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

Abstract

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 O 2 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.

d–sp orbital hybridization: a strategy for activity improvement of transition metal catalysts

“…55,56 For example, Guo et al synthesized Pt-/Co-doped Ti 1− x O 2 nanosheets via an electrostatic adsorption-anchorage strategy. 57 The Pt–Ti 1− x O 2 was found to possess superior activity for the ORR than Co–Ti 1− x O 2 . Based on DFT calculations, the authors reveal that the optimized electronic structure and the improvement of the ORR performance originate from the interatomic interaction between Pt and Ti in Pt–Ti 1− x O 2 , that is, d–d orbital hybridization.…”

A theoretical roadmap for the best oxygen reduction activity in two-dimensional transition metal tellurides

“…For the Pt atom (Figure 2a), the coexistence of unoccupied and occupied d orbitals can facilitate O2 adsorption and activation through a two-way charge transfer, where the unoccupied eg orbital accepts lone-pair electrons from O2, and the occupied t2g orbital donates electrons back to O2 antibonding orbitals. 44,45 This donation and back-donation concept is standard in molecular chemistry (Blyholder model) and has been successfully employed to describe the interaction between small molecules (e.g., N2, C2H4, CO) and transition metal and boron-based catalysts. [46][47][48][49][50][51][52][53] Interestingly, the Te atom possesses an orbital configuration analogous to that of Pt and B atoms in the transition metal stuffed boron nitride nanotube.…”

Breaking the Volcano-Shaped Relationship for Highly Efficient Electrocatalytic Nitrogen Reduction: A Computational Guideline

“…Single-atom catalysts (SACs) have shown simple and unified active centers with well-defined composition and coordination and are considered to be ideal model catalysts to provide in-depth insights into the catalytic mechanism. − In addition, SACs have unique structures that can selectively tune the adsorption configuration and strength of key intermediates compared with the common metal surfaces . Cu-based catalysts are widely used in a number of important electrochemical reactions because of their effective inhibition of hydrogen evolution reaction (HER), high electric conductivity, mild operation conditions, and inexpensive manufacturing costs. − However, due to the fully occupied d orbitals of Cu atoms, the bonding between Cu and N 2 is very weak, making it not applicable for e-NRR .…”