Engineering Multimetallic Nanocrystals for Highly Efficient Oxygen Reduction Catalysts

Oxygen reduction reaction (ORR) has been extensively investigated as an invariable cathode reaction and the main rate-determining step in proton exchange membrane fuel cells (PEMFCs). To date, various PtM (M = Fe, Co, Ni, Cu)-based nanocrystals with size, shape, composition and structure control have shown the great potential to catalyze this sluggish cathodic reaction. Recent design principles for engineering PtM (M = Fe, Co, Ni, Cu)-based multimetallic nanostructures to make them highly active and stable for ORR are reviewed. After a simple description of the ORR mechanism and a general introduction to recent important progress in the controlled synthesis of monodisperse PtM nanoparticles (NPs) for improving the ORR activity, current efforts and achievements in synthetically tuning the catalytically performance of PtM-based multimetallic nanocrystals for getting highly efficient catalysts to enhance both the activity and stability of ORR are highlighted. These typical highly active and stable catalysts include new structure-controlled PtM (M = Fe, Co) NPs, PtM (M = Fe, Cu)-based core/shell NPs, novel PtFe and PtNi-based nanowires (NWs), three-dimensional (3D) Pt3Ni nanoframes, graphene-supported PtFe NPs, and surface-doped PtNi octahedra. These recently developed Pt-based multimetallic nanocrystals with particular characteristics will offer new opportunities to achieve the real-world fuel cell-based electronic vehicle application.