title: Molybdenum-Doped PdPt@Pt Core-Shell Octahedra Supported by Ionic Block Copolymer-Functionalized Graphene as a Highly Active and Durable Oxygen Reduction Electrocatalyst.
abstract: Development of highly active and durable electrocatalysts that can effectively electrocatalyze oxygen reduction reactions (ORR) still remains one important challenge for high-performance electrochemical conversion and storage applications such as fuel cells and metal-air batteries. Herein, we propose the combination of molybdenum-doped PdPt@Pt core-shell octahedra and the pyrene-functionalized poly(dimethylaminoethyl methacrylate)-b-poly[(ethylene glycol) methyl ether methacrylate] ionic block copolymer-functionalized reduced graphene oxide (Mo-PdPt@Pt/IG) to effectively augment the interfacial cohesion of both components using a tunable ex situ mixing strategy. The rationally designed Mo-PdPt@Pt core-shell octahedra have unique compositional benefits, including segregation of Mo atoms on the vertexes and edges of the octahedron and 2-3 shell layers of Pt atoms on a PdPt alloy core, which can provide highly active sites to the catalyst for ORR along with enhanced electrochemical stability. In addition, the ionic block copolymer functionalized graphene can facilitate intermolecular charge transfer and good stability of metal NPs, which arises from the ionic block copolymer interfacial layer. When the beneficial features of the Mo-PdPt@Pt and IG are combined, the Mo-PdPt@Pt/IG exhibits substantially enhanced activity and durability for ORR relative to those of commercial Pt/C. Notably, the Mo-PdPt@Pt/IG shows mass activity 31-fold higher than that of Pt/C and substantially maintains high activities after 10 000 cycles of intensive durability testing. The current study highlights the crucial strategies in designing the highly active and durable Pt-based octahedra and effective combination with functional graphene supports toward the synergetic effects on ORR.
authors.affiliation: Department of Materials Science and Engineering, Korea University , Seoul 02841, Korea.|Materials Architecturing Research Center, Korea Institute of Science and Technology , Seoul 02792, Korea.
authors.forename: Kie Yong
authors.initials: KY
authors.lastname: Cho
authors.affiliation: Department of Materials Science and Engineering, Korea University , Seoul 02841, Korea.
authors.forename: Yong Sik
authors.initials: YS
authors.lastname: Yeom
authors.affiliation: Department of Materials Science and Engineering, Korea University , Seoul 02841, Korea.
authors.forename: Heun Young
authors.initials: HY
authors.lastname: Seo
authors.affiliation: Chemistry Division, Bhabha Atomic Research Centre , Mumbai 400085, India.
authors.forename: Pradip
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Materials Architecturing Research Center, Korea Institute of Science and Technology , Seoul 02792, Korea.
authors.forename: Albert S
authors.identifier: http://orcid.org/0000-0002-1396-1244
authors.initials: AS
authors.lastname: Lee
authors.affiliation: Materials Architecturing Research Center, Korea Institute of Science and Technology , Seoul 02792, Korea.|Nanomaterials Science and Engineering, University of Science and Technology , Daejeon 34113, Korea.
authors.forename: Kyung-Youl
authors.initials: KY
authors.lastname: Baek
authors.affiliation: Department of Materials Science and Engineering, Korea University , Seoul 02841, Korea.|Graduate School of Management of Technology, Korea University , Seoul 02841, Korea.
authors.forename: Ho Gyu
authors.identifier: http://orcid.org/0000-0003-3083-4826
authors.initials: HG
authors.lastname: Yoon
keywords: core−shell structures; electrocatalysts; fuel cells; functionalized graphene; molybdenum doping; multimetallic nanocrystals; octahedra