Facile Synthesis of Composition‐Controlled Graphene‐Supported PtPd Alloy Nanocatalysts and Their Applications in Methanol Electro‐Oxidation and Lithium‐Oxygen Batteries

• Published in: Chemistry : a European journal 2017-12, Vol.23 (67), p.17136-17143
• Main Authors: Ye, Seong Ji, Bui, Hieu Trung, Kim, Young Yun, Liao, Kin, Cho, Kyeong Min, Jung, Hee‐Tae, Kang, Yongku, Kim, Do Youb, Park, O Ok
• Format: Article
• Language: English
• Subjects: Alcohols; alloys; Batteries; Catalysis; Catalytic activity; Chemistry; composition control; Crystals; electrochemistry; Graphene; Lithium; Lithium batteries; Metal air batteries; Metals; Methanol; methanol oxidation; Nanocatalysis; Nanocrystals; Oxidation; Oxygen; Palladium; Platinum; Polyvinyl chloride; Stress concentration; Synergism; Synthesis
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201703946

A new and simple approach is reported for the synthesis of uniformly dispersed PtPd alloy nanocatalysts supported on graphene nanoplatelets (GNPs) (PtPd‐GNPs) through the introduction of bifunctional materials, which can modify the GNP surface and simultaneously reduce metal ions. With the use of poly(4‐styrenesulfonic acid), poly(vinyl pyrrolidone), poly(diallyldimethylammonium chloride), and poly(vinyl alcohol) as bifunctional materials, PtPd‐GNPs can be produced through a procedure that is far simpler than previously reported methods. The as‐prepared nanocrystals on GNPs clearly exhibit uniform PtPd alloy structures of around 2 nm in size, which are strongly anchored and well distributed on the GNP sheets. The Pt/Pd atomic ratio and loading density of the nanocrystals on the GNPs are controlled easily by changing the metal precursor feed ratio and the mass ratio of GNP to the metal precursor, respectively. As a result of the synergism between Pt and Pd, the as‐prepared PtPd‐GNPs exhibit markedly enhanced electrocatalytic performance during methanol electro‐oxidation compared with monometallic Pt‐GNP or commercially available Pt/C. Furthermore, the PtPd‐GNP nanocatalysts also show greatly enhanced catalytic activity toward the oxygen reduction/evolution reaction in a lithium‐oxygen (Li‐O2) process, resulting in greatly improved cycling stability of a Li‐O2 battery. Alloy‐enhanced electrocatalysis: A facile strategy is presented for the preparation of composition‐controlled PtPd alloy nanocatalysts on graphene through the introduction of bifunctional materials, which can be used to modify the graphene surface and simultaneously reduce metal ions (see figure). The PtPd‐GNP nanocatalysts show enhanced catalytic activity toward the oxygen reduction/evolution reaction, leading to improved cycling stability in Li‐O2 batteries.