A Generalized Coordination Engineering Strategy for Single-Atom Catalysts toward Efficient Hydrogen Peroxide...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Non-noble metal single-atom catalysts (M-SACs) are crucial for efficient two-electron oxygen reduction reactions (2e-ORR).
• The coordination configuration of M-SACs significantly impacts activity and selectivity in hydrogen peroxide (H2O2) electrosynthesis.
• A generalized strategy for rationally designing M-SACs with optimized catalytic capabilities is lacking.

Purpose of the Study:

• To propose a generalized coordination engineering strategy for M-SACs targeting H2O2 electrosynthesis via 2e-ORR.
• To tailor the electronic structure and adsorption strength of intermediates by introducing heteroatoms into the metal-N4 coordination sphere.
• To optimize the electrocatalytic performance of M-SACs for 2e-ORR.

Main Methods:

• Developing a generalized coordination engineering strategy by introducing heteroatoms (O or S) into the first coordination sphere of M-SACs.
• Synthesizing (O, N)-coordinated Co SAC (Co-N3O) and (S, N)-coordinated Ni SAC (Ni-N3S).
• Evaluating the 2e-ORR activity, selectivity, and stability of the synthesized catalysts in alkaline conditions.
• Conducting theoretical kinetics simulations to confirm the 2e-ORR pathway.

Main Results:

• Synthesized Co-N3O and Ni-N3S catalysts exhibit superior 2e-ORR activity (onset potential ≈ 0.80 V vs. RHE) and selectivity (≈ 90%).
• Achieved high H2O2 yield rates of 14.2 mol g⁻¹ h⁻¹ for Co-N3O and 17.5 mol g⁻¹ h⁻¹ for Ni-N3S.
• Demonstrated long-term stability over 12 hours for both catalysts.
• Theoretical simulations confirmed the favorable 2e-ORR pathway.

Conclusions:

• The proposed generalized coordination engineering strategy effectively optimizes M-SACs for 2e-ORR.
• Heteroatom incorporation into the metal-N4 sites enhances catalytic activity and selectivity for H2O2 electrosynthesis.
• The synthesized Co-N3O and Ni-N3S catalysts represent promising alternatives for efficient and selective H2O2 production.