Enhanced oxygen reduction activity of PtCu nanoparticles by morphology tuning and transition-metal doping

Abstract

Developing active and durable electrocatalysts for oxygen reduction reaction (ORR) is of great significance in proton exchange membrane fuel cells (PEMFCs). Herein, we develop a facile strategy to synthesize PtCu nanoparticles with enhanced ORR performance through morphology tuning and transition-metal doping. Two distinct PtCu nanoparticles, namely nanooctahedrons (NOs) and nanospheres (NSs), are selectively synthesized in presence or absence of W(CO)6via a facile one-pot method. Furthermore, by introducing a small amount of third transition metal, M-doped (M = Sc, Y, La, Gd, Fe) PtCu NOs are obtained. Electrocatalytic results suggest that the ORR performance of PtCu NOs is better than that of PtCu NSs due to the morphology advantages. And the ORR performance of PtCuM NOs is further promoted since the doping effect of transition metals compared to that of PtCu NOs. Particularly, PtCuSc NOs exhibit remarkable mass activity (1.652 mA μg−1Pt) and specific activity (2.093 mA cm−2), which are 9.9 and 7.2 times higher than that of commercial Pt/C catalysts at 0.8 V (vs. RHE). Moreover, after accelerated stability tests, the loss of mass activity for PtCuSc NOs is only 9.2%, which is much lower than that of PtCu NOs (16.5%) and commercial Pt/C (44.3%). This work provides a feasible idea to boost the ORR performances of Pt-based nanoparticles.