectroscopic techniques. Electrochemical studies revealed that Pd@Ni NPs /G presents the optimum performance, exhibiting a 30 mV more positive onset potential and 3.2 times greater mass activity over Pd/C. Moreover, chronoamperometric assays showed the minimum activity loss for Pd@Ni NPs /G, not only among its core–shell counterparts but importantly when compared with the benchmark catalyst. The excellent performance of Pd@Ni NPs /G was attributed to the (a) presence of PBA as stabilizer, (b) uniform Pd@Ni NPs dispersion onto the graphene sheets, (c) efficient intra‐ensemble interactions between the two species, (d) existence of the core–shell structure for Pd@Ni NPs , and (e) stability of the Ni core metal under the reaction conditions. Last, the oxygen reduction on Pd@Ni NPs /graphene occurs by the direct four‐electron reduction pathway, showing great potential for use in energy related applications.