Doping-Modulated Strain Enhancing the Phosphate Tolerance on PtFe Alloys for High-Temperature Proton Exchange Membrane Fuel Cells

In high-temperature proton exchange membrane fuel cells (HT-PEMFCs), the poisoning of Pt by phosphoric species severely affects the kinetics of the oxygen reduction reaction, which restricts their commercialized application. Herein, for the first time, the phosphate tolerance of PtFe ordered intermetallic alloys is enhanced by a doping-modulated strain strategy via employing a low amount of Cu as a dopant to boost HT-PEMFCs. This Cu doping facilitates the formation of compressive strain in PtFe crystals, consequently altering the electronic structure of electrocatalysts and then benefiting for weakening the adsorption energy between phosphoric acid and Pt surfaces. In addition, the high temperature phosphate adsorption tests also reveal that the dopant of Cu in Pt based electrocatalysts can improve the tolerance of phosphoric acid. The HT-PEMFCs assembled by those cathodic electrocatalysts with the low-Pt loading of 0.5 mg(Pt) cm(-2) achieve a preeminent peak power of 793.5 and 432.6 mW cm(-2) under the condition of H-2-O-2 and H-2-air atmosphere, respectively, or nearly 1.53 and 1.34 times higher as compared with commercial Pt/C electrocatalysts. Moreover, those electrocatalysts also exhibit robust stability under harsh condition in H-2-O-2 atmosphere with negligible activity loss for at least 100 h, exceeding most of other reported ORR electrocatalysts.