Sub-1 nm PtSn ultrathin sheet as an extraordinary electrocatalyst for methanol and ethanol oxidation reactions.

Sub-1 nm PtSn nanosheets of 0.6-0.9 nm in thickness were synthesized via a solution colloidal method and were applied as electrooxidation catalysts for methanol oxidation reaction (MOR) and ethanol oxidation (EOR) in alkaline and acid environments. Owing to the specific structural and compositional characteristics, the as-prepared PtSn nanosheets exhibits superior activity and durability relative to commercial Pt black and Pt/carbon catalysts. PtSn nanosheets not only exhibit an outstanding mass activity in MOR (871.6 mA mg Pt-1 ), which is 2.3 times (371 mA mg Pt-1 ) and 10.1 times (86.1 mA mg Pt-1 ) higher than that of commercial Pt/carbon and Pt black respectively, but also display an mass activity in EOR (673.6 mA mg Pt-1 ) with 5.3 times higher commercial Pt black (127.7 mA mg Pt-1 ) and 2.3 times higher than commercial Pt/C catalyst (295 mA mgPt-1 ). The reported value is the highest activity in both MOR and EOR examinations compared to the reported PtSn-based electrocatalysts,. The improved performance may be due to the highly-reactive exposed (1 1 1) facet sites resulted from its sub-1 nm 2D sheet like morphology.