Recent advances suggest that transition metal oxides, particularly spinel and perovskite materials, can serve as promising electrocatalysts for the oxygen reduction reaction (ORR), a key reaction in fuel cells, under alkaline conditions. These materials offer a potential alternative to scarce and expensive noble metals such as platinum. Developing efficient oxide catalysts could therefore significantly reduce the cost of fuel cell technologies.

Our research focuses on understanding how catalyst structure influences ORR performance. By leveraging crystal shape-controlled synthesis, our work centers on two major aspects: facet-dependent activity and structure-dependent catalytic behavior. Specifically, our research activities include: (1) Design and synthesis of advanced oxide electrocatalysts, such as Mn-based spinel materials with well-controlled particle shapes; (2) Investigation of the relationship between ORR activity/durability and the surface structure of facet-engineered oxide catalysts.

In this project, we developed a simple yet effective strategy for synthesizing uniform MMn₂O₄ spinel nano-octahedra (M = Cu, Co) with exclusively exposed {101} crystal facets. Electrochemical measurements demonstrate that these nano-octahedral catalysts outperform their nanospherical counterparts, as well as many previously reported catalysts, in both activity and stability for ORR in alkaline media. Our studies further suggest that the gradual decline in ORR performance during long-term operation is associated with a reduction in Mn⁺³ surface species on the octahedral facets. These findings highlight the critical role of surface structure and oxidation state in determining catalytic activity and durability, providing valuable insights for the rational design of next-generation oxide electrocatalysts for fuel cell applications.

Further reading materials:

ACS Catal., 12(21) 13663 - 13670 (2022).

ACS Energy Lett., 8(8) 3631 - 3638 (2023).

Electron, 2(3) e62 (2024).