Fu, D., Zhu, J., Wang, L. et al. Biradical-mediated synergistic electrocatalysis using metal-free redox molecular catalysts. Nat Commun 16, 11520 (2025). https://doi.org/10.1038/s41467-025-66495-0
Abstract:
Nature’s redox enzymes achieve remarkable selectivity by organizing active sites with precise spatial control, an ability difficult to replicate in synthetic systems. Inspired by this, we report a class of stable, metal-free bicarbenium-based molecular catalysts that undergo electrochemical two-electron reduction to form biradical intermediates. These biradicals are confined within a rigid xanthene bridge (~4.3 Å), creating a spatially defined pocket that engages paramagnetic substrates like O₂ and NO, resembling nature’s synergistic catalysis. This biradical-mediated synergistic catalysis enables highly selective two-electron oxygen reduction (99.3% H2O2 selectivity, 96.8% Faradaic efficiency, 2.21 mol g⁻¹cat h⁻¹ productivity) and three-electron nitric oxide reduction (NH₂OH as major product, 87.2% Faradaic efficiency, 1.68 mol g-¹cat h-¹ productivity). Experimental and computational studies confirm sustained redox cycling supported by favorable spin-pairing and substrate binding geometries, which enhance catalytic selectivity and efficiency. This work demonstrates a blueprint for pathway-specific, radical-mediated catalysis and offers new design principles for metal-free electrocatalytic platforms exploiting open-shell reactivity.
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Funding Info:
This research / project is supported by the Ministry of Education - Academic Research Fund Tier 3 program
Grant Reference no. : MOET32024-0002
This research / project is supported by the A*STAR - Manufacturing, Trade, and Connectivity Individual Research Grant
Grant Reference no. : M22K2c0083
This research / project is supported by the A*STAR - Career Development Fund
Grant Reference no. : C233312013
This research / project is supported by the A*STAR - Manufacturing, Trade, and Connectivity Young Individual Research Grant
Grant Reference no. : M23M7c0118
This research / project is supported by the National Research Foundation - National Research Foundation Fellowship
Grant Reference no. : NRF-NRFF15-2023-0011
This research / project is supported by the A*STAR - Manufacturing, Trade, and Connectivity Programmatic Fund
Grant Reference no. : M24M9b0013
This research / project is supported by the NUS - PYP Start-Up Grant
Grant Reference no. : A-0010024-00-00
This research / project is supported by the NUS - White Space Fund
Grant Reference no. : A-0010024-01-00
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