Heterogeneous molecular Co–N–C catalysts for efficient electrochemical H2O2 synthesis

Abstract

Sustainable hydrogen peroxide can be produced via the oxygen reduction reaction catalyzed by single-atom cobalt–nitrogen–carbon catalysts. However, the precise catalyst atomic structure tailoring remains difficult, limiting the a priori design and activity improvement. We address this limitation by constructing heterogeneous molecular catalysts from cobalt porphyrins adsorbed on a carbon nanotube substrate. Based on the explicit atomistic models, our first-principle calculation suggested that porphyrin β-substituents and the carbon substrate can synergistically modulate Co properties and catalytic activity. An octafluoro-substituted catalyst was predicted as optimal and further validated by experiments, exhibiting >94% H₂O₂ selectivity and a high turnover frequency of 3.51 per second at an overpotential of 200 millivolts in an acid electrolyte. It can reach a maximum H₂O₂ productivity of 10.76 mol_H2O2 g_cat⁻¹ h⁻¹ in a two-electrode electrolyzer, delivering pure H₂O₂ solutions that can be used directly for water treatment and chemical production.