Regulating the Spin‐State of Rare‐Earth Ce Single Atom Catalyst for Boosted Oxygen Reduction in Neutral Medium

Abstract

Abstract The development of neutral zinc–air batteries (ZABs) is long been impeded by the sluggish oxygen reduction reaction (ORR) derived from insufficient O 2 activation and OH* blocking effect. Herein, the synthesis of a series of rare‐earth Ce single‐atom catalysts (CeNCs) is reported with enhanced spin‐state for boosting neutral ORR. Experimental analysis and theoretical calculations indicate that the unique local coordination/geometric structure reshapes the electronic configuration of Ce sites to achieve a transition from 4d 10 4f 1 to 4d 8 4f 3 . The high‐spin Ce active sites accelerate the unpaired f electrons to occupy the anti‐π orbitals of O 2 and generate suitable binding strength with reaction intermediates. In neutral conditions, CeNC‐40 exhibits excellent ORR performance with half‐wave potentials of 0.78 V and negligible decay after 10 000 cycles. Additionally, the self‐breathing ZABs based on CeNC‐40 demonstrates a peak power density of 81 mW cm −2 and impressive long‐cycle stability (>1 600 cycles) at 2 mA cm −2 . This work presents an effective strategy for developing high‐spin catalysts to address the challenges of neutral ZABs.