Pt Islands on 3 D Nut-like PtAg Nanocrystals for Efficient Formic Acid Oxidation Electrocatalysis.

Precise control of structures offers a great opportunity to efficiently tune the catalytic performance of nanomaterials, enhacing both their activity and durability. Herein, we achieve a new class of Pt islands on 3 D nut-like PtAg nanocrystals by exploiting the lower electronegativity of Ag in conjunction with the galvanic replacement of catalytically active Pt to Ag. Such nanostructures coated with Pt nanoparticles, exhibiting exposed facets, and active surface composition enhance formic acid oxidation electrocatalysis with optimized PtAg1 nut-like catalysts and achieved a factor of 4.0 and 2.4 in mass and specific activities (1728.3 mA mg-1 and 3.31 mA cm-2 ) relative to those of the commercial Pt/C (431.2 mA mg-1 and 1.41 mA cm-2 ), respectively. Moreover, such 3 D PtAg1 nut-like catalysts also display great enhancement in durability with less decay for at last 500 cycles, showing a great potential to serve as promising catalysts for fuel cells and other applications. Our work provides a fundamental insight on the effect of the morphology toward liquid fuel electrooxidation, which may pave a new way for the fabrication of highly efficient electrocatalysts for fuel cells.