PtPd Nanonets Derived from Pd@PtPd RDs as High-Performance Catalysts for the Oxygen Reduction Reaction

Pt-based nanoframes with unique morphologies are one of the most promising catalysts for the oxygen reduction reaction (ORR). In this study, stacked Pd@PtPd core–shell rhombic dodecahedrons (Pd@PtPd RDs) were obtained by a solvothermal method, and then PtPd nanonets (PtPd NNs) were formed by etching of Pd@PtPd RDs with Fe(NO3)3 and HNO3. Combining the time-dependent changes of morphology, atomic ratio, and elemental distribution, the formation mechanism of PtPd NNs was explored. According to the electrochemical tests, the mass and specific activities of PtPd NNs were 4.7 and 7.6 times higher than those of Pt/C and 2.5 and 2.2 times as large as those of Pd@PtPd RDs in an alkaline solution, respectively. Meanwhile, PtPd NNs displayed higher stability than Pd@PtPd RDs and Pt/C. The enhanced catalytic performance might result from the unique open structures, the compressive strain, and the electron transfer from Pd to Pt atoms.