Synthesis of Carbon‐Supported Pt–YOx and PtY Nanoparticles with High Catalytic Activity for the Oxygen Reduction Reaction Using a Microwave‐based Polyol Method

Abstract Carbon‐supported PtY alloy nanoparticles were prepared as oxygen reduction reaction (ORR) catalysts by reducing a mixture of cis ‐[Pt(NH 3 ) 2 (NO 2 ) 2 ] or Pt(C 5 H 7 O 2 ) 2 and Y(CH 3 COO) 3 ⋅ 4 H 2 O in ethylene glycol (EG) with microwave (MW) heating. Microstructure and composition analyses of products by using TEM, TEM–energy‐dispersive X‐ray spectroscopy (EDS), XRD, X‐ray photoelectron spectroscopy (XPS), and inductively coupled plasma atomic emission spectroscopy (ICP‐AES) data showed that Pt–YO x /C (Y/Pt=0.11–0.75) catalysts involving amorphous yttrium oxide were formed as major products. When the YO x component in the catalysts was removed by using HNO 3 treatment, Pt 99.1–99.6 Y 0.4–0.9 /C alloy catalysts with low Y contents remained. Higher ORR activity was shown by Pt–YO x /C and PtY/C catalysts than by Pt–Y(OH) 3 /C, Pt–YO x /C, or PtY/C catalysts prepared by using other conventional chemical reduction methods and thermal treatment methods under a H 2 /Ar or Ar atmosphere. The mass activity (MA) and surface specific activity (SA) of the best Pt 99.5 Y 0.5 /C catalyst, MA=245 A g Pt −1 and SA=711 μA cm Pt −2 , were equal to or higher than those of the commercially used Pt 86 Co 14 /C catalyst, MA=245 A g Pt −1 and SA=512 μA cm Pt −2 . The major reasons for the high ORR activity of these Pt–YO x /C and PtY catalysts are discussed. These Pt 99.1–99.6 Y 0.4–0.9 /C alloy catalysts prepared by using acid treatment are new and promising catalysts for use in proton exchange membrane fuel cells (PEMFCs).