Spin‐Selective Coupling in Mott–Schottky Er₂O₃‐Co Boosts Electrocatalytic Oxygen Reduction

Abstract

Alkaline oxygen reduction reaction (ORR) is critical to electrochemical energy conversion technology, yet the rational breaking of thermodynamic inhibition for ORR through spin regulation remains a challenge. Herein, a Mott-Schottky catalyst consisting of Er 2 O 3 -Co particles uniformly implanted into carbon nanofibers (Er 2 O 3 -Co/CNF) is designed for enhancing ORR via spin-selective coupling. The optimized Er 2 O 3 -Co/CNF affords a high half-wave potential (0.835 V vs reversible hydrogen electrode, RHE) and onset potential (0.989 V RHE ) for the ORR surpassing individual Co/CNF and Er 2 O 3 /CNF. Theoretical calculations reveal the introduction of Er 2 O 3 optimizes the electronic structure of Co through Er(4f )-O(2p)-Co(3d) gradient orbital coupling, resulting in significantly enhanced ORR performance. Through gradient orbital coupling, the induced spin-up hole in Co 3d states endows the Er-O-Co unit active site with a spin-selective coupling channel for electron transition. This favors the decrease of the energy gap in the potential-limiting step, thus achieving a high theoretical limiting potential of 0.77 V RHE for the Er 2 O 3 -Co. Moreover, the potential practicability of Er 2 O 3 -Co/CNF as an air-cathode is also demonstrated in Zn-air batteries. This work is believed to provide, new perspectives for the design of efficient ORR electrocatalysts by engineering spin-selective coupling induced by rare-earth oxides.

Reinforcing CoO Covalency via Ce(4f)─O(2p)─Co(3d) Gradient Orbital Coupling for High‐Efficiency Oxygen Evolution

“…The gradient orbital coupling of TM-O-RE may lead to promising OER based on the group theory-directed symmetric analysis. [39,40] Both TMOs and REOs with the unique (TMO 6 ) and (REO 6 ) edges share the same O h symmetry (Figure S1, Supporting Information). Owing to the 𝜎 and 𝜋 conjunction donated by O-sp orbitals, the gradient orbital coupling of TM(O h )-O-RE(O h ) can be formed (Figure 1a), making more flexible electronic interactions for electrocatalytic adaptation (e.g., the optimization of e g occupancy and M-O covalency).…”

Constructing atomic single metal Co–C3(OH)1sites with graphdiyne for zinc–air batteries

“…Recently, emerging as a booming field in heterogeneous catalysis, single-atom catalysts (SACs) have sparked great attention due to their high atom utilization and catalytic performance comparable to those of noble metal catalysts. 9–16 Among them, metal–nitrogen–carbon (M–N–C) moieties, employing nitrogen to anchor dispersed metal atoms to form single atomic sites, exhibit good catalytic activity. 17 Specifically, the widely researched carbon-based SACs with M–N 4 sites have been regarded as burgeoning alternatives to noble Pt-based catalysts.…”

High-Valence Mo Doping and Oxygen Vacancy Engineering to Promote Morphological Evolution and Oxygen Evolution Reaction Activity

“…Considerable strategies have been exploited to improve their OER activity. 6−8 Particularly, doping another heteroatom into the lattice of metal oxides can remarkably improve the catalytic performance, 9,10 and highvalence non 3D metal dopants can be more effective, which could modulate the electronic structure of 3d TMO catalysts and optimize the adsorption energy toward OER intermediates, resulting in good catalytic stability and enhanced activity. 11−14 For instance, Mo 6+ is a typical high-valence 4d transition metal ion with a radius of 0.62 Å, 15 which can be doped into the lattice of cobalt oxide as a substitution of Co 3+ (0.63 Å).…”