Unconventional Platinum–Antimony Intermetallic Nanosheets Boost Formic Acid Oxidation Catalysis

ABSTRACT Controllable synthesis of 2D platinum (Pt)‐based nanomaterials with unconventional crystalline phases for formic acid oxidation reaction (FAOR) is highly desired yet challenging in direct formic acid fuel cell (DFAFC). Herein, for the first time, we successfully synthesize Pt‐antimony intermetallic nanosheets (PtSb INSs) with hexagonal close‐packed ( hcp ) phase via a surfactant‐free wet‐chemical method for highly efficient FAOR catalysis, even in the formidable membrane electrode assembly (MEA) medium. The mass and specific activities of PtSb INSs/C achieve 4.7 A mg Pt −1 and 10.2 mA cm −2 , 6.3 and 9.2 times higher than those of commercial Pt/C, along with the superior anti‐poisoning ability of CO and the selectivity of direct FAOR pathway. More importantly, it can realize the superior MEA power density of 386.3 W g Pt −1 and long‐term lifetime of 22 h with only 5.4% decay in a single cell. The coupled experimental results indicate that its hcp ‐phased intermetallic structure with noncontinuous Pt sites and surfactant‐free surface effectively adjusts the coordination environment of Pt, inhibits the formation of CO, and promotes the dehydrogenation pathway, thereby dramatically improving the FAOR and MEA performances. This work is of great significance for driving the synthesis of 2D Pt‐based intermetallic nanomaterials and the commercialization of DFAFC technology.