Controllable synthesis of platinum–tin intermetallic nanoparticles with high electrocatalytic performance for ethanol oxidation

This article proposes a general approach for the preparation of intermetallic nanoparticles of Pt3Sn, PtSn, PtSn2, and PtSn4, triggered by hexamethyldisilazane (HMDS) in conjunction with SnCl2. The ethanol oxidation reaction (EOR) tests demonstrate the improved specific activity of PtxSny intermetallic nanoparticles (PtxSny), due to the lower binding energy between carbon monoxide (CO) and PtxSny, the oxidation state of Sn, and the presence of Pt–Sn bonds on the surface. Strikingly, PtSn with an optimized Pt : Sn ratio of 1 : 1 holds superior EOR performance and stability to other PtxSny intermetallics. In addition, PtxSny intermetallic nanoparticles including PtSn, PtSn2, and even the most Sn-rich PtSn4 hold a higher specific current density than the commercial Pt/C after a long-term test, showing the enhanced stability for the EOR. Furthermore, this method was also successfully extended to the synthesis of other Sn-containing intermetallic nanoparticles, such as Ag3Sn and Cu6Sn5.