Compared to the pure Pt/C nanocatalysts, the Au-modified Pt/C nanocatalysts can maintain the activity after 30,000 cycles between 0.6 and 1.1 V vs. RHE. They explicated the Au clusters stabilize the catalyst by raising the oxidation potential of Pt. Au is inert element under the corrosive ORR conditions owing to its relatively higher electrochemical leaching potential (1.50 V vs 1.18 V) and therefore can help to stabilize Pt atoms. Sun et al. found that doping trance amount of Au can improve the ORR stability of octahedral PtCu alloy nanocrystals because Au helps to suppress the dissolution of low-coordinated Pt atoms. An 8% loss in mass activity was recorded for PtCuAu0.0005/C. Nevertheless, the use of precious metal Au to modify Pt nanocatalysts leads to increased material cost. Huang et al. demonstrated doping Mo element to the surface of Pt3Ni octahedral nanocrystals contributes to both the activity and stability. Their DFT calculations indicate Mo atoms are driven to segregate on the surface of Pt3Ni and locate stably on vertex sites. Then the formed surface Mo-oxide species may be conducive to the ORR stability. These studies on ORR catalysts so far have led to a considerable progress, however, the performance of these ORR catalysts have been only evaluated on ring disk electrode (RDE) in half-cell, lacking the verification of catalysts in MEA stack. More importantly, the method used in preparing the above catalysts involves multi-steps and the use of organic solvents. Additionally, limited by the liquid-phase reduction method, these methods are not suitable for large-scale batch preparation. Therefore, the development of highly stable ORR catalysts with simple methods and low prices is still pending. Dissolution of catalyst components in acidic environment in PEMFC is concerns when designing Pt-based catalysts. Among transition metals, tin is more stable in acidic conditions by virtue of its inertness in acid media compared to other metals such as Fe, Co, Ni. According to the potential-pH diagram, at high potentials (potential range up to 2.2 V), metallic Sn tends to form oxides and remain stable under acidic conditions, and relative results have been reported by a number of experimental studies. However, previous researches pay little attention to the atomic geometry and electronic structures of a metal surface, which presents challenges for the identification of the intrinsic active sites and the design principles for high activity. Firstly, the elemental ratio of Sn in the reported catalysts reaches as high as 25%. A large number of Sn atoms covering the surface of Pt nanoparticles can cause severe losses in ORR active sites. For example, Chen et al. reported Pt3Sn intermetallic compounds with a Sn content of 26.2 at%. The mass activity was reported to be less than 100 mA/mgPt, which is inferior to that of conventional Pt/C catalysts. Secondly, the role of Sn in activity enhancement remains far from satisfactory, which is only interpreted by DFT results. In particular, the structural interaction between Sn and Pt-based catalyst is not clear. In fact, Sn atoms with larger atomic radii would cause tensile stress to Pt lattice in Pt-Sn/C alloy nanocatalysts ,