Improving intrinsic oxygen reduction activity and stability: Atomic layer deposition preparation of platinum-titanium alloy catalysts

Improved activity and stability Pt-based catalysts for the oxygen reduction reaction (ORR) are needed to perpetuate the deployment of polymer electrolyte fuel cells (PEFCs) in the transportation sector. Here, we use atomic layer deposition of TiO₂ and Pt coupled with thermal reductive annealing to prepare Pt₃Ti electrocatalysts. The atomic level synthetic control resulted in Pt₃Ti nanoparticles with high ORR performance, including a mass activity of 1.84 A/mg_Pt and excellent electrochemical stability. The Pt₃Ti nanoparticles show excellent specific activity — 5.3-fold higher than commercial Pt/C and 3-fold higher than polycrystalline Pt, exceeding the performance of any PtTi catalysts reported to date. Combined experimental and computational efforts indicate that Pt enrichment on the Pt₃Ti enhances the activity, and the intrinsic stability of the Pt₃Ti phase provides durability. This knowledge, along with the facile fabrication of alloys by atomic layer deposition, can be leveraged to designed improved performance catalysts.