Concave Platinum-Copper Octopod Nanoframes Bounded with Multiple High-Index Facets for Efficient Electrooxidation Catalysis.

Multimetallic nanoframes with three-dimensional (3D) catalytic surfaces represent an emerging class of efficient nanocatalysts. However, it still remains a challenge in engineering nanoframes via simple and economical methods. Herein, we report a facile one-pot synthetic strategy to synthesize Pt-Cu nanoframes bounded with multiple high-index facets as highly active electrooxidation catalysts. Two distinct octopod nanoframes, namely, concave PtCu2 octopod nanoframes (PtCu2 CONFs) and ultrathin PtCu octopod nanoframes (PtCu UONFs) were successfully synthesized by simply changing the feeding Pt and Cu precursors. Interestingly, the PtCu2 CONFs are constructed by eight symmetric feet with sharp tips, which are enclosed by high-index facets of n (111)-(111), such as {553}, {331}, and {221}. Benefiting from their 3D accessible surfaces and multiple high-index facets, the self-supported PtCu2 CONFs catalysts exhibit excellent electrocatalytic performance and superior CO-tolerant ability. For methanol oxidation reaction, the PtCu2 CONFs catalysts exhibit more than 7-fold increase in activities, 205 mV lower in the onset potential compared with commercial Pt/C. More importantly, when facing harsh electrochemical reaction conditions, the PtCu2 CONFs are well-preserved in the catalytic activities, architectural features, and stepped surfaces. The PtCu UONFs with 12 ultrathin edges, however, suffer from breakdown. The present work provides guidelines for the rational design and synthesis of nanoframe catalysts with both high activity and stability.