Highly coordinative molecular cobalt-phthalocyanine electrocatalyst on an oxidized single-walled carbon nanotube for efficient hydrogen peroxide production.

H 2 O 2 production via the two-electron oxygen reduction reaction (2e - ORR) offers a potential alternative to the current anthraquinone method owing to its efficiency and environmental friendliness. However, it is necessary to determine the structures of electrocatalysts with cost-effectiveness and high efficiency for future industrialization demand. Herein, a supramolecular catalyst composed of cobalt-phthalocyanine on a near-monodispersed and oxidized single-walled carbon nanotube (CoPc/o-SWCNT) was synthesized via a solution self-assembly method for catalyzing the 2e - ORR for H 2 O 2 electrosynthesis. Benefiting from the enhanced intermolecular interaction by introducing oxygen functional gr o ups on o-SWCNTs, the oxidation states of single-atom Co sites were tuned via the formation of two extra Co-O bonds. Coupled with structural characterizations, density-functional theory (DFT) calculations reveal that the depressed d-band center of the Co site regulated by two axially-bridged O atoms gives rise to a suitable binding strength of oxygen intermediates (*OOH) to favor the 2e - ORR. Thus, the CoPc-6wt%/o-SWCNT-2 catalyst with optimized synthetic parameters delivers competitive 2e - ORR performance for H 2 O 2 electrosynthesis in a neutral electrolyte (pH = 7), including enhanced H 2 O 2 generation, satisfactory molar selectivity of ∼83-95% and long-period stability (75 h) in H-cell measurement. Moreover, it could also be boosted to show a high current of 45 mA cm -2 , recorded turnover frequency of 25.3 ± 0.5 s -1 and maximum H 2 O 2 production rate of 5.85 mol g -1 h -1 with a continuous H 2 O 2 accumulation of 1.2 wt% in a flow-cell device, which outperformed most of the reported neutral-selective nonprecious metal single-atom catalysts.