Peptide-Assisted 2-D Assembly toward Free-Floating Ultrathin Platinum Nanoplates as Effective Electrocatalysts.

We demonstrate the 2-D anisotropic formation of ultrathin free-floating Pt nanoplates from the assembly of small nanocrystals using T7 peptide (Ac-TLTTLTN-CONH2). As-formed nanoplates are rich in grain boundaries that can promote their catalytic activities. Furthermore, we demonstrate that a minor number of Pd atoms can selectively deposit on and stabilize the grain boundaries, which leads to enhanced structure stability. The Pd-enhanced Pt polycrystal nanoplates show great oxygen reduction reaction activities with 15.5 times higher specific activity and 13.7 times higher mass activity than current state-of-the-art commercial Pt/C electrocatalysts as well as 2.5 times higher mass activity for hydrogen evolution reaction compared with Pt/C.