and this stretching will enhance the adsorption of oxygen-containing species or reduce the cleavage of oxygen-containing species on the Pt surface, which inevitably reduces the ORR activity. Such phenomenon contradicts the mechanism reported in the literature that the Pt-Sn double site can promote the ORR activity. Thirdly, the stability origin of SnOx (tin oxides) in stabilizing Pt metal nanocatalysts awaits discovery, where the stability of the catalysts has always been attributed to the role of Pt-M alloying. These studies have significantly improved the properties of Pt-based catalysts on the RDE, their durability remains a challenge in the actual working conditions of fuel cells. Considering the (electro)chemistry reaction always triggers the agglomeration of nanoparticles, uncovering the impact of tin oxides on the particle mobility and coalescence is of fundamental importance. Overall, there is still a need for a deeper understanding of the role of Sn/SnOx on the catalytic activity and stability of Pt and its alloys.