Indium oxide supported Pt–In alloy nanocluster catalysts with enhanced catalytic performance toward oxygen reduction reaction

Few currently applied carbon-supported metal cathode catalysts exhibit satisfactory durability under the harsh operation conditions of proton exchange membrane fuel cells. Herein we report for the first time a highly active In 2 O 3 supported Pt–In alloy nanocluster (NC) catalyst (Pt–In/In 2 O 3 ) toward oxygen reduction reaction , with small alloy NCs and a Pt content of 42 wt%, which exhibits obviously enhanced durability compared to currently applied carbon-supported Pt catalysts (Pt/C) and previously reported Pt NCs-based catalysts with a similar Pt content. The mass activity (MA) and specific activity (SA) over Pt–In/In 2 O 3 are 0.32 A·mg −1 Pt and 1.14 mA cm −2 at 0.9 V (vs. reversible hydrogen electrode (RHE)), respectively. Electron transfer from In to Pt in the alloy NCs occurs as confirmed by X-ray absorption measurements, which is an important cause of the high catalytic activity . After an accelerated aging test of 6000 potential cycles between 1.0 and 1.6 V, the MA loss over Pt–In/In 2 O 3 is 3%, but that over Pt/C is 33%. The catalysts subjected to the aging test are characterized by transmission electron microscopy and X-ray diffraction to understand the extremely high durability.