Revealing the Role of d Orbitals of Transition-Metal-Doped Titanium Oxide on High-Efficient Oxygen Reduction

Precise catalysis is critical for the high-quality catalysis industry. However, it remains challenging to fundamentally understand precise catalysis at the atomic orbital level. Herein, we propose a new strategy to unravel the role of specific d orbitals in catalysis. The oxygen reduction reaction (ORR) catalyzed by atomically dispersed Pt/Co-doped Ti$_{1−x}$O$_{2}$ nanosheets (Pt$_{1}$/Co$_{1}$–Ti$_{1−x}$O$_{2}$) is used as a model catalysis. The z-axis d orbitals of Pt/Co–Ti realms dominate the O$_{2}$ adsorption, thus triggering ORR. In light of orbital-resolved analysis, Pt$_{1}$/Co$_{1}$–Ti$_{1−x}$O$_{2}$ is experimentally fabricated, and the excellent ORR catalytic performance is further demonstrated. Further analysis reveals that the superior ORR performance of Pt$_{1}$–Ti$_{1−x}$O2 to Co$_{1}$–Ti$_{1−x}$O$_{2}$ is ascribed to stronger activation of Ti by Pt than Co via the d–d hybridization. Overall, this work provides a useful tool to understand the underlying catalytic mechanisms at the atomic orbital level and opens new opportunities for precise catalyst design.