Doping Effects of SnO ₂ Nanoparticles Used as Carbon-Free ORR Catalysts for Proton-Exchange-Membrane Fuel Cells

This study investigates the influence of 20 different metal dopants on the performance of SnO 2 (M-doped SnO 2 ) as a catalyst support for proton-exchange-membrane fuel cells (PEMFCs). M-doped SnO 2 supports were synthesized via a solvothermal method, followed by Pt loading using a polyol process. Structural characterization by XRD and EDX confirmed that the dopant elements were successfully incorporated into the SnO 2 lattice. The physical and electrochemical properties of M-doped SnO 2 varied significantly depending on the dopant. It was found that electrocatalytic evaluation identified Mo and Sb as the most effective dopants for increasing the electrochemical surface area (ECSA) and mass activity (MA), respectively. To the best of our knowledge, this is the first study to report the exceptionally high ECSA of the Pt/Mo-SnO 2 system among various metal dopants. Notably, accelerated stability tests under high-potential conditions confirmed that Pt/Mo-SnO 2 exhibits exceptionally high durability, retaining its initial ECSA. This dopant selection in SnO 2 is a crucial strategy for material tailoring and the rational design of next-generation highly durable catalysts.